Effect of Liming on Phosphate Adsorption Characteristics in the Alfisols of Odisha

Effect of Liming on Phosphate Adsorption Characteristics in the Alfisols of Odisha | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Liming on Phosphate Adsorption Characteristics in the Alfisols of Odisha Debaranjan Sahoo, Prasanna Kumar Das, Prateekshya Mohanty, Bikash Kumar Sahoo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7828814/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Effect of liming on phosphate adsorption was studied in the Alfisols of Odisha. The soils were loamy sand to sandy clay loam in texture, strongly to moderately acidic, low to medium in organic carbon and low in available P contents. There was slight increase in phosphate adsorption by the soils after liming. Langmuir equation was slightly better than the Freundlich equation in describing phosphate adsorption by both limed and unlimed soils. Langmuir bonding energy constant, adsorption maxima, equilibrium and maximum phosphate buffering capacities increased, whereas ΔG 0 of phosphate adsorption and supply parameter of phosphate decreased after liming. Freundlich K increased, whereas Freundlich n decreased after liming. Liming Phosphate adsorption Freundlich and Langmuir equations Equilibrium and maximum phosphate buffering capacity Phosphate supply parameter 1. Introduction Phosphate adsorption is an important property of soil that controls its concentration in the soil solution for subsequent availability to the crop. Adsorption reactions occur at lower P concentrations, whereas at higher P concentration precipitation reactions occur [ 1 ]. Application of lime changes the soil properties which influences phosphate adsorption by soil. Different results have been reported on the effect of liming on phosphate adsorption by soil. Haynes [ 2 ], Paliyal and Verma [ 3 ], Majumdar [ 4 ] reported increase in phosphate adsorption after liming, whereas the decrease in phosphate adsorption after liming has been reported by Holford et al. [ 5 ] and Mora et al. [ 6 ]. Decrease in phosphate adsorption after liming is due to increase in pH causing decrease in the charge and electrostatic potential of positively charged sites of the variable charge components in soil [ 7 ]. Increase in phosphate adsorption after liming is due to neutralization of hydroxy Fe and Al polymers which are initially in amorphous forms and form new phosphate adsorbing surface [ 7 – 8 ]. However, the net effect of liming on phosphate adsorption depends on the factor dominating over the other. Smyth and Sanchez [ 9 ], Reeve and Sumner [ 10 ], Arias and Fernadez [ 11 ] reported that liming has no effect on phosphate adsorption by soil, whereas Anjos and Rowell [ 12 ] observed a small increase in phosphate adsorption after liming in acid soils of Brazil. Acid soils in Odisha, belonging to Alfisols, cover more than 70% of the cultivated area. These soils are mostly light textured and are dominated by low- active clays like Fe and Al oxides and kaolinite. Liming constitutes the major part of management practices of these soils. The present investigation was undertaken to study the effect of lime on phosphate adsorption by these soils since no information is yet available in this respect. This study provides information on phosphate availability and its supplying capacity by these soils after liming, which may help to improve the phosphate management practices in these soils. 2. Materials and methods 2.1 Experimental details Surface soil samples (0-15cm) were collected from the virgin uplands of the representative acid soil areas of Odisha belonging to Alfisols. The selected locations were Khalikani, Bolangir district; Chandaka, Khordha district; Sukinda, Jajpur district; Jashipur, Mayurbhanj district; Ghatagaon, Keonjhar district; Khajuripada, Kandhamal district and Semiliguda, Koraput district. From each location one surface soil sample was collected. Some of the important physical and chemical characteristics of the soils were determined by standard procedures. Free oxide of Fe was determined in Na-citrate-bicarbonate- dithionite extracts of soils [ 13 ]. Amorphous Fe oxide was determined in 0.2 M NH 4 -oxalate + 0.2 M oxalic acid (adjusted to pH 3.0) extracts of soil [ 14 ]. Iron in the extracts was determined colorimetrically as orthophenanthroline red ferrous complex at 490 nm wavelength [ 15 ]. Lime requirement of the soils were determined by modified Woodruff buffer method [ 16 ]. The soil samples were added with required quantities of pure CaCO 3 @0.5LR to pH 6.5 and were incubated for four months maintaining the water content at field capacity. The incubated soil samples were, then, air-dried and ground to pass the entire soil through a 2 mm sieve. The limed soil samples were analysed for various soil properties as in the unlimed soils. 2.2 Phosphate adsorption study To 2.5 g of both limed and unlimed soil samples, taken in duplicate, 50 ml of 0.01M KCl containing 0 to 40 µg P/ml were added. This corresponded to 0 to 800 µg P added to one-gram soil. The objective of adding P- concentrations at this lower range was to avoid precipitation reactions which occurs in soil due to very high pK sp values of different insoluble phosphate compounds of Fe, Al and Ca. Two drops of toluene were added to check the microbial activities. The contents were shaken for continuous one hour and equilibrated for 48 hours with intermittent shakings. After the equilibration period, P- concentration in the filtrate was determined by ascorbic acid method [ 17 ]. Amount of P-adsorbed was determined from the difference of the initial and equilibrium P-concentrations. Phosphate adsorption data was fitted to the linear forms of Freundlich equation (log x/m = log K + n log Ce) and Langmuir equation (Ce/(x/m) = 1/K 1 K 2 + Ce/K 2 ). x/m is the amount of P adsorbed (µg/g), Ce is the equilibrium P concentration (µg/ml). K and n are the Freundlich constants (n < 1), K 1 is a constant related positively to the binding energy of phosphate on the adsorbed surface. K 2 is the adsorption maxima. Equilibrium phosphate buffering capacity (EPBC), maximum phosphate buffering capacity (MPBC) and phosphate supply parameter were calculated using the Langmuir K 1 and K 2 values. EPBC (ml/g) = d(x/m) / dCe = d(K 1 K 2 Ce/1 + K 1 Ce)/dCe = K 1 K 2 / (1 + K 1 Ce) 2 MPBC (ml/g) = d (x/m) /dCe Ce → 0 = K 1 K 2 Supply parameter = [ ( \(\:\frac{x}{m\:}Ce\:)\) / (K 1 K 2 ) 0.5 ] 0.5 ΔG 0 of phosphate adsorption (cal / mole) = - RT ln K 1 3. Results and Discussions 3.1 Initial Soil Characteristics Range values of some important physical and chemical properties of the soils are presented in Table 1 . Positive difference between pH w and the salt pH indicated that the soils were net negatively charged. Soil pH w and the salt pH 1M KCl were positively correlated to each other (r = 0.96**). A major part of exchange acidity (63 to 90%) was constituted by exchangeable Al 3+ and the rest by exchangeable H + . Both exchange acidity and exchangeable Al were positively correlated with each other (r = 0.99 ** ) and were negatively correlated with pH w (r = -0.94** and – 0.95**, respectively). Free iron oxide content in the soils varied from 0.88 to 6.8%. Crystalline Fe 2 O 3 varied from 0.78–6.18% and the rest was in the amorphous form. Significant positive correlation existed between free and crystalline Fe 2 O 3 contents in soil (r = 0.995**). Table 1 Some important physical and chemical properties of the soils and their changes after liming Properties Before liming After liming Texture Loamy sand – sandy clay loam - % Clay 5.4–26.2 - pH w (1:2.5) 4.6–5.7 6.2–7.1 