STUDIES ON REFORMS IN CROPPING SYSTEMS OF SINGLE CROPPING RICE IN FUJIAN’S MOUNTAIN REGIONS

In comparison with single cropping, double cropping gave significant biomass and economic yields. Three kinds of double cropping, namely spring soybean-late rice, spring tobacco-late rice and soring soybeaa intercropping with corn-late rice, are recommended in fields well-irrigated but not suitable for the growth of double cropping rice owing to the limitation of solar energy.The double cropping of early riceautumn corn is suitable for fields where the crop after early rice is apt to suffer from drought. Fields for double cropping rice should be kept relatively stable in area so as to stablize rice production. Where the acreage per capta is somewhat larger and there is a limited supply of solar energy, maintaining single-cropping rice to some extent is still necessary, for the purpose of alleviating labour shortage and doing farm work in the right season. In general, soil fertility is somewhat higher after double cropping than after single cropping.And soil fertility is also somewhat higher after double cropping of rice and an upland crop than after doubling cropping of rice.