Studies on Aged Paddy Soils (Part 1) : Influence of Alternating Rice Plant with Upland Crop on Aged Paddy Soils

Abstract

In reference to increasing the yield of aged paddy soil, we studied the influence of "ARASHI" (drying paddy field soil in summer for upland farm on the rice-yield of next year. In this paper we investigated the difference of chemical and physical properties between the paddy soil and "ARASHI" soil in the low-yield area. The results obtained is as follows : 1) On the Chichibu palaeozoic series, "ARASHI" promoted weathering of aged paddy soil, changing fine sand into clay, and increasing free iron oxide. At the same time, the rotted product in soil humus changed into the true humic acid, forming the silica-humic complex. These products seemed to retard the development of hydrogen sulfide, and to increase the rice-yield. 2) On the Granite, "ARASHI" did not changed chemical and physical properties of aged paddy soil, and did not promoted the humification of soil. Consequently it seemed not to keep the immaturity of soil, and not to increase the rice-yield.