Introduction of two local races of grass pea (Lathyrus sativus L.) and common vetch (Vicia sativa L.) as cover crops for cold and cold temperate regions of the Iran

Due to climate limitations in most of the cold and cold temperate provinces of the country ,irrigated fields of wheat and barley after harvest ( around June ) are ploughed and left with no cover till spring when are devoted to planting of potato, bean, onion and sunflower. Grass pea and common vetch being short vegetative period, are drought and cold tolerate plants which could be planted as second crop after cereals and rapeseed harvest and used their forage at 50% flowering stage(around mid Oct.) as direct graze, green / dry fodder or as green manure for soil fertility .This study was carried out as on farm research project for evaluation of the finding of the completed research of Zanjan Agricultural and Natural Resources Research Center at 28 locations over 11 provinces of the country. Grass pea and common vetch were planted after rapeseed and cereals harvest each on o.5 ha-1 at 250 grain / m2. Land preparing and other cultural practices were conducted following locals / farmers patterns; and to compare the amount of green/ dry fodder yield of each plant, 6 plots of ten m2 were selected randomly and weighed separately .Data of the experimental fields were exposed to T test analysis and combined analysis were conducted for over all the results. Results indicated that significant differences were present among the locations and between the two cover crops. Yield of green forage, crude protein and Nitrogen production in grass pea was higher than common vetch. Range of variations of green forage in grass pea and common vetch showed between 12.33-43.66 and 7.5- 49.83 ton/ha-1 respectively; average of total dry matter in grass pea was 5.3 ton/ha-1 but it was estimated 5.5 ton/ha-1 in common vetch. Interaction of cultivars × environmental conditions indicated significant differences at 1% probability. The highest and lowest amounts of dry forage were recorded in Ijroud of Zanjan province (11.73 ton/ha-1) and Aahar of East Azarbaijan with 1.76 ton/ha-1. studying the amount of nitrogen, phosphor, potasium and four micro nutrients of zinc, cooper, magnesium and iron as indexes of green manure production, the ability of grass pea and common vetch in fixation of the these minerals were estimated per one ton of dry matter as 39.3 kg N, 2.78 kg P,31.3 kg K, 10.8 g Cu, 61.3 g Zn, 64 g Mn, 243.2 g Fe and 34.9 kg N, 2.82 kg P, 28.3 kg K, 9.3 g Cu, 39.1 g Zn, 60 g Mn, and 243,2 g Fe respectively. The total average production of N, P, and K in grass pea and common vetch fields were recorded as 81.46, 14.209,166. 83 and 191.9, 15.5 and 155 6 kg/ ha-1 respectively. The over all results showed that these crops could be planted as 2nd crop in summer fallow situations leading to provide parts of forage requirement, cultural management of summer weeds and losses recycling of wheat, barley and colza due to grain falling. In the case of planting these crops as green manuring, most or the entire nitrogen requirement of next crop will be supplied, fertility of the soil could be improved and sustainable production of other winter / summer crops might be assured.