Spring wheat response to nitrogen, tillage and cropping system under rainfed condition

The objective of this research work was to assess the existing summer fallow elimination by growing short duration leguminous crop (mungbean) and reduction in number of plows could be a good substitute in recent shift of rainfall pattern. The traditional tillage frequencies (exceeding 4–5 plow + 2 harrows) of the summer fallow land without the addition of commercial fertilizers to wheat are the century-old practices in the project area. The rainfall efficiency is very low and is certainly related to the low and marginal fertility status. The existing wheat–fallow–wheat (W–F–W) where field remains without crop for five–six months in summer was compared with the proposed wheat–mungbean–wheat (W–Mb–W) cropping system by eliminating the summer fallow. Four tillage systems, i.e. no tillage (NT), conventional tillage (CT), reduced tillage (RT), and maximum tillage (MT), were employed before wheat sowing. Wheat (Triticum aestivum L., cv. Tatara) was sown at the residual moisture of the monsoon rainfall and four levels of N (0, 25, 50, and 75 kg ha⁻¹) were added at the time of wheat sowing. Results show that the wetter year (second year) of the experiment had higher soil water (26.35%), grain yield (2,561 kg ha⁻¹), harvest index (43.5%), and water use efficiency (WUE) (6.1 kg ha⁻¹ mm⁻¹). The existing W–F–W cropping system had more soil water (17%), grain yield (17%), harvest index (1%), WUE (9%), and grain N (23%) than W–Mb–W. CT system had more soil water (13%), grain yield (5%), WUE (2%), harvest index (3%), and grain N (5%) as compared with NT. CT also had more soil water contents (5%), grain yield (3%), WUE (10%),), and harvest index (3%) than MT. Nitrogen application had increased grain yield (33%), WUE (25%), harvest Index (3%), and grain N (7%) compared with the control (no N application). The present study does not suggest the replacement of summer fallow with mungbean crop as for as the grain yield and WUE is concerned. Apparently no negative impact of CT was recorded on grain yield and other parameters; however, to be on the safe side, RT with application of 75 kg N ha⁻¹ is recommended for areas with similar rainfall pattern and soil fertility status.