Partial Substitution of Chemical Fertilizers with Organic Supplements Increased Wheat Productivity and Profitability under Limited and Assured Irrigation Regimes

Crop wastes could be applied in conjunction with synthetic fertilizers to satisfy crop nutritional needs and enhance soil fertility. A field experiment was carried out during winter 2019–2020 at the AMK Research Farm (Palatoo) Mardan, KPK (Pakistan) to investigate the combined effect of phosphorous (PS) and organic sources (OSs) on wheat productivity under different irrigation regimes. The experimental factors were: two irrigation regimes (limited and full irrigation), three inorganic sources of phosphorus (triple super phosphate (TSP), single super phosphate (SSP) and di-ammonium phosphate (DAP)) applied at 90 kg ha−1, and three organic amendments (farmyard manure (FYM), mung bean residue (MBR), and canola residue (CR)) applied at a rate of 10 t ha−1. A control plot (no phosphorus or organic supply) was included. A randomized complete block design (RCBD) with three replications was adopted. Among the fertilization strategies, SSP + FYM outperformed all other P fertilizers combined with legume or nonlegume residues in terms of grains per spike−1 (52), thousand-grain weight (41.6 g), biological yield (9.7 t ha−1), and grain yield (4 t ha−1). Under full irrigation, improved yield, yield components, and profits were obtained compared to the limited irrigation regime. Three clusters were obtained after applying an Agglomerative Hierarchical Clustering (AHC), and Principal Component Analysis (PCA) conferred the positive effects of inorganic P with FYM on the wheat yield and its related parameters. This study indicated that the productivity of wheat under the SSP + FYM fertilization strategy was found to be more economical with respect to the benefit–cost ratio (BCR). The combined application of SSP + FYM was more profitable in terms of a higher BCR (3.25) than other treatments under the full irrigation regime.