Nutrient Losses Through Surface Runoff in Different Soil Conservation Practices in Mid Elvation Tea Lands in Sri Lanka: Implications for Climate Change Adaptation

Nutrient Losses Through Surface Runoff in Different Soil Conservation Practices in Mid Elvation Tea Lands in Sri Lanka: Implications for Climate Change Adaptation | 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 Nutrient Losses Through Surface Runoff in Different Soil Conservation Practices in Mid Elvation Tea Lands in Sri Lanka: Implications for Climate Change Adaptation L A S P Jayasinghe, Simplicio M. Medina This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8498265/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Soil nutrient loss occurs naturally through soil erosion, runoff, leaching and burning of crop residues, but this process has accelerated due to improper land and crop management. Minimizing of nutrient loss is crucial under the climate change, especially in steep agricultural lands. This study was conducted to evaluate the effectiveness of soil conservation measures in reducing nutrient loss in a mature tea field at Kenilworth Estate, Ginigathhena, Sri Lanka (6°59' N, 80°29' E), located at mid-elevation. The slope of the study area was 60–72%. Erosion plots were arranged in Randomized Complete Block Design with four treatments; stone terrace (T), stone terrace with Vetiver grass (TV), terrace wall (TW) as soil conservation measures (SCM), and tea without conservation (TO) as control. Runoff were collected to the sediment tanks attached to the plots to analyze nutrients; Available Nitrogen (AN), Available Phosphorous (AP) and Available Potassium (AK) from October 2020 to November 2021 with 5970 mm rainfall. The NO 3 - -N concentration in runoff was not significant in different SCMs and NH 4 + -N concentration in runoff was significantly low in TV. The NH 4 + -N and NO 3 - -N removal in TV was 1.3 and 0.8 kg ha -1 yr -1 respectively. The amount of AP removed by runoff was significantly higher in TO (2.1 kg ha -1 yr -1 ) and 0.9,0.5,0.4 kg ha -1 yr -1 in T, TV, TW respectively. AK loss through runoff was not significant among treatment and lower in SCMs. TV was the most effective nutrient saving measure, reducing AN, AP and AK losses by 6.9 (78%), 1.7 (80%) and 7.8 (86%) kg ha -1 yr -1 respectively due to combination of physical and biological measures. Climate change Nutrient loss soil conservation soil erosion steep agriculture Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Application of fertilizer in tea cultivation is widely practiced to improve yield, productivity and quality ( 17 ). At present, fertilizer use is one of the most expensive management practices in tea plantation ( 18 ) and the major nutrients required for tea; nitrogen, phosphorus, and potassium and calcium, magnesium, zinc, sulfur and other micronutrients are also supplied to tea as synthetic fertilizer. In general, nutrient removal is common phenomenon and it has accelerated through improper land and crop management, crop harvest, soil erosion, surface runoff, leaching and burning of crop residues. Surface runoff and soil erosion are the primary pathways of nitrogen and phosphorus loss from agricultural soil ( 9 ). Therefore, reducing surface runoff and soil erosion by implementing soil conservation measures is an effective way to control nutrient loss through surface water ( 4 ). Tea ( Camellia sinensis ) is planted in mostly steep lands of up and mid elevations in central highlands of Sri Lanka. Aside from crop harvesting, soil erosion and runoff are the common natural phenomena causing nutrient removal from the tea lands. Climate, particularly from rainfall with high intensity and amount ( 23 ), and during the monsoon season, is a significant factor that increases erosion ( 7 ). Topography affects erosion both in terms of concavity or convexity, but also terms of slope length and slope angle. Runoff increases with steeper slopes and convex slopes have a higher risk on erosion than concave. Also, soil texture, organic matter, macro porosity, compaction and infiltration are soil properties that affect soil erosion and runoff ( 2 ). Apart from above, previous research data in China has indicated that over 30% of tea plantation management applies excessive chemical fertilizers to boost yield, leading to huge nutrient imbalances in tea land ( 15 ). Annual recommended nutrient amounts for tea in mid- country, Sri Lanka are 270–400 N Kg/ ha, 35 P Kg/ha and 100–140 K Kg/ha (2. According to the reported data, it was estimated that 86% of the nitrogen fertilizer was discharged into the river water out of applied 620 kg ha − 1 year − 1 of nitrogen, while 38% as for the phosphorus out of applied 55 kg ha − 1 year − 1 in Japan tea lands ( 24 ). Soil conservation measures application is one of the effective methods to reduce soil erosion and runoff as on farm practices. The volume of runoff was reduced by 80% in terrace with Vetiver grass strip followed by 68% in terrace wall and 55% in terrace, compared to no conservation treatment in mid elevation tea lands in Sri Lanka ( 12 ). Contour planting is one of agronomic measure for soil and moisture conservation practiced in agricultural system. There are research evidences in several cropping systems in Brazil that runoff under natural precipitation, planting in the direction of the slope and planting along the contour. showed runoff 25.6 cm and 9.9 cm respectively, in the direction of slope and planted along the contour ( 13 ). The nutrients present in the agriculture land, either from inherent soil fertility or from fertilizer application, are removed mainly by runoff water. Amarasekera et al, ( 1 ) reported that higher amount of rainwater interception in tea plantation due to well canopy cover and available nitrogen and available phosphorus in surface runoff may not contributed to the water pollution. Loss of nutrient directly affected to the cost of production due to extra application of essential synthetics fertilizers. Therefore, reduction of nutrient losses is most important to secure environment and sustainable tea land management. Though, there are many studies to quantify the soil loss, there are no sufficient recent studies to measure the