Drip irrigation under plastic mulch can effectively improve conditions of soil water and heat conditions

and increase crop yield. Moreover

change range of soil water

heat and crop yield as well as water supply from groundwater are maily effected by irrigation amount. To explore the effect of irrigation on soil and water consumption to groundwater recharge ratio of cotton in the growth period

four treatments with different irrigation amount（3 000 m3/hm2

3 750 m3/hm2

4 500 m3/hm2

5 250 m3/hm2）were conducted and the effects of irrigation amount on soil temperature and water supply from groundwater were investigated during growth period of cotton by the balance plots. The results showed that

at a given irrigation amount

the shallow soil was more easily affected by the atmospheric temperature; under the same meteorological conditions

soil temperature and effective accumulated temperature at the same layer decreased with increase irrigation amount

when the irrigation amount was increased by 75%

effective accumulated temperature decreased by 11.3%

while the temperature changes were relatively small; the greater the irrigation amount

the greater the water consumption of cotton and the amount of water in the groundwater supply. When the irrigation water was increased from 3 000 m3/hm2 to 5 250 m3/hm2

the water consumption of cotton increased by 146.3%

groundwater recharge rate increased by 540%

the water supply in the sensitive period of cotton increased by 152.93 mm

and the amount of groundwater recharge in the water sensitive period was the greatest

but daily groundwater recharge increased with the increase of cotton growth period

and the water use efficiency of each treatment was not significantly different. Furthermore

it was found that at the conditions of higher soil temperature in summer (flowering and boll opening stage) and the lower irrigation amount

the amount of water supply from groundwater in the night was greater than or close to that in the daytime. The results of this study will provide an effective basis for using of agricultural water resources rationally and efficiently and optimizing the irrigation system of drip irrigation under plastic mulch.