**4.1 Zero tilled wheat**

Zero tillage is an already proven resource conserving technology for wheat crop and it was found that it results in increase in crop yield by 5–7% (140–200 kg ha−1) and food production by 0.7% (343000 tonnes ha−1) in the Indo Gangetic plains [46]. Seed and fertilizers are placed by opening the furrows with the help of equipments like zero till ferti seed drill or Happy seeder in a single go in standing crop residues by completely avoiding the primary tillage operations. Singh *et al.* [47] reported that the grain and straw yield obtained by sowing of wheat by happy seeder is higher than the farmers practice in one of the two experimental locations (**Table 3**). This method reduces the tillage operations with a single pass and saves fuel, labour, farm machinery cost, water, fertilizers etc. [48], permits earlier wheat planting in rice-wheat system and control the problem of *Phalaris minor* [46]. Pandey *et al*. [49] reported higher grain yield (3440 kg/ha) and B:C ratio (2.38) for zero tilled wheat as compared to conventionally grown wheat with a grain yield of 3224 kg/ha and B:C ratio of 1.81 in Kailali district of Nepal. Since residue retention is a common practice in zero tillage system, so the organic matter content of the soil is also increased and soil compaction is reduced due to enhancement of biological activities in soil. The constrains of adapting zero tillage in wheat under RW system of developing countries are the small size of land holdings of small and marginal farmers and the involvement of lumpy technology (i.e. non-divisible piece of machinery) [5, 6] involving high procurement cost.