pH (1M KCl) 3.9–4.9 - % Organic carbon 0.27–0.60 0.15–0.37 Exchangeable H + cmol(p + ) kg − 1 0.04–0.13 0.02–0.07 Exchangeable Al 3+ cmol(p + ) kg − 1 0.03–0.71 ND Exchange acidity cmol(p + ) kg − 1 0.11–0.79 0.02–0.07 Available P (Brays I) (mg/kg) 5.25–11.6 3.9–9.5 Exchangeable Ca 2+ cmol(p + ) kg − 1 2.9-7.0 4.51–7.41 Free Fe 2 O 3 (%) 0.88–6.80 1.13–7.03 Crystalline Fe 2 O 3 (%) 0.78–6.18 1.00-6.41 Amorphous Fe 2 O 3 (%) 0.10–0.71 0.12–0.78 3.2 Changes in soil properties after liming Lime requirement of the soils to pH 6.5 varied from 1515 to 2938 mg/kg. Clay, crystalline Fe 2 O 3 , amorphous Fe 2 O 3 , pH w , organic carbon and exchangeable Al together determined 99% of variations (R 2 = 0.99) in the LR of the soils but the relationship of the LR with any of the individual soil properties was not significant. Soil pH increased from 6.3 to 7.1 after liming (Table 1 ). There was decrease in organic carbon content in soil after liming which might be due to increase in the microbial activities causing an increase in the decomposition of organic matter. Exchange acidity decreased and exchangeable Al was not detected in any of the soils after liming. Exchangeable Ca 2+ content in the soils increased after liming. Ca 2+ added to the soils through liming varied from 1.52 to 2.94 cmol(p + ) kg − 1 . Increase in exchangeable Ca 2+ after liming varied from 1.54 to 2.90 cmol(p + ) kg − 1 . The lowest increase was in Khajuripada soil which was having the lowest lime requirement of 758 mg pure CaCO 3 /kg (@ 0.5 LR). Exchangeable Ca content in this soil before liming was 5.28 cmol(p + ) kg − 1 . The highest increase was in Semiliguda soil, having the highest lime requirement of 1469 mg pure CaCO 3 /kg (@ 0.5 LR). Exchangeable Ca 2+ content in this soil before liming was 4.51 cmol(p + ) kg − 1 . Available P in soil decreased slightly after liming. All the forms of Fe 2 O 3 in soil increased after liming. A part of the amorphous Fe 2 O 3 might be slowly organized to crystalline form causing an increase in crystalline and free Fe 2 O 3 contents in soil. Increase in all these forms of Fe 2 O 3 after liming has also been reported by Majumdar et al. [ 4 ]. 3.3 Effect of liming on phosphate adsorption: Equilibrium concentrations of phosphorous and the amount of P adsorbed increased, whereas per cent P adsorbed decreased in both limed and unlimed soils with increasing concentrations of P-added (Table 2 ). Increase in P adsorption was due to increasing contacts of phosphate ions with soil. Decrease in per cent adsorption was due to increase in the ionic population of phosphate for adsorption by the same number of adsorption sites. Phosphate adsorption increased slightly after liming. The slight increase in phosphate adsorption might be due to a small increase in amorphous Fe 2 O 3 content in the soils after liming. Similar results have also been reported by Anjos and Rowell [ 12 ]. Table 2 Equilibrium P-concentration and P-adsorbed by the soils before and after liming Conc. of P added (µg ml − 1 ) Equilibrium P conc. (µg ml − 1 ) P adsorbed (µg g − 1 ) % P adsorbed Before liming After liming Before liming After liming Before liming After liming 4 0.06–0.8 0.035–0.59 64-78.8 68.2–79.3 80.0-98.5 85.3–99.1 8 0.21–1.67 0.185–1.25 126.6-155.8 135-156.3 79.1–97.4 84.4–97.7 12 0.56–2.95 0.52–2.75 181.2-228.2 185–229 75.4–95.3 77.1–95.7 16 0.92–5.69 0.90–5.23 206.4-301.7 215.4-302.5 64.4–94.3 67.3–94.4 20 1.98–8.16 1.90–6.62 236.8–361 242-362.1 59.2–90.1 66.9–90.5 24 3.11–11.83 3.00-11.13 243.4-417.8 257.4-420.1 50.7–87.0 53.6–87.5 28 5.26-14.0 4.97–13.22 280-454.8 295.6-460.6 50-81.2 52.8–82.3 32 7.46–16.63 7.05–15.98 307.4-490.8 319-499.1 48.0-76.7 50.1–78.0 36 10.88–20.34 10.42–19.43 313.2-502.3 331.4-511.6 43.5–69.8 46.0-71.1 40 14.06–23.21 13.67–22.45 335.8-518.8 351-526.1 42.0-64.9 43.9–65.8 3.4 Change in the distribution coefficient of phosphorus after liming: Distribution coefficient (Kd) of phosphorus is the amount of P adsorbed (µg/g) /equilibrium P concentration (µg/ml). It is a simple partition model between the phosphate in the soil solution and in the adsorbed phases. It is used as a measure of phosphate availability by different workers [ 18 ]. Kd values decreased in both limed and unlimed soils with increase in the P-concentration added. This was due to the number of times the amount of P adsorbed increased was less than the number of times of the increase in the equilibrium P concentration. Kd values in the limed soils were higher than in the unlimed soils and this difference decreased with increasing concentrations of P added (Table 3 ). However, the higher Kd values in the limed than in the unlimed soils indicated increase in the affinity of phosphate to the adsorbed phase than to the solution phase after liming. Table 3 Kd of phosphorus before and after liming Conc. of P added (µg ml − 1 ) Kd (ml g − 1 ) Before liming After liming 4 80-1313.33 115.59-2265.71 8 75.81–741.90 108.0-844.86 12 61.63-408.57 67.27-440.38 16 36.31-329.73 41.19-345.71 20 29.02-182.32 36.67-191.08 24 20.57-134.34 23.13-140.27 28 20.0-86.46 22.36–92.68 32 18.48–65.79 19.96–70.84 36 15.31–46.15 17.06–49.10 40 14.43–36.90 15.63–38.49 3.5 Comparison of the Freundlich and Langmuir equations to describe the phosphate adsorption The P-adsorption data of both limed and unlimed soils could be fitted to both Freundlich and Langmuir equations as indicated by the highly significant positive ‘r’ values between the dependent and independent variables in the linear forms of these equations. The ‘r’ values were higher in case of Langmuir equation than in the Freundlich equation indicating that the former was better than the latter in describing the phosphate adsorption by both limed and unlimed soils (Table 4 ). Table 4 ‘r’ values between the dependent and independent variables in the liner forms of the adsorption equations Adsorption equation ‘r’ values BL Average AL Average Freundlich equation 0.94** to 0.98** 0.97 0.96** to 0.99** 0.97 Langmuir equation 0.97** to 0.99** 0.98 0.97** to 0.99** 0.98 The adsorption constants Freundlich K, Langmuir K 1 and K 2 increased after liming, whereas Freundlich ‘n’ decreased after liming (Table 5 ). Langmuir K 1 which is the ratio of phosphate adsorption to desorption rate constants increased after liming indicating that phosphate was held more strongly on the clay surface after liming. Langmuir K 2 which is the maximum phosphate adsorption capacity of soil increased slightly after liming. It varied from 370–544 µg/g in the unlimed soils and from 385 to 550 µg/g in the limed soils. The ΔG 0 values of phosphate adsorption decreased after liming which is due to increase in Langmuir K 1 . Table 5 Freundlich and Langmuir adsorption constants and their changes after liming Adsorption constant BL AL Freundlich K(µg/g) 88.9 to 220.8 105.9 to 257.0 Freundlich n 0.280 to 0.51 0.270 to 0.464 Langmuir K 1 (ml/µg) 0.186 to 3.07 0.254 to 3.70 Langmuir K 2 (µg/g) 370.4 to 543.8 384.6 to 549.5 ∆G 0 of P-adsorption (cal mol − 1 ) -664 to 996 -775 to 812 MPBC(ml/g) 87.3 to 1457.7 120.4 to 1474.8 3.6 Change in the equilibrium and maximum phosphate buffering capacities of the soils after liming Equilibrium phosphate buffering capacity of soil indicates the change in the amount of P adsorbed (x/m) per unit change in equilibrium P concentration and is a function of phosphate saturation in soil. In both limed and unlimed soils, EPBC decreased with increasing concentrations of P-added due to increasing P-saturation in soil (Table 6 ). It increased after liming due to increase in both Langmuir K 1 and K 2 and decrease in equilibrium P concentration. Maximum phosphate