Leaching and Distributions of Soil Water,Salt and Nitrate in Cotton Field under Drip Irrigation with Saline Water

The effect of irrigation water salinity and irrigation amount on leaching and distributions of water,salt,and nitrate in soil were evaluated with a field experiment under drip irrigation conditions in 2009.Results show that soil salinity and water content in 1-m depth were increased significantly with the increase in irrigation water salinity.When irrigation amount was increased,salt leaching were promoted from the top soil to deep soil,but the average salinity in 1-m soil were not increased significantly.Salt leaching from 1 m soil was increased significantly with irrigation water salinity and irrigation amount increased.Under low irrigation amount,there were no significant differences between moderately saline water and fresh water treatments for water and nitrate leaching;but the leaching of water and nitrate in moderately and saline water treatments were significantly higher than those in fresh water treatment under high irrigation amount conditions.Therefore,irrigation water salinity level and irrigation amount should not excessive when saline water is used for drip irrigation.The optional irrigation water salinity level and irrigation amount are benefit to control salt accumulation and to minimize water and nitrate leaching loss.