Effect Of Different Green-cover Models On Salt Restraint

At present, soil salinization and secondary salinization phenomena are becoming more and more serious in the world, it has already become main obstacle that influences the agricultural sustainable development and ecological good circulatory. This article chooses the soil irrigated in Qin Wang Chuan as the object of research, through implementing 7 kinds of different planting models, measures content of soluble salt, Cl^-, SO₄^2-, Ca²⁺ , Mg²⁺ , Na⁺ and K⁺ in soil at different time , aims at offering basis of theory and practice for preventing soil secondary salinization, and explores some effectual measures for preventing and curing the salinization in the new irrigated area. The main results on study are as follows: 1. From Apr.1st to Oct. ninth, when two-year-old Onobrychis viciaefolia ,one-year-old Onobrychis viciaefolia ,Triticum ,Triticum aestivum/ Vicia villosa ,Triticum aestivum/ Brassica campertris ,Triticum aestivum-Vicia villosa and Triticum aestivum-Brassica campertris are planted, their content of soluble salt in 0～20cm soil layer are lower than that in uncovered soil, in the period of harvest , they decrease 0.361%,0.331%,0.141%,0.327%,0.312% and 0.317% respectively. It shows that green cover has obvious function of restraining salt. 2. Implementing7 kinds of different planting models also change content of different salt ions .The content of Cl-decreases 0.033%～0.070%, SO42-drops0.048%～0.107%, Ca2+ reduces 0.033%～0.070%, Mg2+ lowers 0.0007%～0.0135%, Na+ decreases 0.004%～0.040%, and K+ lowers 0.0002%～0.0013%. 3. With vertical-section analysis, in the later of experiment, naked terra and wheat land make content of soluble salt high in 0～20cm,and decreasing with deepening of soil-layer; the content value of planting two-year-old Onobrychis viciaefolia ,one-year-old Onobrychis viciaefolia ,interplanting and sequential cropping in the every soil-layer is equal; in harvest, only planting wheat and interplanting display content of soluble salt is high in middle-layer (20～60cm) and low in surface and down layers(0～20cm,60～80cm). 4.There is different influence on soluble salt through different green cover models, but ANVOA analysis, the difference isn't remarkable, 5.Both interplanting or sequential cropping Vicia villosa may restrain content of soluble salt , Cl^-, SO₄^2- , Ca²⁺, Mg²⁺, Na⁺ and K⁺ to rise . With density increased, the biology quantity of the two planting models gradually increases, moreover, the production of interplanting is more than that of sequential cropping, and the function of restraint also increases. 6.Soluble salt (Y) and salt ion (X ) have linear relation , analysis of step regression,Ca²⁺ has the largest influence on soluble salt in uncovered soil ; SO₄^2-, Cl^–have the largest influence on soluble salt when green cover are used. 7. For preventing secondary salinization problem in Qin Wang Chuan, we suggest that interplanting or sequential cropping be accepted; considering such factors as busy farming season situation, grass yield, etc., we propose adopt the planting mode of interplanting.