Effect On Soil Rganic Carbon And Straw Decomposition Rate Under The Condition Of Burying Corn Stalks

The annual production of straw is huge in our country, the production of straw is close to 700 million tons in 2009, main types of crop straw are rich, the number is huge, the annual production of straw accounts for about a quarter of the world total. The corn is the main production of our crops, the corn planting area of Jilin province accounted for about 12% of the world and 65% of the total crops area of Jilin province, the production of corn straw is between2300-25 t million each year. The researches have pointed out that the direct combustion and waste burning of straw in China accounted for about 55% of the available total, that number of Jilin province has been up to 80%.This way of extensive used not only caused the waste of straw resources but also caused serious air pollution, especially the straw burning will release a large number of harmful substances such as CO, SO₂, NO_X into the air.This paper is about the straw resource waste problems during the process of agricultural production of Jilin province, to study the straw decomposition change law with time, straw decomposition influence factors and the influence on soil SOC, in order to provide the basis of promoting the most effective way of straw returned to soil and soil fertilizer. Field experiment is divided into seven kinds of processing and set up four groups of different controls. Results show that:?1? The rule of straw decomposition is that it is fast early but slow late, the decomposition can achieve 60% at the 90 days before, the rate quickly reduced after. The deeper the straw embedment depth, the lower straw decomposition rate. The maximum difference value of different buried depth became at the 60 th day, the straw decomposition rate is 7.42% higher at buried 5 cm depth than the buried 20 cm, the gap becomes narrowed later. The straw decomposition rate increased by straw mixed soil and organic fertilizer, the decomposition ratio with mixed soil and organic fertilizer processing is 7.63%, 4.49%more than the compared at 60 th day respectively, the difference of decomposition rate reduces later. The impact of straw forms on the decomposition rate is relatively small, the straw decomposition is the fastest at length of 5cm. The straw decomposition rate reduces under the double straw returned, the straw decomposition rate has a 14.19% lower than the single straw returned at 120 th day.?2?The SOC increases obviously by straw embedment, the lower layer of straw mixed soil increases 2.65g/kg, which is a largest rise, the change tendencies of the components of humus FA, HA, Hu are basically consistent with the SOC. The PQ value Increased with straw returned process, the difference is obvious.