Researches on the ecological thresholds of Suaeda salsa to the environmental gradients of water table depth and soil salinity;

Taking the rodent community and major afforestation tree species in artificial forest system as research objects, the concept of ecological threshold of artificial forest community was put forward.

The analysis on the present greening of Zhuhai city is made using carbon-oxygen balance,ecology threshold value and the oxygen requirement etc,and some suggestions are put forward to improve the city ecosystem environment quality and the city ecological effect continuously.

Field experiments were conducted in paddy to study the functional relationships between the weedy or weed-free days and the yield loss rate of rice transplanted by throwing,and determine the threshold period of weed control in rice field.