Effects of different measures on soil desalination andcotton physiological characteristics
WEN Lijun1,2, SHI Wenjuan1*, HE Zijian1, GAO Zhiyong1, SHI Xiaoxiao1
1. State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi′an University of Technology, Xi′an, Shaanxi 710048, China; 2. Gansu Provincial Water Resources and Hydropower Planning Survey and Design Research Institute Co. Ltd., Lanzhou, Gansu 730000, China
Abstract：In order to investigate the effects of different improvement measures on soil desalination and cotton growth in the field with drip irrigation under mulch, which would provide helpful and important information for improving saline-alkali land in Xinjiang, China,three improvement measures including the biological method with intercropping(alfalfa + cotton, cumin + cotton, Suaeda salsa + cotton), the chemical method with different doses of gypsum in soil(0.75 kg/m2, 1.50 kg/m2, 2.25 kg/m2), the comprehensive method combined with biological and chemical methods(alfalfa + gypsum, cumin + gypsum, Suaeda salsa + gypsum)were adopted, and the no-measure in cotton field is considered as controls and the total is 10 treatments. The results showed that compared with the control, the three improvement measures were all effective in decreasing soil salt content and increasing cotton yield to some extent. Among the treatments, the intercropping with alfalfa and cotton performed best, with the desalination rate of 56% and 20.9% for the whole soil layer and the bare soil strip between plastic mulches respectively; the treatment for the comprehensive method with Suaeda salsa combining gypsum made the highest yield by 22.4% increase. The accumulation of Na+ and Cl- occurred at the bare soil strip for chemical and comprehensive improvement measures at the end of the growing period, but this occurred at the wide line for biological improvement measures. The transpiration rate, stomatal conductance and photosynthetic rate of cotton were increased for all improvement measures compared with the control, and their main orders were: comprehensive meausres > chemical measures > biological measures > controls. All measures improved water use efficiency and irrigation water efficiency to some extent compared with the controls, their main order were: biological measure < chemical measure < comprehensive measure. In general, the different improvement measures would lead to quite different effects, the biological improvement mesures for intercropping with alfalfa and cotton will be the best method if soil desalination effect is only considered,and, the comprehensive measure for Suaeda salsa combined with gypsum treatment will be the best method if yield increase and water use efficiency are consi-dered for cotton field with drip irrigation under mulch in Xinjiang.
