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Fertigation in rice-based cropping systems is catching up the attention of farmers for producing high yield of crops and improved fertilizer use efficiency. As fertigation with different combinations of irrigation and nitrogen (N) levels can interact with depth of rooting system of different crops as well as soil tillage, this study was carried out in 2017 in the fourth year of on an on-going long-term experiment initiated in the summer (Kharif) season of 2014 to understand the effect of fertigation on soil organic carbon pools and yield in zero-till direct-seeded rice-based cropping systems. The experiment was laid out in a split plot design with three levels of fertigation as main plots: N @ 20 kg ha−1 in rice through fertigation followed by 200 mm irrigation in post rice crops (W1), N @ 40 kg ha−1, in rice through fertigation followed by 300 mm irrigation in post rice crops (W2), N @ 60 kg ha−1, in rice through fertigation followed by 400 mm irrigation in post rice crops (W3). The sub-plot treatments consisted of zero till direct seeded durum wheat, barley, chickpea, linseed, lentil and lathyrus crops after rice. The rice crop was also under zero till direct seeded cultivation system. The highest grain yield of rice was observed in the rice-lathyrus cropping system with treatment W3 where N was applied in three equal splits, first being basal application and the two subsequent applications through surface inline drip irrigation. Both in surface and sub-surface soil layers, soil carbon stock, carbon pools and aggregate associated carbon were found to be more in the legume based cropping systems and with W3 fertigation regime than in other cereal based cropping systems. The grain yield was found negatively and highly significantly correlated with less labile pool (r=-0.63**) whereas very labile pool was positively significantly correlated with labile (r = 0.89**), less labile (r = 0.53**) and non-labile (r = 0.91**) pools of carbon. Overall, fertigation levels influenced the crop yield and soil organic matter in zero-till direct-seeded rice-based cropping systems. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]