Abstract: There is a positive correlation between available silicon content and pHvalue or clay content of paddy soil in Liaoning province. The silicon supplying capacity of soil in judged by available silicon content and related factors is different for various rice fields in Liaoning province. Soil with strong silicon supplying capacity mainly distributes in southern and partly in central or northern rice-planting belts, and that with weak silicon supplying capacity mainly distributes in rice-planting belts of eastern mountainous region and east Liaoning. Pot experiment with regression design shows that there is an obvious interaction of Si and Nor Si and P. With proper combination of N, Pand Si fertilizers, a maximum rice yield is obtained. N, Pand Si can all affect the ratio of rice/straw, and under the interaction of these three elements, the maximum rice yield will occur within the rice/straw ratio of 1.0—1.1.

Key words: Paddy soil, Silicon supplying capacity, Rice yield, precipitation exclusion, warming, denitrification potential., N₂O flux, subtropics