The Effects Of Coated And Irrigation On Straw Decomposition And Soil Enzyme Activity After Different Straw Counters-field

Straw as an organic material be put into the soil, can improve soil fertility,organic matter and change soil structure. In gansu agricultural university campus on irrigation soil,took the last season farmland crops of corn, wheat and pea stalks as the research object, used the nylon mesh bags method, studied the soil heat and water, enzyme activity, dynamic changes and different straw decomposing after straw returned, in order to providing scientific basis and theoretical reference to semi-arid regions of straw utilization.The studying results showed that:1, Compared with the treament CK, straw returned can significantly increase the soil enzyme activity. S treatment of soil invertase, urease, alkaline phosphatase and catalase activity was higher than CK treatment. SC treatment on soil had obvious heat preservation effect, can significantly increase the four kinds of 20 cm of soil enzyme activity, SW treatment on sucrase, urease and phosphatase activity effect significantly, can increase its activity. Corn, wheat and pea straw returned in SCW processing of enzyme activity is relatively highest. In the depth of 10 cm, peas, straw returned the soil invertase activity, the biggest overall for pea straw > maize straw > wheat straw; Soil urease activity in the largest corn straw returned, overall for maize straw > wheat straw > pea stalks; Soil alkaline phosphatase activity in the largest corn straw returned, alkaline phosphatase activity in the soil for corn stalk general straw > wheat straw > peas; Soil catalase activity of wheat straw > maize straw > pea stalks. Returning in 20 cm depth, soil invertase activity of pea straw > maize straw > wheat straw; Soil urease activity of wheat straw > maize straw > pea stalks; Three kinds of soil catalase activity of straw returned to the wheat straw > maize straw > wheat straw.2, Corn stover, wheat straw and peas, after the straw returned in 120 days ago, the decomposing rate of straw was quickly, returning after 120 days, the rate slowly, the lar gest of the three kinds of straw decay rate were 0.68% and 0.62% and0.70%. Returning in the depth of 10 cm and 20 cm, three kinds of straw decay rate for pea stalks>maize straw > wheat straw.3, Different treatment effect on soil water content is different, SC processing of high temperature and drought, had better water keep moisture of lower soil. SW treatment can increase the moisture content of the soil after straw returned. SCW processing is more advantageous to improve the soil to keep moisture and water resistance. In 10 cm,overall for maize straw straw > wheat straw > peas. In 20 cm, wheat straw > maize straw > pea stalks.4, Straw returned to soil temperature in a certain range. In 10 cm with corn straw returned the highest soil temperature, overall for maize straw > wheat straw > pea stalks. In 20 cm, with wheat straw > maize straw > pea stalks.5, The soil PH declined afte different straw returned, but overall remain slight neutral range, there was no significant effect on the rate of straw decay. Three kinds of straw returned after returning soil PH value in the depth of 10 cm with corn straw returned the highest overall, 20 cm with wheat straw counters-field supreme, showed the peas lowed soil PH obviously after straw returned.6,The temperature and humidity of the soil had significant effects on straw decomposing, achieved significant correlation, but in a certain range, the soil PH value of straw decay rate had no significant impact. In northwest semi- arid areas, SCW treatment is helpful for raising temperature, soil water can accelerate the decay of the straw, release of nutrients, so as to increase the effect of straw returned, to raise efficiency of utilization of straw resources,had important significance for the sustainable development of the soil.