Back S. Iwaishi
International Nature Farming Research Center, 5632 Hata-machi Nagano Pref. Japan
Full Paper (PDF File: 30KB)
Abstract
It was confirmed in 26 paddy fields from central to eastern parts of Japan that there exist paddy soils whereby the growth of rice was promoted while the weeds were controlled by cultivation practices. The advantages of rice or the weed (M. vaginalis) and the damages by pest (L. oryzophilus) changed with alternations of the application depth of rice straw with different decomposing extent and quantity. The adverse effects from the raw materials wereercome by mulching organic materials on the soil surface with positive effects of promoting activities of earthworms, improving soil structure and depressing weeds. Moreover, applications of organic materials confirmed the growth promotion from weed control by earthworms and activities of photosynthetic bacteria. A long-term experiment conducted in the fields with M. vaginalis as the main weed and without any pesticide applications also confirmed that there exist paddy soils whereby rice growth is promoted and weeds are depressed. It is possible to adjust the soil nitrogen concentration and earthworm population by applying organic materials and changing puddling methods in addition to soil water management for weed control.