On the winderosion of cultivated field. (1)

Abstract

1. This study was made in order to find out the relations between wind erosion and the width of furrows.2. It was found that the wider the furrows became the higher its crest rose. But no definite ratio of the width of the furrow. to the wave height, was found.3. As to the relation between the width of the furrow deviled by the wheat height and the wave crest height devided by the width of the furrow, the latter increases as the former increases. When the former becomes 12 to 15, however, the latter increases more. This is perhaps because at the furrow in the wheat field where the width is around 12 times the wheat height, the wind velocity rises above the velocity within the limit of which the wind does not blow off earth soil owing to the decrease in the effect of protection against the wind.4. The inclination angle of the sand ripple in the wheat fleld is quite contrary to that on a sand dune; it is acute at the windward and obtuse at the leeward.And in the process that the sand ripple is formed in the furrow in the wheat field, the most of the cultivated sand grains smaller than 0.1mm in diameter are lost, while pebbles and coarse sand are left accumulated, changing cultivated lands sand fields.