buffering capacity (MPBC) is the change in the amount of P-adsorbed per unit change in its equilibrium concentration when phosphate saturation in soil is negligible and almost all the adsorption sites are free for phosphate adsorption. It is a fundamental property of soil which integrates both intensive (K 1 ) and extensive (K 2 ) properties of soil and is independent of nutrient saturation in soil [ 19 ]. After liming MPBC of all the soils increased. It varied from 83 to 1457 ml/g in the unlimed soils and 120 to 1475 ml/g in the limed soils (Table 6 ). Increase in MPBC after liming was due to increase in both Langmuir K 1 and K 2 . MPBC possessed a strong positive correlation with Langmuir K 1 (r = 0.97**) in both unlimed and limed soils. With increase in K 1 , binding strength of the adsorbed phosphate on the clay surface increases and its desorption to the soil solution decreases to increase the MPBC. It was negatively correlated with ∆G 0 (r= -0.94**) in both unlimed and limed soils. Table 6 Effect of lime on the EPBC and supply parameter of phosphate in soils Conc. of P added (µg ml − 1 ) EPBC (ml/g) Supply parameter BL AL BL AL 4 66.2—559.0 94.8-614.3 0.43–2.3 0.33–1.8 8 36.8-380.1 50.5-485.3 1.1–4.7 0.93–3.8 12 9.7-234.2 13.2-257.6 2.2–7.6 1.9–6.5 16 2.82–148.1 4.1-155.4 3.3–10.7 2.8–9.5 20 1.4–56.9 2.6–57.6 5.3–14.0 4.6–12.7 24 0.68–28.5 0.96–28.9 7.1–17.0 6.2–15.7 28 0.49–12.1 0.68–12.4 9.3–20.2 8.3–18.6 32 0.35–8.3 0.47–8.5 11.2–23.2 10.3–21.4 36 0.24–6.7 0.32–6.9 12.9–26.1 12.7–24.2 40 0.18–5.3 0.242-5.4 14.4–29.0 13.4–27 3.7 Change in supply parameter of phosphorus with liming Supply parameter integrates the effect of quantity, intensity and buffering capacity of phosphate on P-supply from the adsorbed surface to the plant root [ 20 ]. It increased with increasing concentrations of P- added in both limed and unlimed soils due to increase in both x/m and Ce values (Table 6 ). It decreased in all the soils after liming which was due to increase in both Langmuir K 1 and K 2 . Conclusion Acid soils of Odisha belonging to Alfisols are low in available P. Increase in equilibrium buffering capacity, maximum buffering capacity and decrease in P supply parameter after limimg indicated that availability of the adsorbed phosphate in limed soils will continue for a longer period although its immediate availability decreases as compared to the unlimed soils. This may necessitate to apply a higher dose of P in these soils after liming to increase the crop yield. Declarations Ethics, consent to participate and consent to publish declaration Not applicable Clinical trial number Not applicable Competing interests The authors declare that there is no competing interest exists. Funding The authors received no specific funding for this research. Author Contribution Conceptualization; DS, PKD., Methodology; DS., PKD., Analysis; DS., Writing original draft preparation; PM., PKD., Writing, review and editing; PM; BKS., Supervision; PKD Acknowledgement This experiment was supported by the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Siksha ‘O’ Anusandhan Deemed to be University, Bhubaneswar, Odisha, India. The authors acknowledge all the necessary support provided during the study Data Availability The data are available within the manuscript. References Lin C, Busscher WJ, Douglas LA. Multifactor kinetics of phosphate reactions with minerals in acidic soils modelling and simulation.Soil. Sci Soc Am J. 1983;47:1097–103. Hayens RJ. Effect of lime and phosphate applications on the adsorption of phosphate, sulfate and molybdate by a spodosol. Soil Sci. 1982;135:221–3. Paliyal SS, Verma TS. 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An improved Woodruff buffer for estimation of lime requirements. Soil Sci Soc Am J. 1984;48:587–92. Murphy J, Riley JP. A modified single solution method for the determination of phosphate in natural waters. Anal Chem Acta. 1962;27:31–6. Tomar NK, Gautam KK. Effect of soil properties on hydrolysis of ammonium polyphosphate and tetrapotassium pyrophosphate in some arid and semiarid soils. Arid Soil Res Rehabil. 1996;10(1):43–51. Holford ICR, Mattingly GEG. A model for the behaviour of labile phosphate in soil. Plant Soil. 1976;44:219–29. Khasawneh FE. Solution ion activity and plant growth. Soil Science Society of America Proceeding 35: 426–436 (1971). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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20:24:26","extension":"html","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72817,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7828814/v1/a48ec7ea241b35aa7e6c397e.html"},{"id":101304937,"identity":"0f381cb6-7a71-4da3-8c93-849b970f31cb","added_by":"auto","created_at":"2026-01-28 10:03:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":983553,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7828814/v1/76e6f9e3-5148-474d-8eec-b28fafe4643c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of Liming on Phosphate Adsorption Characteristics in the Alfisols of Odisha","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePhosphate adsorption is an important property of soil that controls its concentration in the soil solution for subsequent availability to the crop. Adsorption reactions occur at lower P concentrations, whereas at higher P concentration precipitation reactions occur [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Application of lime changes the soil properties which influences phosphate adsorption by soil. Different results have been reported on the effect of liming on phosphate adsorption by soil. Haynes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], Paliyal and Verma [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], Majumdar [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] reported increase in phosphate adsorption after liming, whereas the decrease in phosphate adsorption after liming has been reported by Holford et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and Mora et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Decrease in phosphate adsorption after liming is due to increase in pH causing decrease in the charge and electrostatic potential of positively charged sites of the variable charge components in soil [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Increase in phosphate adsorption after liming is due to neutralization of hydroxy Fe and Al polymers which are initially in amorphous forms and form new phosphate adsorbing surface [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, the net effect of liming on phosphate adsorption depends on the factor dominating over the other. Smyth and Sanchez [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], Reeve and Sumner [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], Arias and Fernadez [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] reported that liming has no effect on phosphate adsorption by soil, whereas Anjos and Rowell [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] observed a small increase in phosphate adsorption after liming in acid soils of Brazil. Acid soils in Odisha, belonging to Alfisols, cover more than 70% of the cultivated area. These soils are mostly light textured and are dominated by low- active clays like Fe and Al oxides and kaolinite. Liming constitutes the major part of management practices of these soils. The present investigation was undertaken to study the effect of lime on phosphate adsorption by these soils since no information is yet available in this respect. This study provides information on phosphate availability and its supplying capacity by these soils after liming, which may help to improve the phosphate management practices in these soils.