Determination of planting date for annual feed legumes as cover crop in fallow and their effects on soil physical properties and wheat yield in the dryland condition.ý

In order to determination most suitable planting date three annual feed legumes as a cover crop in fallow and their effects on some soil physical properties and wheat yield in dryland condition this research was carried This research carried out in two separate phases and three independent experiments for 5 years (2006-2011) in two location research station ( Khodabanda and maraghe). The experiment was performed as a split plot based on Randomized Complete Block Design with four replications and included ten treatment.In this experiment planting dates (autumnal, dormant and vernal ( spring ) seeding ) as a main plot and species forage crops as a sub plot take into considerate. The applied forage crops belonged to the three species of forage plants namely grass pea (Lathyrus sativus L.), Hungarian vetch (Vicia panonica L.) and field pea (Pisum avestum L.). In this study the check treatment was taking into considerate (without seeding cover crop). In dry matter yield data's combined analysis results, the effect of planting dates, species of forage plants and interaction between of planting dateý Ã species of forage plant was not significant .highest dry matter yield grass pea ( 0.69 t ha-1), field pea (0.47 t ha-1) was obtained from dormant seeding and Hungarian vetch ( 0.46 t ha-1 ) from autumnall seeding. Spring seeding in each three legume allocated lowest dry matter yield. Among forage crops species in terms of average nitrogen yield deference was significant at 1% level probability. Highest nitrogen yield was obtained from grass pea (14.9 kg ha-1). The effect of forage crops planting date on wheat grain yield was not significant. In adding green manure of grass pea treatment grain wheat was 160, 190 and 180 and kg ha-1 higher than Hungarian vetch, field pea and control treatments so that, this difference was significant at 5% level probability. In both phases the effect of planting dates on Mean Weight Diameter. Potassium and organic carbon of soil was not significant. Between potassium (386 ppm) an organic carbon (0/67 percent) values soil in control treatment compare with adding green manure of each three forage crops deference was significant at 5% level probability. In both phases highest and lowest potassium and organic carbon were obtained from adding green manure grass pea ant control treatments respectively. Aggregating the results implied that for improvement soil physical properties and access high dry matter forage crops yield, autumnal seeding Hungarian vetch and dormant seeding grass pea and field pea prefer for other seeding dates.