System-based management of phosphorus in a non-flooded rice-lentil system on alkaline soil

The study aimed to design efficient and sustainable phosphorus (P) management modules for non-flooded rice [system of rice intensification (SRI)]-lentil systems on an alkaline Fluvisol . For this, seven variable P management treatments i.e., one P control (P [0–0] ) [subscript value represents kg P ha −1 to non-flooded rice followed by lentil], three sole fertilizer-P treatments with variable rates to component crops (P [22–22] , P [33–11] , P [11–33] ), three integrated treatments ([P 11–11 + phosphate solubilizing bacteria (B)], [P 16.5–5.5 + rice residue recycling (RR) + B], [P 5.5–16.5 + lentil residue recycling (LR) + B]) along with recommended sole fertilizer-P rate to flooded rice-lentil system (P [22–22]FR ) as conventional practice were evaluated for soil–plant P relations, crop yield, nutrient use efficiency and budgeting. The rice residue recycling integrated treatment (P [16.5–5.5] + RR + B) increased P availability in both rice (5–6%) and lentil (9–10%) seasons, subsequently resulting in increased agronomic P use efficiency (175–183%) and system productivity (7%) over the recommended sole fertilizer-P treatment P [22–22] ( p < 0.05). The system-based sole fertilizer-P treatments (P [22–22] , P [33–11] , P [11–33] ) did not differ in system productivity; however, a higher rate of fertilizer-P for rice (33 kg P ha −1 ) increased its yield. Both crop residue recycling integrated treatments resulted in a marginal negative P balance (− 2.5 to − 1.6 kg P ha −1 y −1 ), while the sole fertilizer-P treatments led to a higher positive P balance (> + 14 kg P ha −1 y −1 ). Hence, system-based rice residue recycling integrated P management could be an improved P management option for non-flooded rice-lentil systems on alkaline soils given that a positive P balance is maintained.