Cultivation Experiment of Subsoil Improvement by Peat Layer Mix Plowing for the Upland Crop Field Which Have Thick Clayish Surface Layer —Subsoil Improvement for Peaty Paddy—Upland Rotation Field Spread Along the Basin of the Lower Stream of the River Ishikari(2)—

Abstract

This report summarizes the cultivation experiment results of subsoil improvement by peat layer mix plowing for the peaty paddy—upland rotation fie Id (upland crop use) which have too—thick clayish surface layer. 1) Soil tilth,soil porosity and surface permeability were improved by layer mix plowing. 2) Trafficability for tractor is not inferior to that of the fields of normal plowing. 3) The whole field ground did not subsided after layer mix plowing,but the degree of configuration is worse than that of the field of normal plowing.