Effect of Conventional and Water-Soluble Fertilizers on Phosphorus Fractions and their Relationship with Soil Properties in Ratoon Sugarcane

Abstract

Purpose: To investigate the impact of water-soluble fertilizers on phosphorus dynamics in drip-irrigated ratoon sugarcane. Methods: The experiment was conducted at Zonal Agricultural Research Station, V.C. Farm, Mandya during 2020-21. The soil was described as red sandy loam with neutral pH, normal electrical conductivity, medium organic carbon, low available nitrogen and medium phosphorus and potassium content. A Randomized Complete Block Design with three replications was employed. The study involved seven treatments using the VCF-0517 sugarcane variety. Different fertilization methods were used, including the basal application of Single Super Phosphate (SSP) with or without Farm Yard Manure (FYM), as well as the application of water-soluble fertilizers (WSF). Results: The results indicated that treatments involving the basal application of SSP with FYM and without FYM led to significantly higher levels of various phosphorus forms (saloid-P, Al-P, Fe-P, RS-P, Occluded-P, and Ca-P) compared to those treated with water-soluble fertilizers. At the grand growth phase (180 days after ratoon), available phosphorus displayed strong positive correlations with various phosphorus forms, suggesting that the application of phosphorus increased its availability to the crop while also enhancing fixation. Available phosphorus showed significant positive associations with electrical conductivity (EC), organic carbon (OC), available potassium and a weaker positive relationship with available nitrogen. Conclusions: Basal SSP application, with or without FYM, boosted phosphorus levels over water-soluble fertilizers. Positive correlations between available phosphorus and various forms suggest increased crop availability and fixation. Soil properties (EC, OC, available potassium, pH) impacted phosphorus availability for sugarcane.