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Experimental details\u003c/h2\u003e\u003cp\u003eSurface soil samples (0-15cm) were collected from the virgin uplands of the representative acid soil areas of Odisha belonging to Alfisols. The selected locations were Khalikani, Bolangir district; Chandaka, Khordha district; Sukinda, Jajpur district; Jashipur, Mayurbhanj district; Ghatagaon, Keonjhar district; Khajuripada, Kandhamal district and Semiliguda, Koraput district. From each location one surface soil sample was collected. Some of the important physical and chemical characteristics of the soils were determined by standard procedures. Free oxide of Fe was determined in Na-citrate-bicarbonate- dithionite extracts of soils [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Amorphous Fe oxide was determined in 0.2 M NH\u003csub\u003e4\u003c/sub\u003e-oxalate\u0026thinsp;+\u0026thinsp;0.2 M oxalic acid (adjusted to pH 3.0) extracts of soil [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Iron in the extracts was determined colorimetrically as orthophenanthroline red ferrous complex at 490 nm wavelength [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Lime requirement of the soils were determined by modified Woodruff buffer method [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The soil samples were added with required quantities of pure CaCO\u003csub\u003e3\u003c/sub\u003e @0.5LR to pH 6.5 and were incubated for four months maintaining the water content at field capacity. The incubated soil samples were, then, air-dried and ground to pass the entire soil through a 2 mm sieve. The limed soil samples were analysed for various soil properties as in the unlimed soils.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Phosphate adsorption study\u003c/h2\u003e\u003cp\u003eTo 2.5 g of both limed and unlimed soil samples, taken in duplicate, 50 ml of 0.01M KCl containing 0 to 40 \u0026micro;g P/ml were added. This corresponded to 0 to 800 \u0026micro;g P added to one-gram soil. The objective of adding P- concentrations at this lower range was to avoid precipitation reactions which occurs in soil due to very high pK\u003csub\u003esp\u003c/sub\u003e values of different insoluble phosphate compounds of Fe, Al and Ca. Two drops of toluene were added to check the microbial activities. The contents were shaken for continuous one hour and equilibrated for 48 hours with intermittent shakings. After the equilibration period, P- concentration in the filtrate was determined by ascorbic acid method [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Amount of P-adsorbed was determined from the difference of the initial and equilibrium P-concentrations. Phosphate adsorption data was fitted to the linear forms of Freundlich equation (log x/m\u0026thinsp;=\u0026thinsp;log K\u0026thinsp;+\u0026thinsp;n log Ce) and Langmuir equation (Ce/(x/m)\u0026thinsp;=\u0026thinsp;1/K\u003csub\u003e1\u003c/sub\u003eK\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;Ce/K\u003csub\u003e2\u003c/sub\u003e). x/m is the amount of P adsorbed (\u0026micro;g/g), Ce is the equilibrium P concentration (\u0026micro;g/ml). K and n are the Freundlich constants (n\u0026thinsp;\u0026lt;\u0026thinsp;1), K\u003csub\u003e1\u003c/sub\u003e is a constant related positively to the binding energy of phosphate on the adsorbed surface. K\u003csub\u003e2\u003c/sub\u003e is the adsorption maxima. Equilibrium phosphate buffering capacity (EPBC), maximum phosphate buffering capacity (MPBC) and phosphate supply parameter were calculated using the Langmuir K\u003csub\u003e1\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003e values.\u003c/p\u003e\u003cp\u003eEPBC (ml/g)\u0026thinsp;=\u0026thinsp;d(x/m) / dCe\u0026thinsp;=\u0026thinsp;d(K\u003csub\u003e1\u003c/sub\u003eK\u003csub\u003e2\u003c/sub\u003eCe/1\u0026thinsp;+\u0026thinsp;K\u003csub\u003e1\u003c/sub\u003eCe)/dCe\u0026thinsp;=\u0026thinsp;K\u003csub\u003e1\u003c/sub\u003eK\u003csub\u003e2\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003e (1\u0026thinsp;+\u0026thinsp;K\u003csub\u003e1\u003c/sub\u003eCe)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eMPBC (ml/g)\u0026thinsp;=\u0026thinsp;d (x/m) /dCe \u003csub\u003eCe \u0026rarr; 0\u003c/sub\u003e = K\u003csub\u003e1\u003c/sub\u003eK\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003cp\u003eSupply parameter = \u003cb\u003e[\u003c/b\u003e(\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{x}{m\\:}Ce\\:)\\)\u003c/span\u003e\u003c/span\u003e\u003cb\u003e/\u003c/b\u003e(K\u003csub\u003e1\u003c/sub\u003eK\u003csub\u003e2\u003c/sub\u003e)\u003csup\u003e0.5\u003c/sup\u003e\u003cb\u003e]\u003c/b\u003e\u003csup\u003e0.5\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eΔG\u003csup\u003e0\u003c/sup\u003e of phosphate adsorption (cal / mole)\u0026thinsp;=\u0026thinsp;-\u0026thinsp;RT ln K\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and Discussions","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Initial Soil Characteristics\u003c/h2\u003e\u003cp\u003eRange values of some important physical and chemical properties of the soils are presented in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003ePositive difference between pH\u003csub\u003ew\u003c/sub\u003e and the salt pH indicated that the soils were net negatively charged. Soil pH\u003csub\u003ew\u003c/sub\u003e and the salt pH\u003csub\u003e1M KCl\u003c/sub\u003e were positively correlated to each other (r\u0026thinsp;=\u0026thinsp;0.96**). A major part of exchange acidity (63 to 90%) was constituted by exchangeable Al\u003csup\u003e3+\u003c/sup\u003e and the rest by exchangeable H\u003csup\u003e+\u003c/sup\u003e. Both exchange acidity and exchangeable Al were positively correlated with each other (r\u0026thinsp;=\u0026thinsp;0.99\u003csup\u003e**\u003c/sup\u003e) and were negatively correlated with pH\u003csub\u003ew\u003c/sub\u003e (r = -0.94** and \u0026ndash; 0.95**, respectively). Free iron oxide content in the soils varied from 0.88 to 6.8%. Crystalline Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e varied from 0.78\u0026ndash;6.18% and the rest was in the amorphous form. Significant positive correlation existed between free and crystalline Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e contents in soil (r\u0026thinsp;=\u0026thinsp;0.995**).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSome important physical and chemical properties of the soils and their changes after liming\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eProperties\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBefore liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAfter liming\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTexture\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLoamy sand \u0026ndash; sandy clay loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e% Clay\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.4\u0026ndash;26.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epH\u003csub\u003ew\u003c/sub\u003e (1:2.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.6\u0026ndash;5.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.2\u0026ndash;7.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epH (1M KCl)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.9\u0026ndash;4.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e% Organic carbon\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.27\u0026ndash;0.