Boosting the Soil Phosphorus Availability to Plants by Using Silicon-Rich Crop Residues and Reducing Fertilizer Requirements

Purpose Crop residues rich in silicon (Si) viz. rice straw (RS), sugarcane leaf (SL) etc., are agricultural waste generated abundantly in India and elsewhere, have great potential for alleviation of phosphorus (P) deficiency in soil. Quantitative research on Si-rich crop residue's impact on P availability in Indian soils is limited. Methods This investigation assessed P release influenced by Si-rich crop residues in two different soils, viz. alkaline alluvial soil collected from New Delhi (Olsen-P 6.2 mg kg −1 ) and calcareous alluvial soil collected from Samastipur (Olsen-P 6.8 mg kg −1 ) in laboratory experiment. Further, in a greenhouse experiment, impacts of applied Si on P availability to wheat crop (cv.- HD 2967) in alkaline alluvial soil of New Delhi was assessed. Results Results of the P release study reveals that application of Si through various sources significantly enhanced 0.01 M CaCl 2 extractable P in both soils. In the greenhouse experiment, crop residues significantly and positively impacted soil available P and growth parameters of wheat like straw yield, grain yield, straw P uptake and grain P uptake. Combined application of a reduced recommended dose of P (RDP) with RS or SL could produce statistically similar wheat yield to that of 100% RDP alone. Conclusion Applying these residues could potentially reduce P fertilizer rates by 25–50% without compromising wheat yield, resulting in substantial P fertilizer savings. Graphical Abstract