nutrient removal from tea fields through runoff water. Not only tea industry agriculture sector in the world is also facing challenges of climate change such as high intensity rainfall, temperature changes etc. Hence, the main objective of this study is to quantify the available macro nutrients removed through runoff under different soil conservation measures. Methodology Experimental Site The study area was in Kenilworth estate, Ginigathhena, Sri Lanka (6°59' north latitude; 80°29' east longitude), located at the mid elevation with altitude ranging from 580 to 600m amsl. Its agro-ecological zone is wet zone mid country (WM1a) with 75% annual rainfall expectancy, or more than 3200mm rainfall ( 16 , 19 ). The experiment was set in slope range of 60%-72%. Soil series is Maskeliya soil series and the tea cultivar used was TRI 2023. Establishment of Experimental Plots were established along the contours and the plot area was about 30m 2 . Aluminum sheet (gauge 28), was used to cover the plots and buried into soil to avoid the inflow and outflow of run-off water from the experimental plots as described by Hudson, 1993. Plastic barrels with 250 liters capacity were used as runoff water collecting tanks connected by the pipe in the middle of lower end of each plot to ensure all run-off water flow to the tank. There was an opening with a lid on the plastic barrel to collect samples and discharge runoff water. Four soil conservation measures (treatments) were established by randomizing within the blocks. Statistical design applied for the experiment was RCBD and the SAS statistical package and ANOVA procedure were used for data analysis. Treatments are as follows; Stone terrace (T) Stone terrace with vetiver grass (TV) Terrace wall (TW) Tea only land (TO) Stone terrace used in tea plantations are built up to the height of the soil surface with its width at 45cms. Vetiver grasses were planted closer to the inner edge of the terrace, was the stone terrace with vetiver grass treatment. Terrace wall is also called stone bund that is built similar to the stone terrace where the height of the terrace wall is 30cms above the soil surface and width was similar to terrace ( 21 ). The tea only treatment is the tea plot without soil conservation measures. Data Collection and Data Analysis Data collecting period was from October 2020 to November 2021. Runoff water collected in collecting tanks was measured according to the rain events or filled with tank volume. Rainfall data were recorded from the automated weather station installed in the field. Method of sampling for small scale plots has been described by Schuman et al., ( 20 ), Hudson ( 11 ) and Hansen ( 10 ), where water in sediment tanks was mixed thoroughly for 2–3 minutes to dissolve all sediment and soil particles attached to tank wall, using long arm brush. After mixing, about 300ml sample was collected within 10 seconds, from bottom of the tank. Collected runoff water samples were kept to settle and prepared for chemical analysis after filtering. Sub-sample of filtered runoff water was stored in a freezer for determination of available nitrogen (distillation method), available phosphorus (Colorimetric method) and available potassium (Flame photometry method). RESULTS AND DISCUSSION Soil Fertility Status in Tea Field Soil fertility is the ability or capacity of the soil to supply sufficient quantities and proportions of essential plant nutrients required for optimal growth of specified plants as governed by the chemical, physical and biological attributes. (FAO, n d). Soil texture analysis showed sand, clay and silt as 54.8%, 36.3% and 9.1% respectively, making the soil sandy clay in this site. The average bulk density (BD) of soil in the site was 1.48 g/cm 3 . This indicates that the soil is not compacted and have more porous soil. pH of soil was 4.62, which is within the range of 4.5 to 5.5, that is preferable for healthy tea plant growth. Soil organic carbon (OC) is one of the major components in soil fertility, but OC content in the field was comparatively low at 0.7%. Total nitrogen was 0.15%, also comparatively lower than the optimum level of 0.2–0.3%. All exchangeable cations (K, Na, Mg, Ca) were quantitatively lower than the optimal level for tea. Obtained results has shown that chemical and physical conditions of soil in this study area is not in favorable level. It may be due to the various reasons such as climate and vegetation, topography, leaching, wash off and poor land management practices. Runoff Variation in Different Soil Conservation Measures (SCM) Rainfall received and runoff discharge from different soil conservation measures during the study period is shown in Fig. 1 . Total rainfall from October 2020 to November 2021 was 5970 mm. In this study, the amount of runoff discharged from the land with SCMs has changed with the changes of the amount of rainfall received. The pattern of the runoff discharge has varied in continuous heavy rainy (October and November) period. If rainfall is received continuously, soil will saturate and results to increased surface runoff. Furthermore, there were several peaks in rainfall and it has been clearly shown that discharged volume was high in all treatments at peak rainfall events. However, runoff in TO registered significantly higher values compared to the other soil conservation treatments and there is no significant difference among the SCM treatments. Total runoff of T, TV, TW and TO throughout the study period was 753.5 m 3 ha − 1 yr − 1 , 332.9 m 3 ha − 1 yr − 1 , 535.7 m 3 ha − 1 yr − 1 and 1681.8 m 3 ha − 1 yr − 1 respectively. There are many key factors influencing surface runoff such as soil type and compaction, vegetation, slope and rainfall intensity etc. This experimental site, sandy clay with less compacted and fully ground cover with mature tea plants are favorable factors to higher absorption of rainfall to soil. Nutrient Loss Through Surface Runoff The soil is naturally rich in nutrients and in tea plantation, additional nutrients as a mixture are provided as required to fulfill the gap of nutrients in soil due to nutrients remove through frequent harvesting of leaves and soil erosion and washed off etc. Also, supplied nutrients are either