| Heilonggang region is the main producting areas of food crops in Hebei Province, and winter wheat and summer corn are the main food crops. However, the water resources of per capita is only 1/7 of the national average in this region, and the water resources is in short supply, which is becoming the main factor of restricting the agricultural production. Meanwhile, there are lots of salt water resources in this region. Therefore, to study on how to reasonably develop and utilize of the local salt water resources for agriculture irrigation, saving fresh water resources, has an important practical significance to the local agricultural production.Based on the saline water irrigation test of dry land farming research institute of Hebei academy of Agricultural and Forestry Sciences with irrigating 1.0 g/L、2.0 g/L、4.0 g/L、6.0 g/L、8.0 g/L and dry land in 2006~2012 year, SWAP was adopted to analysis sensitivity、calibrate and validate using the data of soil water content 、 salinity concentration and crop yield with various irrigation water concentrations. As a result, the calibrated model can well reflect regional soil water and salt conditions, with reliability of the simulation.On this basis, the suitable concentration of salt water irrigation had been explored. This article simulates the long-term saline water irrigation taking an example of silty clay loam of experimental zone in 1980 ~ 2010 year. It is concluded that the concentration of salt water irrigation for a long time should not be greater than 4.0 g/L with the 0.70~0.13% of soil salt initial value, which is consistent with the existing field trials in this region. In terms of storage salt and salinity tolerance of winter wheat and summer maize in the growth period, when the concentration of irrigation water is equal or less than 4.0 g/L, the annual average storage salt of 2.0 m soil column and 20 cm soil column plough layer are equal or less than 0.111% and 0.125%, respectively, and the soil is in the mild soil salinization levels. At this point, the soil salinity of the plough layer from the winter wheat reproductive stage was less than 0.40%, and soil salt content of summer maize seedling the arable layer was less than 0.20%, which are both lower than crop salt tolerance values, and the crop will not be suffered obvious salt sress. However, when the irrigation water concentration is more than 4.0 g/L, the topsoil salinity is higher than salt tolerance value of winter wheat and summer corn in the growth period, and inhibits the growth of crops. Meanwhile, along with the increase of concentration of irrigation water, soil water and salt on the bottom of the flux is also gradually increased.At the same time, this paper also preliminarily discusses how to further optimize saline water irrigation schedules. Through the simulation analysis of different irrigation schemes of 2006~2012 year, it comes up with that winter wheat can try to irrigate 3 times(seeding water, jointing water and flowering water)in this area. Meanwhile, the irrigation amounts of saline water reduce from 75 mm per acre to 40 mm per acre. Compared to the non- limited irrigation water, the total average annual yield of winter wheat and summer maize increased 15.26%, and the annual average water use efficiency increased 14.45%. So that saving fresh water and salt water resources are 2.05 million m3 and 4.10 million m3 every year, respectively. Optimizational saline water irrigation can reduce the potential danger of deep seepage to the lower aquifer. |
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