Biological traits on corn straw interlayer in improving saline-alkali soil

Abstract: Many measures have been adopted to improve saline-alkali soil in recent years, but the effects of different measures have advantages and disadvantages. Water conservancy facilities improve quickly and effectively, but the cost is high. Chemical modifiers are palliatives and not conducive to the sustainable development. It is necessary to explore a better measure to improve saline-alkali soil. It is easy for crop straw to cut off the continuity of the capillaries and partition the phreatic evaporation. The salt accumulation has been prevented in the surface of soil and a good physical and chemical soil environment is created for the crops to the normal growth and development. And burying straw into soil also prevents the salt in the deeper soil to return to the surface layer. Tongliao City is the corn production base in Inner Mongolia Autonomous Region and even the whole nation. The corn planting area is more than 1 100 000 hm2 every year, and there is wide source and large storage capacity of corn straw. It is necessary to study the effect of corn straw interlayer on improving saline-alkali soil. In the experiment, corn straw interlayer was made in different soil depths (10,15 and 20 cm) and different dosages (30 000, 45 000 and 60 000 kg/hm2) using corn stalks in saline-alkali soil. The soil was collected from Huatugula, Tongliao City in 2008 and then the barley was planted in the soil from 2009 to 2011. The paper studied the microorganism number and the enzyme activity in saline-alkali soil, and the impact of corn stalk isolation layer on saline soil's biological traits and barley yield. The results showed that the numbers of bacteria, actinomycetes, fungi, nitrite bacteria and cellulolytic bacteria, and the activities of urease, protease, amylase, cellulase and catalase significantly increased (P<0.01), while polyphenol oxidase activity reduced in alkali soil with corn straw interlayer (P<0.01). With the increasing of corn stalks' quantity, the numbers of microorganisms and the activities of urease, protease, amylase and polyphenol oxidase all increased (P<0.01), while the activities of cellulase and catalase did not change significantly. With the increasing of corn stalks' burying depth, the numbers of microorganisms and the protease activity both reduced (P<0.01), while polyphenol oxidase activity increased (P<0.01) and other enzymes' activities did not change significantly. As the time increased, the numbers of microorganisms and the activities of enzymes in saline-alkali soil increased significantly (P<0.01). The treatment A3B1 (straw dosage of 60 000 kg/hm2, burying depth of 10 cm) reached the highest activity for 6 kinds of enzymes and the highest yield of 1914 kg/hm2. The treatment A3B1 was the optimum of all treatments. Corn straw as the resource with advantage can be used for improving saline-alkali soil, which is of great significance to the protection of the ecological environment, the expansion of the grain growth and the revitalization of the rural economy in Tongliao City.