Nutrient use efficiency indices of N, P, and K under rice-wheat cropping system in LTFE after 34th crop cycle

Nutrient efficiency concept is used to increase the overall performance of cropping system by providing economically optimum nutrition to the crop and at same time minimizing nutrient losses from the crop yield. The study was undertaken on the AICRP-IFS experiment located at BAU, Sabour having twelve treatments replicated four times in randomized block design. The data were taken after 34th cropping cycle. In this study, a modest initiative has been undertaken to assess the various nutrient use efficiencies for N, P, and K in rice-wheat under different integrated nutrient management (INM) treatments involving substitution of N by farm yard manure, wheat straw, and green manure along with levels of recommended doses of fertilizers and farmers' practice. The results revealed that the overall AE, PE, APE, PFP, IUE, ARE, and partial nutrient balance (PNB) of N, P, and K for wheat crop was comparatively lower than that of rice crop which reflects that the residual effect of applied organic manures and fertilizers was more than the direct effect. PNB of crops for both the crops was near to 1 in INM plots which indicates that the yields and fertility status of soil is being sustained with respect N and P. However, K mining is being indicated through higher values of PNB for K. Overall, the results indicated that the integrated use of organic manures and inorganic fertilizers for last 34 years likely improved soil fertility, increased sustainable crop yield and uptake thereby led to increased nutrient use efficiency of applied nutrients and crops.