absorbed by plants, fixed in soil and leached. Accordingly, available nitrogen (AN), available phosphorus (AP) and available potassium (AK) were analyzed in the runoff water to determine the amount of nutrient removed with runoff. Available Nitrogen The amount of available nitrogen removed by runoff is shown in Fig. 2 . While NH 4 -N and NO 3 -N concentration (mg/l) of runoff water was not significant among the treatments, higher in the SCMs and lower in TO. The runoff NH 4 -N and NO 3 -N concentrations ranged from 3.2–3.9 mg l − 1 and 2.1 to 2.3 mg l − 1 respectively. The N concentrations in China tea land ranged from 4.4 to 17.4 mg l − 1 under the application of 240 N kg ha − 1 yr − 1 (Ni, K et al., 2019). Similar to China, high nitrate concentrations as much as about 50mg l − 1 in river and reservoir water were reported in a tea field in Japan ( 14 ). While the rate of NH4-N and NO3-N losses was not significant, the total amount of losses was significant. TV have shown the lowest amount of NH 4 -N in runoff water and NO 3 -N, its behavior was similar to that of the NH 4 -N. The next lowest amount of NH 4 -N and NO 3 -N in runoff water showed in TW. Soil conservation methods have significantly reduced the removal of AN compared to the TO. The amount of NH 4 -N and NO 3 -N removal in TV was 1.3 and 0.8 kg ha − 1 yr − 1 respectively. Available Phosphorus Available phosphorus (AP) is an essential nutrient for tea cultivation, and phosphate fertilizers are commonly applied to meet crop nutrient requirements and to increase tea production. However, phosphorus loss through surface runoff can contribute to aquatic eutrophication, posing a serious threat to environmental safety. Available Phosphorus (AP) changes in SCM are shown in Fig. 3 . The results show that there was no significant difference in the rate and amount of AP removal through surface runoff between SCMs and TO treatments. The AP removal rate was in the range of 0.88 mg/l – 1.26 mg/l. Considering of amount of AP removal was in range from 0.42 kg ha − 1 yr − 1 to 2.1 kg ha − 1 yr − 1 . The lowest AP showed in TV (0.42 kg ha − 1 yr − 1 ) followed by TW (0.51 kg ha − 1 yr − 1 ). According to the research done by other countries, only a fraction of applied phosphorus for tea is typically taken up by tea plants, with large proportions retained in soil or lost in runoff and erosion. One study in Taiwan found that less than 5% of applied phosphorus was exported in storm runoff, while the majority persisted in the soil pool, indicating that improving fertilizer use efficiency is key to reducing environmental loss ( 6 ). Similarly, the results of this study showed that AP losses were not significantly different among treatments. And AP loss is 1.1–2.7% of applied phosphorus (35 kg/ha/yr) under the SCM treatments and 6.7% under the TO. The most applied phosphorus was either retained in the soil or taken up by tea plants, which is consistent with previous findings that phosphorus in tea-growing soils is strongly adsorbed by soil minerals and organic matter. Available Potassium (K) Potassium (K) is a major nutrient in tea but K losses in runoff have been given less attention than N and P, not only tea land but also in most crop due to K is considered as less or not threat element to water and environmental quality. The available potassium (AK) is that readily uptake to the plant. The concentration (rate) and amount in runoff water are shown in Fig. 4 . It has been shown that there is no significant difference in potassium concentration between TO and the SCM’s and also among the SCM’s. When calculating amount of potassium per hectare, the amount varied between 1.27 and 9.5 kg ha − 1 yr − 1 . However, the removal of potassium from the SCMs with runoff water was significantly lower compared to the TO. The lowest amount (1.27 kg ha − 1 yr − 1 ) of potassium removal was observed in TV soil conservation treatment. The significantly better conservation of the soil nutrients showed vetiver planted on bund resulting in the soil fertility build-up in crop land in India ( 8 ). In the research on several cropping system, the K loss with runoff was 0.5 kg K ha − 1 in crop planted along the contour and planted in along the slope was 3.2 kg K ha − 1 (Leite, 2018). Tea planting is also done in the contour as agronomic soil conservation method and convenient for cultural practices. This is also positively support to reduce surface runoff and nutrient loss. Conclusion The results of the study demonstrate that nutrient removal from tea land is closely proportional to the volume of runoff water discharged. Established soil conservation measures have significantly reduced the removal of available nitrogen compared to tea only treatment. Among the SCMs, terrace with vetiver grass showed the lowest AN losses with NH₄⁺-N and NO₃⁻-N removal 1.3 and 0.8 kg ha − 1 yr − 1 . Rate of available phosphorus and available potassium removal was more or less similar across all treatments and available phosphorus loss by runoff was 0.42 kg ha − 1 yr − 1 in terrace with vetiver grass. Similarly, the lowest amount of available potassium removal was observed in terrace with vetiver grass (1.27 kg ha − 1 yr − 1 ) soil conservation measures. TV was identified the most effective nutrient saving measure, due to reducing AN, AP and AK losses by 6.9 (78%), 1.62 (80%) and 7.8 (86%) kg ha − 1 yr − 1 respectively compare to tea only. Combination of SCM has been applied to conserve soil and moisture in tea land, where terrace is physical/ mechanical measure to reduce flow rate of runoff and strips of vetiver grass provide biological barriers to retain small soil particle flow through runoff water. In conclusion, combination of physical and biological soil conservation measures is highly effective for nutrient saving that removal through surface runoff. Among the treatment in this study TV the most effective SCM and followed by terrace wall for steep tea lands. Declarations Author Contribution L.A.S.P. Jayasinghe conducted the research, carried out data collection, performed data analysis, and wrote the main manuscript. Simplicio M. 