Effects Of Alternate Irrigation With Fresh And Saline Water On Soil Salinization Process And Wheat Productivity In North China Plain

In the North China Plain(NCP),sustainable development of agriculture is restricted by fresh water shortage and water quality deterioration.However,there are plenty of saline water in shallow aquifer waiting for crop use due to its negative effects on crop growth and soil salinization.Recently,a newly irrigation method for using saline water has been developed,that is to alternately irrigate crops with fresh water at sensitive growth stage and saline water at non sensitive stage.The experiments were conducted from October 2014 to June 2015 and from October 2015 to June 2016 at the Hengshui Dryland Agriculture Experimental Station to evaluate the effects of alternative irrigation with fresh and saline water(AIFS)on winter wheat productivity and soil salinization.In this study,five treatments with three replications were laid in randomized block design for 15 plots.Treatments included CK(no irrigation),AIFS1(irrigation at seedling stage with saline water,fresh water at turning green stage and saline treatment at flowering),AIFS2(irrigated with fresh water at seedling stage,saline water at turning green stage,and fresh water at tasseling stage),AIFS3(at turning green fresh irrigation was applied and at turning green saline irrigation was applied),AIFS4(at turning green stage saline water supply and irrigated at flowering-filling with fresh water).Soil water content,EC and pH was measured from soil samples and biomass accumulation also weighted manually.In the end of wheat growing season,the seed yields were also measured.The two years experimental data were used to verify the Aqua crop model to assess the long term effects AIFS on soil salinization.The results showed that:(1)There were no significant differences for soil electrical conductivity and pH values among all treatments after two years AIFS,but significant difference for soil water content among different treatments.(2)Irrigating winter wheat with saline water at non sensitive growth stage and fresh water at sensitive stage alleviated the salt stress on biomass accumulation and grain yield,and acquired the higher biomass and grain yield among five treatments.(3)The best irrigation model for alternately irrigating winter wheat with fresh and saline water was AFSI3(irrigated with fresh water at turning green stage and saline water at flowering-filling stage)due to higher WUE and moderate yields of winter wheat in the North China Plain.However,after AIFS saline water irrigation for long term(30years),we should arrange flooding irrigation with huge amount water to move salt in root zone to deep soil layers for decrease the effects of soil salinization processes on crop growth and harvestable yield.(4)Aqua crop is a robust tool to predicate crop productivity and soil salt accumulation of wheat irrigated alternately with saline and fresh water at different growing stages,and also is used to assess the long term effects of AIFS on crop productivity and soil salinization process.