Studies on the Soil Amendment on the Slope Lands by Application of Organic Matter. : I. Variation of Soil Water of the Slope Lands.

The soil water tension at the depth of 15,30 and 60 cm in the various places of the orchards on slope lands was surveyed from spring to autumn. At the depth of 60 cm of lower parts on the sharply sloped land, the soil water tension did not increase for a long time after rain fall, and, among the places surveyed, the longest time of over-humidity (tension value below 31 cm water heights) was shown. At the early stage of draught, the begining of increase of soil water tension was earlier at the upper part of the slope than the lower part, but the increasing speed of the former thereafter was not always higher than that of the latter. In the orchards planted on the ditch, which was dug horizontally and filled with rough organic matter, the increasing speed of soil water tension at the inner part of the ditch was considerably higher than that at the outer part of the ditch, suggesting that the root system of the fruit tress concentrated in the planting ditch.