Effects of Winter Irrigation Method on Soil Moisture,Salt and Temperature Distribution in Cotton Fields of North Xinjiang

Field plot experiment was conducted to investigate the effects of winter irrigation method on soil moisture,salt and temperature in cotton field of north Xinjiang,and to find out a suitable winter irrigation method and the best irrigation amount for cotton fields.In the experiment,soil moisture,salt and irrigation water were comprehensively regulated and controlled.Using fields without winter irrigation as control,cotton fields were drip irrigated or flood irrigated with 5levels of irrigation amounts(i.e.1 200,1 800,2 400,3 000and 3 600m3/hm2)in winter.The dynamic changes of water,salt and temperature after irrigation in the 0-300cm soil layer were compared and analyzed.The results showed that with drip irrigation,water infiltrated uniformly and slowly into the soil,and when irrigation amount was low,water in the plough layer tended to evaporate readily,resulting in water loss.With flood irrigation,water quickly irrigated,resulting in non-uniform water infiltration and flooding in the plough layer which was not favorable for farming in the next year.Taking together the salt leaching effects of the irrigation methods and irrigation amounts,it was concluded that both drip irrigation with high irrigation amount and flood irrigation with high irrigation amount could play a vital role in salt suppression and an amount of 3 000m3/hm2 was better in maintaining soil moisture and suppressing salts.