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.15\u0026ndash;0.37\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExchangeable H\u003csup\u003e+\u003c/sup\u003e\u003c/p\u003e\u003cp\u003ecmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.04\u0026ndash;0.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.02\u0026ndash;0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExchangeable Al\u003csup\u003e3+\u003c/sup\u003e cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.03\u0026ndash;0.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eND\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExchange acidity\u003c/p\u003e\u003cp\u003ecmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.11\u0026ndash;0.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.02\u0026ndash;0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAvailable P (Brays I) (mg/kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.25\u0026ndash;11.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.9\u0026ndash;9.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExchangeable Ca\u003csup\u003e2+\u003c/sup\u003e cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.9-7.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.51\u0026ndash;7.41\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFree Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.88\u0026ndash;6.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.13\u0026ndash;7.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCrystalline Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.78\u0026ndash;6.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.00-6.41\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAmorphous Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.10\u0026ndash;0.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.12\u0026ndash;0.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Changes in soil properties after liming\u003c/h2\u003e\u003cp\u003eLime requirement of the soils to pH 6.5 varied from 1515 to 2938 mg/kg. Clay, crystalline Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, amorphous Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, pH\u003csub\u003ew\u003c/sub\u003e, organic carbon and exchangeable Al together determined 99% of variations (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.99) in the LR of the soils but the relationship of the LR with any of the individual soil properties was not significant.\u003c/p\u003e\u003cp\u003eSoil pH increased from 6.3 to 7.1 after liming (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). There was decrease in organic carbon content in soil after liming which might be due to increase in the microbial activities causing an increase in the decomposition of organic matter. Exchange acidity decreased and exchangeable Al was not detected in any of the soils after liming. Exchangeable Ca\u003csup\u003e2+\u003c/sup\u003e content in the soils increased after liming. Ca\u003csup\u003e2+\u003c/sup\u003e added to the soils through liming varied from 1.52 to 2.94 cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Increase in exchangeable Ca\u003csup\u003e2+\u003c/sup\u003e after liming varied from 1.54 to 2.90 cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The lowest increase was in Khajuripada soil which was having the lowest lime requirement of 758 mg pure CaCO\u003csub\u003e3\u003c/sub\u003e/kg (@ 0.5 LR). Exchangeable Ca content in this soil before liming was 5.28 cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The highest increase was in Semiliguda soil, having the highest lime requirement of 1469 mg pure CaCO\u003csub\u003e3\u003c/sub\u003e/kg (@ 0.5 LR). Exchangeable Ca\u003csup\u003e2+\u003c/sup\u003e content in this soil before liming was 4.51 cmol(p\u003csup\u003e+\u003c/sup\u003e) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Available P in soil decreased slightly after liming. All the forms of Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e in soil increased after liming. A part of the amorphous Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e might be slowly organized to crystalline form causing an increase in crystalline and free Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e contents in soil. Increase in all these forms of Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e after liming has also been reported by Majumdar et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Effect of liming on phosphate adsorption:\u003c/h2\u003e\u003cp\u003eEquilibrium concentrations of phosphorous and the amount of P adsorbed increased, whereas per cent P adsorbed decreased in both limed and unlimed soils with increasing concentrations of P-added (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIncrease in P adsorption was due to increasing contacts of phosphate ions with soil. Decrease in per cent adsorption was due to increase in the ionic population of phosphate for adsorption by the same number of adsorption sites. Phosphate adsorption increased slightly after liming. The slight increase in phosphate adsorption might be due to a small increase in amorphous Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e content in the soils after liming. Similar results have also been reported by Anjos and Rowell [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEquilibrium P-concentration and P-adsorbed by the soils before and after liming\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eConc. of\u003c/p\u003e\u003cp\u003eP added\u003c/p\u003e\u003cp\u003e(\u0026micro;g ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eEquilibrium P conc. (\u0026micro;g ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eP adsorbed (\u0026micro;g g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003e% P adsorbed\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBefore liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAfter liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBefore liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAfter liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBefore liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eAfter liming\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.06\u0026ndash;0.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.035\u0026ndash;0.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e64-78.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e68.2\u0026ndash;79.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e80.0-98.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e85.3\u0026ndash;99.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.21\u0026ndash;1.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.185\u0026ndash;1.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e126.6-155.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e135-156.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e79.1\u0026ndash;97.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e84.4\u0026ndash;97.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.56\u0026ndash;2.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.52\u0026ndash;2.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e181.2-228.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e185\u0026ndash;229\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e75.4\u0026ndash;95.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e77.1\u0026ndash;95.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.92\u0026ndash;5.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.90\u0026ndash;5.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e206.4-301.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e215.4-302.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e64.4\u0026ndash;94.