Abstract: Natural zero-tillage is a new tillage method for paddy field, through which, the microrelief of earth surface can be varied artificially, and a paddy field ecosystem adaptive to the multiple cropping and rotation of low land and up land crops and characterized by the yearround symbiosis of fish, duckweeds and ducks can be established. This method can promote the exchange of matter, energy and information between inner and outer soil environment, harmonize water, heat, gas and nutrient, and through the effect of environment networks, intensify the buffering--regulating capacity between environment and organisms and promote the self-regulation capacity and ordered degree of soil.

Key words: Natural zero-tillage, Paddy field, Ecosystem