Effect of Corn Straw-Bentonite-Polyethylene on Physical Properties of Sandy Soil

Abstract

In recent years, a variety of soil amendments came out and achieved certain results in the modification of desertification soil. However, most soil amendments belong to chemical product. They’re cost and produce secondary pollution easily. In order to further study on the measures to improve degeneration soil, make full use of renewable resources, and minimize secondary pollution, corn straw, bentonite and PAM were used simultaneously in the pot experiment to explore their synergic effect on the structure of sandy soil. In this test, corn straw is selected as the research objects. Different amounts of straw modified materials are applied in the pot experiment. Physical properties such as pH, bulk density, and aggregates were analyzed at 10 days, 30 days, 60 days and 90 days. Results showed that under the condition of different additions and doses of straw modified material, with the increase of PAM, the straw modified material did not have significant influence on pH value of sandy soils. Bulk density of the sandy soil decreased under the effect of the straw modified material. The higher the doses, or the more the content of PAM (but still<2%), the more apparently the bulk density decreased. With the increase of time, bulk density of the soil first increased and then decreased, reaching minimum at 60 days. The content of 1~5 mm aggregate increased obviously at 90 days with the addition of modified material, which was 2.12 times of control value. With the increase of content of PAM (<2%), the content of 1~5 mm aggregate increased gradually. When the content of PAM continued to increase (reaching 3%), the content of 1~5 mm aggregate decreased instead. Effect of straw modified material on sandy soil was optimum under the condition of corn straw, bentonite (albany grease, 200 item) and PAM (anionic poluacrylamides, 1.0×107 daltons, and solution 30%) 900:100:20, 10g/5kg for 60 days of pot experiment.