Abstract: On the basis of the chemical fertilizer reduction, this study explored the effects of paddy integrated ecological system on the physical and chemical properties and humus of paddy soils. Four experimental fields were selected around Chaohu lake basin. The large-scale integrated ecological model (Early rice crayfish rotation, later rice-duck mutalism) of paddy field was compared with conventional cultivation models (idle, single-season rice cultivation and double-season rice cultivation), with a cycle of 2 years. The results showed that there were differences in soil bulk density and total porosity components in the four types of planting models（P<0.05）. Compared to the conventional planting models, PES was effective in soil texture, which improved sand differentiation rate and soil total porosity, and reduced soil bulk density. In PES model, the soil fertility factors increased significantly. The activity and degree of humus were improved. At the same time, the degree of condensation and molecular complexity of humic acid in soils decreased significantly. The PES model has improved the physical structure and fertilizer retention capacity of paddy fields and increased the economic income of planting, which is worth popularizing.

Key words: compound cultivation, bulk density, nutrients, humus