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08:57:51","extension":"html","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":58996,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/4743306ec14bb43f0f7b16eb.html"},{"id":99795551,"identity":"d91aa8c6-14a1-4caf-8260-a2e757136047","added_by":"auto","created_at":"2026-01-08 13:38:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":135707,"visible":true,"origin":"","legend":"\u003cp\u003eRainfall and runoff variation during the study period\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/61161640b016787b26551f3b.png"},{"id":99682107,"identity":"4c9a356c-15cf-4ae1-92fa-3c556ff6dd6f","added_by":"auto","created_at":"2026-01-07 08:57:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":24020,"visible":true,"origin":"","legend":"\u003cp\u003eAvailable nitrogen loss through surface runoff water\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/472ee3c16ac99108c5f1e75d.png"},{"id":99682108,"identity":"41e0256c-7d3e-491a-865b-feff68f629d9","added_by":"auto","created_at":"2026-01-07 08:57:51","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":28731,"visible":true,"origin":"","legend":"\u003cp\u003eAvailable phosphorus loss through surface runoff water\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/85e26a6cc681ba1b2cb64b81.png"},{"id":99794870,"identity":"2dd788a3-b1d3-45e2-bed4-67408d6615fe","added_by":"auto","created_at":"2026-01-08 13:36:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":25631,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAvailable Potassium loss through surface runoff water\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/c65a0dab42c0ade0553e1d2a.png"},{"id":99805057,"identity":"83abb01f-5ee7-4e21-9abe-a7a104adc7a3","added_by":"auto","created_at":"2026-01-08 14:15:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":642590,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8498265/v1/62ed5830-4d8d-4097-a5b6-e2c480fb24a1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eNutrient Losses Through Surface Runoff in Different Soil Conservation Practices in Mid Elvation Tea Lands in Sri Lanka: Implications for Climate Change Adaptation\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eApplication of fertilizer in tea cultivation is widely practiced to improve yield, productivity and quality (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). At present, fertilizer use is one of the most expensive management practices in tea plantation (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e) and the major nutrients required for tea; nitrogen, phosphorus, and potassium and calcium, magnesium, zinc, sulfur and other micronutrients are also supplied to tea as synthetic fertilizer. In general, nutrient removal is common phenomenon and it has accelerated through improper land and crop management, crop harvest, soil erosion, surface runoff, leaching and burning of crop residues. Surface runoff and soil erosion are the primary pathways of nitrogen and phosphorus loss from agricultural soil (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). Therefore, reducing surface runoff and soil erosion by implementing soil conservation measures is an effective way to control nutrient loss through surface water (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTea (\u003cem\u003eCamellia sinensis\u003c/em\u003e) is planted in mostly steep lands of up and mid elevations in central highlands of Sri Lanka. Aside from crop harvesting, soil erosion and runoff are the common natural phenomena causing nutrient removal from the tea lands. Climate, particularly from rainfall with high intensity and amount (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e), and during the monsoon season, is a significant factor that increases erosion (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Topography affects erosion both in terms of concavity or convexity, but also terms of slope length and slope angle. Runoff increases with steeper slopes and convex slopes have a higher risk on erosion than concave. Also, soil texture, organic matter, macro porosity, compaction and infiltration are soil properties that affect soil erosion and runoff (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Apart from above, previous research data in China has indicated that over 30% of tea plantation management applies excessive chemical fertilizers to boost yield, leading to huge nutrient imbalances in tea land (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Annual recommended nutrient amounts for tea in mid- country, Sri Lanka are 270\u0026ndash;400 N Kg/ ha, 35 P Kg/ha and 100\u0026ndash;140 K Kg/ha (2. According to the reported data, it was estimated that 86% of the nitrogen fertilizer was discharged into the river water out of applied 620 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyear\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of nitrogen, while 38% as for the phosphorus out of applied 55 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyear\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in Japan tea lands (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSoil conservation measures application is one of the effective methods to reduce soil erosion and runoff as on farm practices. The volume of runoff was reduced by 80% in terrace with Vetiver grass strip followed by 68% in terrace wall and 55% in terrace, compared to no conservation treatment in mid elevation tea lands in Sri Lanka (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Contour planting is one of agronomic measure for soil and moisture conservation practiced in agricultural system. There are research evidences in several cropping systems in Brazil that runoff under natural precipitation, planting in the direction of the slope and planting along the contour. showed runoff 25.6 cm and 9.9 cm respectively, in the direction of slope and planted along the contour (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). The nutrients present in the agriculture land, either from inherent soil fertility or from fertilizer application, are removed mainly by runoff water. Amarasekera et al, (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) reported that higher amount of rainwater interception in tea plantation due to well canopy cover and available nitrogen and available phosphorus in surface runoff may not contributed to the water pollution. Loss of nutrient directly affected to the cost of production due to extra application of essential synthetics fertilizers. Therefore, reduction of nutrient losses is most important to secure environment and sustainable tea land management.