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e67.3\u0026ndash;94.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.98\u0026ndash;8.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.90\u0026ndash;6.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e236.8\u0026ndash;361\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e242-362.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e59.2\u0026ndash;90.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e66.9\u0026ndash;90.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.11\u0026ndash;11.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.00-11.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e243.4-417.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e257.4-420.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e50.7\u0026ndash;87.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e53.6\u0026ndash;87.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5.26-14.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4.97\u0026ndash;13.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e280-454.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e295.6-460.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e50-81.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e52.8\u0026ndash;82.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.46\u0026ndash;16.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.05\u0026ndash;15.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e307.4-490.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e319-499.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e48.0-76.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e50.1\u0026ndash;78.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10.88\u0026ndash;20.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10.42\u0026ndash;19.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e313.2-502.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e331.4-511.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43.5\u0026ndash;69.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e46.0-71.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e14.06\u0026ndash;23.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e13.67\u0026ndash;22.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e335.8-518.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e351-526.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e42.0-64.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e43.9\u0026ndash;65.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Change in the distribution coefficient of phosphorus after liming:\u003c/h2\u003e\u003cp\u003eDistribution coefficient (Kd) of phosphorus is the amount of P adsorbed (\u0026micro;g/g) /equilibrium P concentration (\u0026micro;g/ml). It is a simple partition model between the phosphate in the soil solution and in the adsorbed phases. It is used as a measure of phosphate availability by different workers [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Kd values decreased in both limed and unlimed soils with increase in the P-concentration added.\u003c/p\u003e\u003cp\u003eThis was due to the number of times the amount of P adsorbed increased was less than the number of times of the increase in the equilibrium P concentration. Kd values in the limed soils were higher than in the unlimed soils and this difference decreased with increasing concentrations of P added (Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). However, the higher Kd values in the limed than in the unlimed soils indicated increase in the affinity of phosphate to the adsorbed phase than to the solution phase after liming.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eKd of phosphorus before and after liming\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eConc. of\u003c/p\u003e\u003cp\u003eP added\u003c/p\u003e\u003cp\u003e(\u0026micro;g ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eKd (ml g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBefore liming\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAfter liming\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e80-1313.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e115.59-2265.71\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e75.81\u0026ndash;741.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e108.0-844.86\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e61.63-408.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e67.27-440.38\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e36.31-329.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41.19-345.71\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e29.02-182.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e36.67-191.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20.57-134.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23.13-140.27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20.0-86.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22.36\u0026ndash;92.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18.48\u0026ndash;65.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19.96\u0026ndash;70.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15.31\u0026ndash;46.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17.06\u0026ndash;49.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14.43\u0026ndash;36.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15.63\u0026ndash;38.49\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.5 Comparison of the Freundlich and Langmuir equations to describe the phosphate adsorption\u003c/h2\u003e\u003cp\u003eThe P-adsorption data of both limed and unlimed soils could be fitted to both Freundlich and Langmuir equations as indicated by the highly significant positive \u0026lsquo;r\u0026rsquo; values between the dependent and independent variables in the linear forms of these equations.\u003c/p\u003e\u003cp\u003eThe \u0026lsquo;r\u0026rsquo; values were higher in case of Langmuir equation than in the Freundlich equation indicating that the former was better than the latter in describing the phosphate adsorption by both limed and unlimed soils (Table \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u0026lsquo;r\u0026rsquo; values between the dependent and independent variables in the liner forms of the adsorption equations\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eAdsorption equation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e\u003cp\u003e\u0026lsquo;r\u0026rsquo; values\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eAverage\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eAverage\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFreundlich equation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.94** to 0.98**\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e0.