Simulation And Inversion Of Soil Water And Salt Transport And Crop Growth Under Saline Water Irrigation

Due to the continuous expansion of the deep groundwater funnel and the serious shortage of groundwater resources in Heilonggang area,agricultural irrigation is an urgent problem to be solved.In this study,saline water irrigation method was proposed to alleviate the shortage of fresh water resources in this area.Based on the data of irrigation water with different salinity(1g/L,2g/L,4g/L,6g /L,8g/L)from 2010 to 2011 in dry farming and water-saving agricultural experimental site of Hebei Academy of agriculture and Forestry Sciences,SWAP model including water transport module,solute transport module and crop growth module(WOFOST)was established.The calibration verification and parameter sensitivity analysis of swap agricultural hydrological model are carried out by using parameter estimation software PEST(Parameter Estimation).The error analysis shows that the hydrological model can better simulate the process of water and salt transport and crop growth.The main research contents and results are as follows:(1)Long term saline water irrigation is bound to aggravate soil salinization and affect the growth and development of crops.In order to control the negative effects of saline water irrigation,the long-term saline water irrigation with different salinity from 1980 to 2013 was simulated by using SWAP.The threshold of suitable irrigation water concentration was studied from the aspects of water and salt balance components,soil water concentration variation,soil salt content,salt storage and crop yield.It was proved that long-term saline water irrigation should not exceed 4g/L.(2)In this paper,alternate irrigation with salt and fresh water(AISF1,AISF2,AISF3,AISF4,AISF5,AISF6,AISF7,AISF8,SW)was used to identify the salt water sensitivity during crop growth period,and 1g/L salinity fresh water(CK)irrigation was used as the control group,The salt water tolerance of crops at different growth stages should be correctly identified.The results showed that the salt tolerance from high to low was grain filling stage > jointing flowering stage > overwintering stage.(3)In this study,the limited irrigation mode was discussed,and the total fresh water(CK)irrigation with 1g / L salinity was used as the control group to explore the changes of crop yield and water use efficiency(WP)under the limited irrigation mode(CK-limited,AISF1-limited,AISF2-limited,AISF3-limited,AISF4-limited,AISF5-limited,AISF6-limited,AISF7-limited,AISF8-limited,SW-limited)after reducing the irrigation amount,so as to fully analyze the sensitivity of crop growth period to salinity.These results verify that the appropriate irrigation time of saline water is very important to ensure the yield of winter wheat,and help farmers in saline areas to improve crop yield and economic returns.