\u003c/p\u003e \u003cp\u003eThough, there are many studies to quantify the soil loss, there are no sufficient recent studies to measure the nutrient removal from tea fields through runoff water. Not only tea industry agriculture sector in the world is also facing challenges of climate change such as high intensity rainfall, temperature changes etc. Hence, the main objective of this study is to quantify the available macro nutrients removed through runoff under different soil conservation measures.\u003c/p\u003e"},{"header":"Methodology","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eExperimental Site\u003c/h2\u003e \u003cp\u003eThe study area was in Kenilworth estate, Ginigathhena, Sri Lanka (6\u0026deg;59' north latitude; 80\u0026deg;29' east longitude), located at the mid elevation with altitude ranging from 580 to 600m amsl. Its agro-ecological zone is wet zone mid country (WM1a) with 75% annual rainfall expectancy, or more than 3200mm rainfall (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). The experiment was set in slope range of 60%-72%. Soil series is Maskeliya soil series and the tea cultivar used was TRI 2023.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEstablishment of Experimental\u003c/h3\u003e\n\u003cp\u003ePlots were established along the contours and the plot area was about 30m\u003csup\u003e2\u003c/sup\u003e. Aluminum sheet (gauge 28), was used to cover the plots and buried into soil to avoid the inflow and outflow of run-off water from the experimental plots as described by Hudson, 1993. Plastic barrels with 250 liters capacity were used as runoff water collecting tanks connected by the pipe in the middle of lower end of each plot to ensure all run-off water flow to the tank. There was an opening with a lid on the plastic barrel to collect samples and discharge runoff water. Four soil conservation measures (treatments) were established by randomizing within the blocks. Statistical design applied for the experiment was RCBD and the SAS statistical package and ANOVA procedure were used for data analysis. Treatments are as follows;\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eStone terrace (T)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eStone terrace with vetiver grass (TV)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eTerrace wall (TW)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eTea only land (TO)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eStone terrace used in tea plantations are built up to the height of the soil surface with its width at 45cms. Vetiver grasses were planted closer to the inner edge of the terrace, was the stone terrace with vetiver grass treatment. Terrace wall is also called stone bund that is built similar to the stone terrace where the height of the terrace wall is 30cms above the soil surface and width was similar to terrace (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). The tea only treatment is the tea plot without soil conservation measures.\u003c/p\u003e\n\u003ch3\u003eData Collection and Data Analysis\u003c/h3\u003e\n\u003cp\u003eData collecting period was from October 2020 to November 2021. Runoff water collected in collecting tanks was measured according to the rain events or filled with tank volume. Rainfall data were recorded from the automated weather station installed in the field. Method of sampling for small scale plots has been described by Schuman et al., (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e), Hudson (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e) and Hansen (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e), where water in sediment tanks was mixed thoroughly for 2\u0026ndash;3 minutes to dissolve all sediment and soil particles attached to tank wall, using long arm brush. After mixing, about 300ml sample was collected within 10 seconds, from bottom of the tank. Collected runoff water samples were kept to settle and prepared for chemical analysis after filtering. Sub-sample of filtered runoff water was stored in a freezer for determination of available nitrogen (distillation method), available phosphorus (Colorimetric method) and available potassium (Flame photometry method).\u003c/p\u003e"},{"header":"RESULTS AND DISCUSSION","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eSoil Fertility Status in Tea Field\u003c/h2\u003e \u003cp\u003eSoil fertility is the ability or capacity of the soil to supply sufficient quantities and proportions of essential plant nutrients required for optimal growth of specified plants as governed by the chemical, physical and biological attributes. (FAO, n d). Soil texture analysis showed sand, clay and silt as 54.8%, 36.3% and 9.1% respectively, making the soil sandy clay in this site. The average bulk density (BD) of soil in the site was 1.48 g/cm\u003csup\u003e3\u003c/sup\u003e. This indicates that the soil is not compacted and have more porous soil. pH of soil was 4.62, which is within the range of 4.5 to 5.5, that is preferable for healthy tea plant growth. Soil organic carbon (OC) is one of the major components in soil fertility, but OC content in the field was comparatively low at 0.7%. Total nitrogen was 0.15%, also comparatively lower than the optimum level of 0.2\u0026ndash;0.3%. All exchangeable cations (K, Na, Mg, Ca) were quantitatively lower than the optimal level for tea. Obtained results has shown that chemical and physical conditions of soil in this study area is not in favorable level. It may be due to the various reasons such as climate and vegetation, topography, leaching, wash off and poor land management practices.