Abstract
1. A field experiment was conducted during 1963〜64 to study the effect of irrigation on growth and yield of forage crops on the mineralsoil of the warmer district, compared with prevalent volcanicas hsoil, changing the method and the amount of water application for each irrigation. 2. Effect of irrigation to mixed forages was high in summer season and it was remarkable in Ladino clover which increased length of leaf-stalk and leaf area. The dry matter yields in irrigated plots were 40% more than that in non-irrigated plot. 3. Soil erosion and the running off of the added fertilizeres by the irrigation water of contour ditch method were very slight. So this method seemed to be very useful to the pastures in slope land, though the dry matter yields were 1〜6% less than that in perforated-pipe method. 4. Water requirement changed with season, and it is conjectured that about 3.5〜5mm per day in May to early July and 5.5〜6.5mm per dayin midsummer are adequate amount of water supply fort he grass-legume mixtures in warmer district.
