Effects Of Straw Incorporation And Plastic Film Mulch On Soil Carbohydrates

The planting pattern of double ridges and furrows mulched with plastic film significantly preserved heat and moisture, inhibited water evaporation and increased crop yields, has been widely used in rain-fed agricultural region of the loess plateau at semi-arid area of China. Maize straw contains abundant nutrients which required for crop growth, after applied into the soil, it can not only provide nutrients for crop growth, but also increase soil organic matter, improve soil environment. But the decomposition of maize straw needs a long time because of there is no appropriate water and temperature conditions in rain-fed agricultural region of the loess plateau at semi-arid area of China.So we integrated the advantages of straw incorporation and plastic film mulch, trying to find a new planting pattern that can increase soil fertility and crop yield. However, the background value of total organic matter is high, the Change is not obvious and has a lag, so it cannot be used as a soil quality assessment standard simply. Soil carbohydrates are important components of variable library of soil organic matter. They are including neutral sugars and amino sugars. The content and source of soil carbohydrates is easily influenced by climate, temperature and management measures. It can be used to indicate the change of organic matter and its source.The experiment was conducted in Yuzhong, Tongwei, Huining countries of Gansu province from 2008 to 2013. Including four treatment (1) no straw incorporation+no plastic film mulch (CK); (2) no straw incorporation+plastic film mulch (M); (3) straw incorporation+no plastic film mulch (S); (4) straw incorporation+plastic film mulch (SM); three replications and random arrangement.Main results as follows:1. Plastic film mulch has significantly increased crop yield, the grain increased about 50.39%-103.01%and 65.79%-110.98%, the shoot biomass increased about 37.40%-96.53% and 49.98%-81.97%, the root biomass increased about 32.48%-57.32% and 28.12-45.25% of SM and M treatment. The plastic mulching increased harvest index, but it no effects on root-shoot ratio.2. Plastic film mulch reduces the soil pH, the range from 2.4% to 6.7%, but straw incorporation has no significantly impact on it. Plastic film mulch has decreased trend of SOC, TN, LOC content of plough layer soil. Straw incorporation has increased trend of SOC, TN, LOC content of plough layer and S treatment has significantly increased about 12.06%-l3.32%.3. Plastic film mulch has significant increased mineral N content of plough layer soil, M and SM treatment increased about 2.98-5.08 and 1.52-2.51 fold respectively, however straw incorporation has no significantly influenced. In the corn harvest, plastic mulching decreased MBC and MBN content of plough layer, but straw incorporation significantly increased them.4. Plastic film mulch has no effect on neutral sugars and amino sugars content of plough layer soil, however straw incorporation significantly increased them. Neutral sugars increased about 20.13%-28.30%,18.28%-29.83%, amino sugars increased about 20.93%-40.63%,16.28%-36.59% in S and SM treatment. The percentage of neutral sugars and amino sugars in soil organic carbon also increased significantly. The results suggest that straw incorporation increased the content of soil active organic ingredients.Plastic film mulch has significant increased the value of (Gal+Man)/(Ara+Xyl) and (Rha+Fuc)/(Ara+Xyl), indicating microorganism has a relatively larger contributoin. Straw incorporation (S) significantly reduced the value of (Gal+Man)/(Ara+Xyl), indicating plant residues has a larger contribution.Straw incorporation treatment(S,SM) has significantly increased the value of Glu-N/Mur-N, showing fungus is sensitive to the plant residues than bacteria. On the contrary, Plastic film mulch treatment (M, SM) significantly increased the Glu-N/Gal-N values, and straw incorporation treatment (S) had no significant effect on its.In summary, plastic film mulch can significantly increased crop yields. While the straw incorporation has a tendency to increase the soil nutrient content, and significantly improve the content of carbohydrates and activity of soil carbon library. So the pattern of plastic film mulch and straw incorporation coupling will be a new sustainable planting pattern in semi-arid regions.