A comparative study of Chilli (Capsicum Annuum) on biomass production by phosphorus application through micro-dose placement, broadcast, and optimized seedling Root-dip in P-enriched slurry

A sustainable method of phosphorus (P) fertilizer application is needed to support crop production, due to the limited P reserves and negative environmental impact caused by excessive P application in agriculture. This study proposes a comparison of P management that enhance P nutrition of Chilli seedlings (variety: Arka Khyati ) through seedling root-dipping (SRD) into P-enriched slurry (SSP-amended soil slurry; pH of 8.1), micro-dose placement (MDP; drill and place closer to plant root), and full dose placement by broadcasting (FD). In SRD method, seedlings were dipped in three different P concentrations (0, 50, and 100 mg P 2 O 5 kg -1 ) for varying durations (0, ½, 1, 2, 3, and 4 hours) and then transplanted into pots, along with the MDP and FD treatments, resulting in 15 total treatments with 5 replications. The amount of P adhered to the seedling roots in the SRD treatments was 21 and 90 times lower than that P applied in MDP and FD treatments, respectively. The best performance in biomass production was observed in seedlings dipped in 100 mg P 2 O 5 kg -1 for 2 hours in SRD, (dipping in higher concentrations with longer durations resulting in plant death). Overall, the comparison showed a 52%, 178%, and 293% increase in biomass production compared to the control for FD, MDP, and SRD, respectively. P-use and -recovery efficiency followed the same trend. Further multilocational trials are necessary to assess this method, and it is recommended to apply a reduced amount of P to maintain a balanced of native P in the soil.