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96** to 0.99**\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.97\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLangmuir equation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.97** to 0.99**\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.97** to 0.99**\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe adsorption constants Freundlich K, Langmuir K\u003csub\u003e1\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003e increased after liming, whereas Freundlich \u0026lsquo;n\u0026rsquo; decreased after liming (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eLangmuir K\u003csub\u003e1\u003c/sub\u003e which is the ratio of phosphate adsorption to desorption rate constants increased after liming indicating that phosphate was held more strongly on the clay surface after liming. Langmuir K\u003csub\u003e2\u003c/sub\u003e which is the maximum phosphate adsorption capacity of soil increased slightly after liming. It varied from 370\u0026ndash;544 \u0026micro;g/g in the unlimed soils and from 385 to 550 \u0026micro;g/g in the limed soils. The ΔG\u003csup\u003e0\u003c/sup\u003e values of phosphate adsorption decreased after liming which is due to increase in Langmuir K\u003csub\u003e1\u003c/sub\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFreundlich and Langmuir adsorption constants and their changes after liming\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAdsorption constant\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAL\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFreundlich K(\u0026micro;g/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e88.9 to 220.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e105.9 to 257.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFreundlich n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.280 to 0.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.270 to 0.464\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLangmuir K\u003csub\u003e1\u003c/sub\u003e(ml/\u0026micro;g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.186 to 3.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.254 to 3.70\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLangmuir K\u003csub\u003e2\u003c/sub\u003e(\u0026micro;g/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e370.4 to 543.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e384.6 to 549.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e∆G\u003csup\u003e0\u003c/sup\u003e of P-adsorption (cal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-664 to 996\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-775 to 812\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMPBC(ml/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e87.3 to 1457.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e120.4 to 1474.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.6 Change in the equilibrium and maximum phosphate buffering capacities of the soils after liming\u003c/h2\u003e\u003cp\u003eEquilibrium phosphate buffering capacity of soil indicates the change in the amount of P adsorbed (x/m) per unit change in equilibrium P concentration and is a function of phosphate saturation in soil. In both limed and unlimed soils, EPBC decreased with increasing concentrations of P-added due to increasing P-saturation in soil (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). It increased after liming due to increase in both Langmuir K\u003csub\u003e1\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003e and decrease in equilibrium P concentration.\u003c/p\u003e\u003cp\u003eMaximum phosphate buffering capacity (MPBC) is the change in the amount of P-adsorbed per unit change in its equilibrium concentration when phosphate saturation in soil is negligible and almost all the adsorption sites are free for phosphate adsorption. It is a fundamental property of soil which integrates both intensive (K\u003csub\u003e1\u003c/sub\u003e) and extensive (K\u003csub\u003e2\u003c/sub\u003e) properties of soil and is independent of nutrient saturation in soil [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. After liming MPBC of all the soils increased. It varied from 83 to 1457 ml/g in the unlimed soils and 120 to 1475 ml/g in the limed soils (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Increase in MPBC after liming was due to increase in both Langmuir K\u003csub\u003e1\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003e. MPBC possessed a strong positive correlation with Langmuir K\u003csub\u003e1\u003c/sub\u003e (r\u0026thinsp;=\u0026thinsp;0.97**) in both unlimed and limed soils. With increase in K\u003csub\u003e1\u003c/sub\u003e, binding strength of the adsorbed phosphate on the clay surface increases and its desorption to the soil solution decreases to increase the MPBC. It was negatively correlated with ∆G\u003csup\u003e0\u003c/sup\u003e (r= -0.94**) in both unlimed and limed soils.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of lime on the EPBC and supply parameter of phosphate in soils\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eConc. of P added (\u0026micro;g ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eEPBC (ml/g)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eSupply parameter\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eBL\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAL\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.2\u0026mdash;559.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e94.8-614.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.43\u0026ndash;2.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.33\u0026ndash;1.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e36.8-380.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e50.5-485.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.1\u0026ndash;4.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.93\u0026ndash;3.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9.7-234.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13.2-257.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.2\u0026ndash;7.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.9\u0026ndash;6.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.82\u0026ndash;148.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.1-155.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.3\u0026ndash;10.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.8\u0026ndash;9.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.4\u0026ndash;56.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.6\u0026ndash;57.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.3\u0026ndash;14.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.6\u0026ndash;12.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.68\u0026ndash;28.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.96\u0026ndash;28.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7.1\u0026ndash;17.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.2\u0026ndash;15.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.49\u0026ndash;12.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.68\u0026ndash;12.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e9.3\u0026ndash;20.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.3\u0026ndash;18.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.35\u0026ndash;8.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.47\u0026ndash;8.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e11.2\u0026ndash;23.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e10.3\u0026ndash;21.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.24\u0026ndash;6.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.32\u0026ndash;6.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e12.9\u0026ndash;26.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e12.7\u0026ndash;24.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.18\u0026ndash;5.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.242-5.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.4\u0026ndash;29.