Objective The effect of soil moisture on plant growth characteristic and grain yield of no-tillage rice was investigated to identify the optimal soil moisture for no-tillage rice production.

Method Pot experiments were conducted in the early and late seasons of 2013.In each season, a hybrid rice cultivar Jiyou716 was cultivated under the saturated soil moistures of 95%-100% (W100), 80%-85% (W85) and 65%-70% (W70).

Result and conclusion The grain yield, biomass and harvest index of no-tillage rice under W70 were significantly lower than those under W100 and W85.The reason why the grain yield decreased under W70 was that panicle became small and seed set decreased.The biomass and transportation under W70 were significantly inhibited.The tiller dynamic of no-tillage rice was divided into two stages, and the tiller number first increased and then decreased.The tiller number decreased when soil moisture reduced, and there were significant differences among the three treatments at peak tillering stage, but no significant differences in the end.The plant height decreased when soil moisture reduced, and there were significant differences among the three treatments.The area, length and width of three leaves from top decreased when soil moisture reduced at the elongation stage.The soil water deficiency first influence the leaf width, then the leaf length, and lead to the leaf area decrease in the end at the elongation stage.The area, length and width of three leaves from top under W70 significantly reduced at the heading stage.Therefore, the soil moisture should be not less than 70% of saturated soil moisture in no-tillage rice cultivation.