Effects Of Total Amount Of Straw Returning With Different Deep On Soil Humification Characteristics And Fertility

Crop straw is a very important agricultural resources, crop straw not only contains a lot of cellulose and lignin, but also contains large amounts of nitrogen, phosphorus, potassium and other plants must, straw retuning as one of the effective way to use straw, not only makes full use of straw resources, reducing transportation and handling costs, solve the problem of repeated burning of straw,but also improving the local soil conditions and soil fertility, greatly promoted the recycling of agricultural resources.In this paper, through the culture experiment in the field, study the effect of burial depth of straw returned on soil humification characters and corn yield. Using picocell straw returnning experiment, 0~15cm, 15~30cm and 0~30cm soil added full amount of straw to study the effect of different depths on soil humification characters and corn yield. By two rows of ridge planting and straw returning combined, study the planting and straw isolated models on the effect of soil humic characteristics and corn yield. The results are as follows:(1) Through the acquisition of Jilin Agricultural University experimental field 0~15,15~30,30~45cm soil layer, were added 0.44%, 0.88%, 1.32%, 2.64%, 5.28% proportion of straw in situ field culture test, after two years of decomposition, soil organic carbon and humus carbon content increased with increasing amount of straw, soil accumulation of different manifestations of 0~15cm <15~30cm <30~45cm. In the different layers,the soil CO2 content increases with depth, indicating poor soil oxidation conditions in deep soil layer, straw decomposition is slow, intermediate products are more, this conducive to the accumulation of soil organic matter and humus. Soil humic acid and fulvic acid ratio increases with depth, indicating deep straw can improve the quality of soil humic acid. From the changes of soil enzyme activity, the straw also improve the soil catalase, urease and invertase activity of each soil layer. High amount of straw returning in deep soil layer can make the soil micro-aggregates change to large aggregate structure, enhance the role of soil aggregates,the effect of each grain size micro-aggregates content more significant.(2) By setting 0~15cm, 15~30cm and 0~30cm soil in full the amount of straw to study its effect on soil humification characteristics and corn yield.The results showed that straw returnning have increased soil organic carbon and humus carbon content of each component, and with the increase of straw age increases, the 15~30cm soil layer have largest accumulation, indicating that deep straw is better. Adding straw also increased soil catalase, urease and invertase activity. After 0~15cm and 0~30cm soil straw are causing a decline in maize production, while 15~30cm maize production has increased, indicating deep straw have no adverse effects on maize.(3) By two rows of ridge planting and straw returning combined, study the planting and straw isolated models on the effect of soil humic characteristics and corn yield. The results showed that planting and straw isolated model can also increase soil organic carbon and humus carbon content of each component, And with the increasing amount of straw increases. The soil catalase, urease and invertase activity also improved. In this model can promote root growth of maize and the maize production also increased, but not significantly different from the control.This indicating that Planting and straw isolated model have not disturb the growth of corn and the production of maize did not declined.