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13.4\u0026ndash;27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.7 Change in supply parameter of phosphorus with liming\u003c/h2\u003e\u003cp\u003eSupply parameter integrates the effect of quantity, intensity and buffering capacity of phosphate on P-supply from the adsorbed surface to the plant root [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. It increased with increasing concentrations of P- added in both limed and unlimed soils due to increase in both x/m and Ce values (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). It decreased in all the soils after liming which was due to increase in both Langmuir K\u003csub\u003e1\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAcid soils of Odisha belonging to Alfisols are low in available P. Increase in equilibrium buffering capacity, maximum buffering capacity and decrease in P supply parameter after limimg indicated that availability of the adsorbed phosphate in limed soils will continue for a longer period although its immediate availability decreases as compared to the unlimed soils. This may necessitate to apply a higher dose of P in these soils after liming to increase the crop yield.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003e\u003cstrong\u003eEthics, consent to participate and consent to publish declaration\u003c/strong\u003e\u003c/h2\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that there is no competing interest exists.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThe authors received no specific funding for this research.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eConceptualization; DS, PKD., Methodology; DS., PKD., Analysis; DS., Writing original draft preparation; PM., PKD., Writing, review and editing; PM; BKS., Supervision; PKD\u003c/p\u003e\n\u003ch2\u003eAcknowledgement\u003c/h2\u003e\n\u003cp\u003eThis experiment was supported by the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Siksha \u0026lsquo;O\u0026rsquo; Anusandhan Deemed to be University, Bhubaneswar, Odisha, India. The authors acknowledge all the necessary support provided during the study\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eThe data are available within the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLin C, Busscher WJ, Douglas LA. Multifactor kinetics of phosphate reactions with minerals in acidic soils modelling and simulation.Soil. Sci Soc Am J. 1983;47:1097\u0026ndash;103.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHayens RJ. Effect of lime and phosphate applications on the adsorption of phosphate, sulfate and molybdate by a spodosol. Soil Sci. 1982;135:221\u0026ndash;3.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePaliyal SS, Verma TS. Adsorption of added phosphorus as influenced by the application of lime and gypsum in an acid Alfisol of Himalaya Region. J Indian Soc Soil Sci. 2002;50:163\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMajumdar B, Kumar K, Venkatesh MS, Patiram. Effect of liming on phosphorous adsorption and desorption behaviour of acidic Alfisols and Entisols of Meghalaya. J Indian Soc Soil Sci. 2005;53(2):188\u0026ndash;93.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHolford ICR, Scheirtzer BE, Crocker GJ. Long- term effects of lime in soil phosphorus solubility and sorption in light acidic soils. Aust J Soil Res. 1994;32:795\u0026ndash;805.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMora ML, Balza G, Pizarro C, Demanet R. Effect of calcitic and dolomitic lime on physicochemical properties of a chilean Andisol. Commun Soil Sci Plant Anal. 1999;30:427\u0026ndash;39.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSanyal SK, Datta. SK. Chemistry of phosphorus transformations in soil. Advances in Soil Science.1991; 16: 1-120.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHayens RJ. Lime and phosphate in soil-plant system. Adv Agron. 1984;37:249\u0026ndash;315.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSmyth TJ, Sanchez PA. Effects of lime, silicate and phosphorus applications to an Oxisol on phosphorus sorption and iron retention. Soil Sci Soc Am J. 1980;44:500\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eReeve NG, Sumner ME. Effect of aluminium toxicity and phosphorus fixation on crop growth on Oxisols in Natural.Soil Science Society of America Proceeding. 1970; 34: 263\u0026ndash;267.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eArias JS, Fernandez PG. Changes in phosphorus adsorption in a Palexerult amended with limestone and/or gypsum. Commun Soil Sci Plant Anal. 2001;32(5\u0026ndash;6):751\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAnjos JT, Rowell DL. The effect of lime on phosphorus adsorption and barley growth in three acid soils. Plant Soil. 1987;103:75\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJackson ML. Soil chemical Analysis. New Delhi: Prentice Hall of India Private Limited; 1956.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShuman LM. Separating soil iron and manganese-oxide fractions for microelement analysis. Soil Sci Soc Am J. 1982;46:1099\u0026ndash;102.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJackson ML. Soil chemical Analysis. New Delhi: Prentice Hall of India Private Limited; 1973.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBrown J, Cisco JR. An improved Woodruff buffer for estimation of lime requirements. Soil Sci Soc Am J. 1984;48:587\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMurphy J, Riley JP. A modified single solution method for the determination of phosphate in natural waters. Anal Chem Acta. 1962;27:31\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTomar NK, Gautam KK. Effect of soil properties on hydrolysis of ammonium polyphosphate and tetrapotassium pyrophosphate in some arid and semiarid soils. Arid Soil Res Rehabil. 1996;10(1):43\u0026ndash;51.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHolford ICR, Mattingly GEG. A model for the behaviour of labile phosphate in soil. Plant Soil. 1976;44:219\u0026ndash;29.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKhasawneh FE. Solution ion activity and plant growth. Soil Science Society of America Proceeding 35: 426\u0026ndash;436 (1971).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Liming, Phosphate adsorption, Freundlich and Langmuir equations, Equilibrium and maximum phosphate buffering capacity, Phosphate supply parameter","lastPublishedDoi":"10.21203/rs.3.rs-7828814/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7828814/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eEffect of liming on phosphate adsorption was studied in the Alfisols of Odisha. The soils were loamy sand to sandy clay loam in texture, strongly to moderately acidic, low to medium in organic carbon and low in available P contents. There was slight increase in phosphate adsorption by the soils after liming. Langmuir equation was slightly better than the Freundlich equation in describing phosphate adsorption by both limed and unlimed soils. Langmuir bonding energy constant, adsorption maxima, equilibrium and maximum phosphate buffering capacities increased, whereas ΔG\u003csup\u003e0\u003c/sup\u003e of phosphate adsorption and supply parameter of phosphate decreased after liming. Freundlich K increased, whereas Freundlich n decreased after liming.\u003c/p\u003e","manuscriptTitle":"Effect of Liming on Phosphate Adsorption Characteristics in the Alfisols of Odisha","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-18 20:24:21","doi":"10.21203/rs.3.rs-7828814/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7926632c-b202-42af-8598-8a2eda4595e8","owner":[],"postedDate":"November 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-28T09:52:39+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-18 20:24:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7828814","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7828814","identity":"rs-7828814","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}