Effect of green manuring in combination with nitrogen on soil fertility and yield of bread wheat (Triticum aestivum) under double cropping system of Sinana-dinsho, Southeast Ethiopia

An experiment was conducted at Sinana-Dinsho from 2001 to 2003 to evaluate the short term effects of substituting vetch green manuring for fallow in 'Ganna' season under double cropping system. Three land preparation treatments (weedy fallow, Vetch harvested and Vetch under ploughed) were used in the main plots with three nitrogen rates (0, 20.5 and 41 kg N/ha) in the subplot. After three weeks of green manuring, a slight decrease in pH and available phosphorus and an increase in organic carbon content was observed. Green manuring vetch and fallow treatments gave comparable plant height, grain yield and straw yield. But, when vetch biomass was harvested and removed at flowering stage, yield of bread wheat was reduced. However, the total farm productivity could be higher when livestock production was considered. Hence, growing forage legumes is preferable to fallowing the land.