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eRunoff Variation in Different Soil Conservation Measures (SCM)\u003c/h2\u003e \u003cp\u003eRainfall received and runoff discharge from different soil conservation measures during the study period is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Total rainfall from October 2020 to November 2021 was 5970 mm. In this study, the amount of runoff discharged from the land with SCMs has changed with the changes of the amount of rainfall received. The pattern of the runoff discharge has varied in continuous heavy rainy (October and November) period. If rainfall is received continuously, soil will saturate and results to increased surface runoff. Furthermore, there were several peaks in rainfall and it has been clearly shown that discharged volume was high in all treatments at peak rainfall events. However, runoff in TO registered significantly higher values compared to the other soil conservation treatments and there is no significant difference among the SCM treatments. Total runoff of T, TV, TW and TO throughout the study period was 753.5 m\u003csup\u003e3\u003c/sup\u003e ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 332.9 m\u003csup\u003e3\u003c/sup\u003e ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 535.7 m\u003csup\u003e3\u003c/sup\u003e ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 1681.8 m\u003csup\u003e3\u003c/sup\u003e ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e respectively. There are many key factors influencing surface runoff such as soil type and compaction, vegetation, slope and rainfall intensity etc. This experimental site, sandy clay with less compacted and fully ground cover with mature tea plants are favorable factors to higher absorption of rainfall to soil.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eNutrient Loss Through Surface Runoff\u003c/h2\u003e \u003cp\u003eThe soil is naturally rich in nutrients and in tea plantation, additional nutrients as a mixture are provided as required to fulfill the gap of nutrients in soil due to nutrients remove through frequent harvesting of leaves and soil erosion and washed off etc. Also, supplied nutrients are either absorbed by plants, fixed in soil and leached. Accordingly, available nitrogen (AN), available phosphorus (AP) and available potassium (AK) were analyzed in the runoff water to determine the amount of nutrient removed with runoff.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eAvailable Nitrogen\u003c/h2\u003e \u003cp\u003eThe amount of available nitrogen removed by runoff is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. While NH\u003csub\u003e4\u003c/sub\u003e-N and NO\u003csub\u003e3\u003c/sub\u003e-N concentration (mg/l) of runoff water was not significant among the treatments, higher in the SCMs and lower in TO. The runoff NH\u003csub\u003e4\u003c/sub\u003e-N and NO\u003csub\u003e3\u003c/sub\u003e-N concentrations ranged from 3.2\u0026ndash;3.9 mg l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 2.1 to 2.3 mg l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e respectively. The N concentrations in China tea land ranged from 4.4 to 17.4 mg l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e under the application of 240 N kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Ni, K et al., 2019). Similar to China, high nitrate concentrations as much as about 50mg l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in river and reservoir water were reported in a tea field in Japan (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). While the rate of NH4-N and NO3-N losses was not significant, the total amount of losses was significant. TV have shown the lowest amount of NH\u003csub\u003e4\u003c/sub\u003e-N in runoff water and NO\u003csub\u003e3\u003c/sub\u003e-N, its behavior was similar to that of the NH\u003csub\u003e4\u003c/sub\u003e-N. The next lowest amount of NH\u003csub\u003e4\u003c/sub\u003e-N and NO\u003csub\u003e3\u003c/sub\u003e-N in runoff water showed in TW. Soil conservation methods have significantly reduced the removal of AN compared to the TO. The amount of NH\u003csub\u003e4\u003c/sub\u003e-N and NO\u003csub\u003e3\u003c/sub\u003e-N removal in TV was 1.3 and 0.8 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003eAvailable Phosphorus\u003c/h2\u003e \u003cp\u003eAvailable phosphorus (AP) is an essential nutrient for tea cultivation, and phosphate fertilizers are commonly applied to meet crop nutrient requirements and to increase tea production. However, phosphorus loss through surface runoff can contribute to aquatic eutrophication, posing a serious threat to environmental safety. Available Phosphorus (AP) changes in SCM are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The results show that there was no significant difference in the rate and amount of AP removal through surface runoff between SCMs and TO treatments. The AP removal rate was in the range of 0.88 mg/l \u0026ndash; 1.26 mg/l. Considering of amount of AP removal was in range from 0.42 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 2.1 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The lowest AP showed in TV (0.42 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) followed by TW (0.51 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). According to the research done by other countries, only a fraction of applied phosphorus for tea is typically taken up by tea plants, with large proportions retained in soil or lost in runoff and erosion. One study in Taiwan found that less than 5% of applied phosphorus was exported in storm runoff, while the majority persisted in the soil pool, indicating that improving fertilizer use efficiency is key to reducing environmental loss (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Similarly, the results of this study showed that AP losses were not significantly different among treatments. And AP loss is 1.1\u0026ndash;2.7% of applied phosphorus (35 kg/ha/yr) under the SCM treatments and 6.7% under the TO. The most applied phosphorus was either retained in the soil or taken up by tea plants, which is consistent with previous findings that phosphorus in tea-growing soils is strongly adsorbed by soil minerals and organic matter.