The effect of soil moisture level on development of perennial leguminous grasses in conditions of the Kirov region, Russia, is considered. The results of previous field trials revealed that the soil moisture content was higher under winter rye compared with spring crops or the absence of crops. Growing of a vetch-oat mixture for green fodder resulted in the driest soil conditions compared with oat, barley and wheat. Advantages of growing birdsfoot trefoil under the cover of cereal crops are discussed as a way of weed control, also resulting in better soil water conditions. However, birdsfoot trefoil had more light and soil moisture content and showed more intensive above-ground growth in the absence of a crop cover. Field trials were conducted to study the complex relationship between the growth and yield of spring and winter crops, availability of water and light, and weed control and production of high yield of green fodder. Data are tabulated on development and green fodder yield of birdsfoot trefoil during the 1st and 2nd years of growth without plant cover compared with growth under the cover of winter rye, barley, wheat, oat and vetch + oat in 2005 and 2006. Overall results confirmed advantages of growing birdsfoot trefoil under spring crops, especially oat, a vetch-oat mixture and wheat for higher yield of green fodder.
