Long-term impact of conventional and zero tillage on wheat (Triticum aestivum) in red and lateritic zone of West Bengal

Farmers’ participatory trials were conducted for 7 years during winter (rabi) seasons of 2004–05 to 2010–11, in red and lateritic zone of West Bengal, India, to evaluate the long-term effect of conventional (CT) and zero (ZT) tillage on yield and yield attributes, nutrient uptake, nutrient-use efficiency, economics of wheat [Triticum aestivum (L.) Emend. Fiori & Paol.]. The most influential climatic factor, best planting date for different cultivars and best cultivar corresponding to different tillage practices were also adjudged in this study. Zero tillage increased wheat yield on an average by 20.7%, net returns by 9, 523/ha, N, P and K uptake by 16, 19.1 and 14.0% respectively, over CT. The most important contributing character to the total variability of wheat grain yield was number of spikes/m², which contributed 11.7 and 25.8% variation to the ZT and CT yield, respectively. Multiple regression coefficient analysis revealed that the influential climatic factor for ZT and CT wheat was minimum temperature and relative humidity, respectively. While evaluating performance of wheat cultivars under 2 tillage practices on different planting dates, ‘PBW 343’ and ‘HD 2733’ gave the maximum yield between 8 and 15 November, ‘K 9107’ and ‘Swarna (L)’ between 1 and 7 November with ZT method. In contrast, all the cultivars gave the maximum yield in CT within the first week of November, except ‘PBW 343’. Interaction between tillage practice and wheat cultivar revealed that ‘K 9107’ and ‘PBW 343’ were most stable cultivar for this zone across tillage options. The lowest yield loss attributable to delay in planting was obtained in the cultivar ‘Swarna (L)’ (7.85 kg/ha/day) and ‘K 9107’ (7.21 kg/ha/day) for ZT and CT respectively, indicating higher stability of theses cultivars for late-sown condition in this region.