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003eAvailable Potassium (K)\u003c/h2\u003e \u003cp\u003ePotassium (K) is a major nutrient in tea but K losses in runoff have been given less attention than N and P, not only tea land but also in most crop due to K is considered as less or not threat element to water and environmental quality. The available potassium (AK) is that readily uptake to the plant. The concentration (rate) and amount in runoff water are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. It has been shown that there is no significant difference in potassium concentration between TO and the SCM\u0026rsquo;s and also among the SCM\u0026rsquo;s. When calculating amount of potassium per hectare, the amount varied between 1.27 and 9.5 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. However, the removal of potassium from the SCMs with runoff water was significantly lower compared to the TO. The lowest amount (1.27 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) of potassium removal was observed in TV soil conservation treatment. The significantly better conservation of the soil nutrients showed vetiver planted on bund resulting in the soil fertility build-up in crop land in India (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In the research on several cropping system, the K loss with runoff was 0.5 kg K ha\u0026thinsp;\u0026minus;\u0026thinsp;1 in crop planted along the contour and planted in along the slope was 3.2 kg K ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Leite, 2018). Tea planting is also done in the contour as agronomic soil conservation method and convenient for cultural practices. This is also positively support to reduce surface runoff and nutrient loss.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe results of the study demonstrate that nutrient removal from tea land is closely proportional to the volume of runoff water discharged. Established soil conservation measures have significantly reduced the removal of available nitrogen compared to tea only treatment.\u003c/p\u003e \u003cp\u003eAmong the SCMs, terrace with vetiver grass showed the lowest AN losses with NH₄⁺-N and NO₃⁻-N removal 1.3 and 0.8 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Rate of available phosphorus and available potassium removal was more or less similar across all treatments and available phosphorus loss by runoff was 0.42 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e yr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in terrace with vetiver grass. Similarly, the lowest amount of available potassium removal was observed in terrace with vetiver grass (1.27 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) soil conservation measures. TV was identified the most effective nutrient saving measure, due to reducing AN, AP and AK losses by 6.9 (78%), 1.62 (80%) and 7.8 (86%) kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eyr\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003erespectively compare to tea only. Combination of SCM has been applied to conserve soil and moisture in tea land, where terrace is physical/ mechanical measure to reduce flow rate of runoff and strips of vetiver grass provide biological barriers to retain small soil particle flow through runoff water. In conclusion, combination of physical and biological soil conservation measures is highly effective for nutrient saving that removal through surface runoff. Among the treatment in this study TV the most effective SCM and followed by terrace wall for steep tea lands.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eL.A.S.P. Jayasinghe conducted the research, carried out data collection, performed data analysis, and wrote the main manuscript. Simplicio M. Medina supervised the project and its implementation and critically reviewed and revised the manuscript. Both authors read and approved the final version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAmarasekara, M G T S., Dayawansa, N D K and De Silva, R P. Soil erosion and nutrient transport from lands under intensive agriculture in upper Mahaweli catchment area in Sri Lanka. World Science echo. 2018: 1(1)\u003c/li\u003e\n\u003cli\u003eAnon,. Fertilizer Recommendations for Immature Tea. Circular No: SP 03. Tea Research Institute of Sri Lanka, 2000. \u003c/li\u003e\n\u003cli\u003eBlanco, H. and R. Lal. Principals of soil conservation and management. Springer, Dordrecht. 2008.\u003c/li\u003e\n\u003cli\u003eBorin M, M. Vianello, F. Morari and G. Zanin. 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Runoff capture through vegetative barriers and planting methodologies to reduce erosion, and improve soil moisture, fertility and crop productivity in southern Orissa, India. Nutr Cycl Agroecosyst. 2011: 89;45\u0026ndash;57\u003c/li\u003e\n\u003cli\u003eDouglas, C. L., King, K. A and Zuzel, J. F. Nitrogen and phosphorus in surface runoff and sediment from a wheat-pea rotation in northeastern Oregon. Journal of Environmental Quality. 1998: 27; 1170\u0026ndash;1177\u003c/li\u003e\n\u003cli\u003eHansen, N. E., Vietor, D. M., Munster, C. L., White, R. H. and Provin, T. L. Runoff and nutrient losses from constructed soils amended with compost. Applied and environmental soil science. 2012\u003c/li\u003e\n\u003cli\u003eHudson, N. W. Field measurement of soil erosion and runoff. Food and agriculture organization of united nation, Rome. 1993\u003c/li\u003e\n\u003cli\u003eJayasinghe, L. A. S. P., Hettiarachchi, L. S. K., Medina, S. M. and Ekanayake, E. M. G. P. B. Quantification of soil loss under different soil conservation practices of mid country tea lands in Sri Lanka. National Symposium on tea 2023. Tea Research Institute of Sri Lanka. 7\u003csup\u003eth\u003c/sup\u003e December 2023, Grand Monrch, Thalawathugoda. 2023.\u003c/li\u003e\n\u003cli\u003eLeite, M. H. S., Couto, E. G., Amorim, R. S. S., \u0026amp; Scaramuzza, J. F. Loss of water and nutrients in different soil tillage systems subjected to natural rainfall in the state of Mato Grosso, Brazil. Engenharia Agr\u0026iacute;cola. 2018: 38; 864\u0026ndash;873. https://doi.org/10.1590/1809-4430-Eng.Agric.v38n6p864-873/2018\u003c/li\u003e\n\u003cli\u003eNakasone, H. and Yammamoto T. How much does diffuse pollution affect an aquatic ecosystem? \u003cem\u003eProc. of Diffuse Pollution Conference Dublin. \u003c/em\u003e2003; 125-129.\u003c/li\u003e\n\u003cli\u003eNi, K. Liao, W.Y., Yi, X.Y., Niu, S.Y., Ma, L.F., Shi, Y.Z., Zhang, Q.F., Liu, M.Y. and Ruan, J.Y. Fertilization status and reduction potential in tea gardens of China. J. Plant Nutr. Fertil. 