Changes Of Soil Quality Of Maize Straw After Returning To Field And Its Effect On Crop Seed Germination And Seedling Growth

In the conditions of maize straw total burning returning and crushing returning,,studying the soil respiration rate, organic matter content,soil microbial quantity and enzyme activity of maize seedling, jointing stage, the big stage, tasseling stage,mature period, exploring the changing rule of soil quality under two straw returning modes, clearing out the field soil quality differences and changes in the laws of straw burning and crushing. So that hope our research will provide theoretical basis and technical support for spring maize high yield cultivation. At the same time, in order to study the effect of plant allelopathy on different crops,provide theoretical basis of the comprehensive evaluation of maize straw returning on crop seeds germination and guide the agricultural production, the effects of maize straw aqueous extracts on seed germination and antioxidant activity,malondialdehyde content,proline concent and root vigor for maize, soybeans and wheat were investigated.The main results of this study as follows:In the conditions of maize straw total burning returning and crushing returning,the changes of soil quality are basically same under those conditions. It shows that the soil respiration rate, microbial biomass and enzyme activity reached the peak level at Maize Jointing Stage, and then with the advance of maize growth process, showed a downward trend.But the organic matter content showed no significant changes. So we should take proper measures to improve the soil quality in the late growth stage of maize, in particular, it’s more important to meet the demand for the formation of Maize Grain Filling Stage.Straw crushing returning is more beneficial to the improvement of the soil quality. The soil respiration and the organic matter content in the condition of straw crushing returning is higher than straw burning returning.At the same time, in the condition of straw crushing returning,the correlation among the physiological indexesof soil is stronger,the soil components are reasonable,those factors are more beneficial to the improvement of soil quality.So straw crushing returning is more worth to be advocated from the respective of experimental data.Different concentration of maize straw aqueous extract has different effect on the different crop seeds’ germination.One is that the treatments under different concentration of maize straw extract promoted the germination of maize seeds,increased the maize seedling root activity and proline content significantly;The second is the treatments under different concentration of maize straw aqueous extract promoted the germination of wheat seeds and significantly improved the wheat seedling root activity, pod content and proline content, but also increased the content of MDA. So the quantities of maize straw returning should be proper or lower when the maize and wheat rotating.The third is that high concentration of maize straw aqueous extract is unfavorable to the germination of soybean seeds besides the content of MDA and proline of soybean seedlings increased significantly,but the treatment of lower concentration made the MDA content of soybean seedlings decreased significantly and the POD activity increased significantly. Therefore it’s not conducive for maize and soybean rotation in the condition of high amount of maize straw returning.