Productivity, nutrient uptake and nitrogen economy of wheat (Triticum aestivum) in a conservation agriculture-based cotton (Gossypium herbaceum)–wheat system

Conservation agriculture (CA) practices like zero-till and residue retention along with nitrogen management is vital for improving degraded soil health and optimizing the yield potential of wheat (Triticum aestivum L.) crop. Present study was carried out during winter (rabi) seasons of 2021–22 and 2022–23 at ICAR-Indian Agricultural Research Institute, New Delhi for optimizing wheat productivity in a conservation agriculture-based cotton (Gossypium herbaceum L.)-wheat system. The experiment was laid out in a randomized complete block design (RCBD) with three replications consisting of combination of 3 different crop establishment methods, viz. permanent broad bed (PBB), permanent narrow bed (PNB) and zero-till flatbed (ZTFB) with residue (R) and without residue along with 2 doses of nitrogen (75N, 100N) and conventional tillage (CT). The CA-based practices showed overall superior response in terms of growth, yield and nutrients uptake of wheat than CT. Among them, the PBBR100N resulted in significantly higher plant height, leaf area index, dry-matter accumulation, crop growth rate, and relative growth rate compared to PNB, PBB, ZTFB and CT. This treatment led to significantly higher grain (16.2–19.4%) and straw (9.6–11.6%) yields than CT. The net returns and benefit cost ratio (23.4% and 27.9%) were also higher than that in CT. Again, in this treatment, N uptake by wheat crop was higher by 85%, P uptake by 53.1%, and K uptake by 40.1%, and available soil N, P and K by 16.1, 25.3 and 43.7%, respectively than CT. Therefore, the study suggests that the adoption of CA-based practices with broad bed in Indo-Gangetic Plains will not only enhance the productivity of wheat but also result in improved soil health by restoring soil fertility.