The evaluation of the safe yield of ground water must be based on that the disaster ground subsidence don't take place. The control of ground subsidence is the control of disaster ground subsidence.

The egg mass rate, megalopa yield, growing rate and the survival rate of the young Chinese mitten crab are promoted significantly while proper ratio ground water is applied to the cultivation.

Compared with submerged irrigation, the growth of root, accumulation of above-ground dry matter, grain yield and water use efficiency were decreased significantly under dry cultivation.