Direct and Residual Effect of Green Manuring in Relation to Fertilizer Nitrogen on Toria (Brassica napus L.) and Sunflower (Helianthus annuus L.)

Field experiment was conducted to study the direct and residual effect of green manuring on torio (Brassica napus L.) and sunflower (Helianthus annuus L.), respectively. Nitrogen was applied @ 0, 20, 40, 60, 80 and 120 kg ha⁻¹ with and without green manuring. Green manuring alone (without any fertilizer nitrogen) manifested in a mean yield increase of torio by 122 percent equivalent to solitary application of 60 kg N ha⁻¹. Residual effect of green manuring on the following sunflower crop resulted in an average 317 kg ha⁻¹ higher yield compared to the treatments without any residual green manure. However, the mean response to residual green manure alone was restricted to 50 per cent. Nitrogen-use efficiency varied with N level and the direct or residual effect of green manuring. Value: cost ratio indicated that green manuring with fertilizer N up to 60 kg ha⁻¹ resulted in higher economic return. Fallow period after harvesting of sunflower can be utilized productively by sowing cowpea and its incorporation into the soil for green manuring, in this rotation.