2019: 25; 421\u0026ndash;432.\u003c/li\u003e\n\u003cli\u003eNissanka, S. P., Punyawardena, B. V. R., Premalal, K. H. M. S., and Thattil, R.O. Recent trends in annual and growing seasons rainfall of Sri Lanka. International Conference on the Impact of Climate Change on Agriculture. Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, Sri Lanka. 2011.\u003c/li\u003e\n\u003cli\u003eOwuor, P. O. Effects of Fertilizers on Tea Yields and Quality: A Review with Special Reference to Africa and Sri Lanka. International Journal of Tea Science. 2001: 1(1). \u003c/li\u003e\n\u003cli\u003eOwuor, P. O. and Othieno, C. O. Optimizing nitrogen fertilizer application rates to different tea cultivars. Trops. Sci.. 1996: 36; 211 \u0026ndash; 223\u003c/li\u003e\n\u003cli\u003ePunyawardena, B. V. R., Bandara, T. M. J., Munasinghe, M. A. K. and Bandara, N. J. Agro-ecological regions of Sri Lanka. Natural Research Management Centre, Department of Agriculture. 2003.\u003c/li\u003e\n\u003cli\u003eSchuman, G. E., Burwell, R. E., Piest, R. F. and Spomer, R. G. Nitrogen losses in surface runoff from agricultural watersheds on Missouri valley Loess. Journal of environmental quality. 1973: 2(2) ;299-302\u003c/li\u003e\n\u003cli\u003eSenerathne, M. M. P. Soil and water conservation; field book. Department of Agriculture. Peradeniya. Sri Lanka. 2014. \u003c/li\u003e\n\u003cli\u003eSoil fertility. FAO. https://www.fao.org/global-soil-partnership/areas-of-work/soil-fertility/en\u003c/li\u003e\n\u003cli\u003eToy, T. J., Foster, G. R. and Renard, K. G. Soil erosion, processes, prediction, measurement, and control. John Wiley \u0026amp; Sons, New York. 2002; 25-43.\u003c/li\u003e\n\u003cli\u003eYamada, T., Inoue, T., Tsushima, K., Nagai, M. and Kiso, Yoshiaki, K. Nutrient Loss from a Tea Plantation Area in Japan. Journal of Water and Environment Technology. 2009; 7 (4).\u003c/li\u003e\n\u003cli\u003eGoulding, K., Murrell, T. S., Mikkelsen, R., Rosolem, C., Johnston, J., Huoyan Wang and Alfaro, M. Outputs: Potassium Losses from Agricultural Systems. \u003cem\u003eIn:\u003c/em\u003e Improving Potassium Recommendations for Agricultural Crops. 2020\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"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":"discover-soil","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Soil](https://link.springer.com/journal/44378)","snPcode":"44378","submissionUrl":"https://submission.nature.com/new-submission/44378/3","title":"Discover Soil","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Climate change, Nutrient loss, soil conservation, soil erosion, steep agriculture","lastPublishedDoi":"10.21203/rs.3.rs-8498265/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8498265/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSoil nutrient loss occurs naturally through soil erosion, runoff, leaching and burning of crop residues, but this process has accelerated due to improper land and crop management. Minimizing of nutrient loss is crucial under the climate change, especially in steep agricultural lands. This study was conducted to evaluate the effectiveness of soil conservation measures in reducing nutrient loss in a mature tea field at Kenilworth Estate, Ginigathhena, Sri Lanka (6\u0026deg;59' N, 80\u0026deg;29' E), located at mid-elevation. The slope of the study area was 60\u0026ndash;72%. Erosion plots were arranged in Randomized Complete Block Design with four treatments; stone terrace (T), stone terrace with Vetiver grass (TV), terrace wall (TW) as soil conservation measures (SCM), and tea without conservation (TO) as control. Runoff were collected to the sediment tanks attached to the plots to analyze nutrients; Available Nitrogen (AN), Available Phosphorous (AP) and Available Potassium (AK) from October 2020 to November 2021 with 5970 mm rainfall. The NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e-N concentration in runoff was not significant in different SCMs and NH\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e-N concentration in runoff was significantly low in TV. The NH\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e-N and NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e-N removal in TV was 1.3 and 0.8 kg ha\u003csup\u003e-1\u003c/sup\u003e yr\u003csup\u003e-1\u003c/sup\u003e respectively. The amount of AP removed by runoff was significantly higher in TO (2.1 kg ha\u003csup\u003e-1\u003c/sup\u003e yr\u003csup\u003e-1\u003c/sup\u003e) and 0.9,0.5,0.4 kg ha\u003csup\u003e-1\u003c/sup\u003e yr\u003csup\u003e-1\u003c/sup\u003e in T, TV, TW respectively. AK loss through runoff was not significant among treatment and lower in SCMs. TV was the most effective nutrient saving measure, reducing AN, AP and AK losses by 6.9 (78%), 1.7 (80%) and 7.8 (86%) kg ha\u003csup\u003e-1\u003c/sup\u003eyr\u003csup\u003e-1\u003c/sup\u003erespectively due to combination of physical and biological measures.\u003c/p\u003e","manuscriptTitle":"Nutrient Losses Through Surface Runoff in Different Soil Conservation Practices in Mid Elvation Tea Lands in Sri Lanka: Implications for Climate Change Adaptation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-07 08:57:46","doi":"10.21203/rs.3.rs-8498265/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-19T12:55:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-13T12:03:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-13T12:02:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Soil","date":"2026-01-02T05:23:09+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-soil","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Soil](https://link.springer.com/journal/44378)","snPcode":"44378","submissionUrl":"https://submission.nature.com/new-submission/44378/3","title":"Discover Soil","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"81524641-15ae-4f26-bf2e-c80180ba9d06","owner":[],"postedDate":"January 7th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T11:39:05+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-07 08:57:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8498265","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8498265","identity":"rs-8498265","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}