Effects Of Straw Modified Material On The Physicochemical Properties Of Sandy Soil

Crop straw is rich in resources, extensive in use, but if not effectively used, it will become a huge source of pollution. On the other hand, the area of sandy soil is wide of distribution, sandy soil has characteristics of weak structure, weak water-retention, weak drought resistance, less nutrients, weak fertility preserving, and rapid changes in soil temperature, which goes against to. crops, and most of the sandy soil is of poor fertility. Therefore, to modified and improve the fertility of sandy soil is one of the most important measures to improve the productivity of sandy soil. In this study,, the two problems are solved together as the designed idea, straw is set as the main material, add to polyacrylamide (PAM) and bentonite functional, research and develop the modified materials, analyze different formulations of modified materials to achieve the best formulation and technical parameters, to supply technical support of the straw highly used.In this test, wheat, corn, rice and rape straw is selected as the research objects, after being crushed, add different amounts of PAM and bentonite, forming series formula of wheat, corn, rice and rape straw modified materials, then different amount of straw modified materials are applied with pot experiment, after 3 months of culture test, physical and chemical index such as pH, bulk density, porosity, organic matter, humus, cation exchange capacity are analyzed at 10 days,30 days, 60 days and 90 days. The action effect of different straw modified materials and soil physical and chemical properties are studied, in order to select the best formula of modified materials.1. The same amount of straw modified material (maize straw, wheat straw, rice straw, rape straw) was applied but different formulation, with the increasing amount of PAM the effect on pH was not significant.2. Straw (maize straw, wheat straw, rice straw, rape straw) applied in the same amount of modified materials, different formulations, with more amount of PAM, bulk density decreased while soil porosity increased. Of all the treatment, when the content of PAM is 30‰, the bulk density is minimum. With the increase time of soil culture, sand bulk density first decreased then increased, the best effect was on the 60^th day.After adding straw modified material, soil bulk density significantly lower than the control, the porosity was significantly higher than the control, the differences were extremely significant (P<0.01). Bulk density of sandy soil reached minimum on the 60^th day after adding sweat straw,corn straw,rice straw and rape straw, was lowered 0.27g/cm³,0.26g/cm³,0.25g/cm³ and 0.22g/cm³.When the straw materials was10g.kg^-1, the content of PAM was 30‰(for 10.3), bulk density of sandy soil reached minimum and the modified effect was best on the 60^th day. Among the four kinds of modified materials, the best one of improving the sandy soil bulk densiy is wheat straw, followed by maize straw, rice straw and rape straw.3. Straw (maize straw, wheat straw, rice straw, rape straw) applied in the same amount of modified materials, different formulations, with more amount of PAM, soil organic matter increased. Of all the treatment, when the content of PAM is30‰, the organic matter is maximal. After adding straw modified material, the organic matter was significantly higher than the control, the differences were extremely significant (P<0.01). With the increase time of soil culture, organic matter first increased then decreased, the best effect was on the 60^th:day. Organic matter of sandy soil reached maximal on the 60^th day after adding sweat straw,corn straw,rice straw and rape straw,was higher than control with 31%,26%,25% and 25%. When the straw materials was 10g.kg^-1,the content of PAM was 30‰(for 10.3), organic matter of sandy soil reached maximal and the modified effect was best on the 60^th day. Among the four kinds of modified materials, the best one of improving the sandy soil organic matter is wheat straw, followed by maize straw, rice straw and rape straw.4. Straw (maize straw, wheat straw, rice straw, rape straw) applied in the same amount of modified materials, different formulations, with more amount of PAM, soil humic substances increased. Of all the treatment, when the content of PAM is30‰, the humic substances is maximal. After adding straw modified material, the humic substances was significantly higher than the control, the differences were extremely significant (P<0.01). With the increase time of soil culture, humic substances first increased then decreased, the best effect was on the 60^th day. Humic substances of sandy soil reached maximal on the 60^th day after adding sweat straw,corn straw,rice straw and rape straw, was higher than control with 55%,39%,34% and 32%. When the straw materials was 10g.kg^-1 the content of PAM was 30%o (for 10.3), humic substances of sandy soil reached maximal and the modified effect was best on the 60^th day. Among the four kinds of modified materials, the best one of improving the sandy soil humic substances is wheat straw, followed by maize straw, rice straw and rape straw.5. Straw (maize straw, wheat straw, rice straw, rape straw) applied in the same amount of modified materials, different formulations, with more amount of PAM, soil cation exchange capacity increased. Of all the treatment, when the content of PAM is 30‰, the cation exchange capacity is maximal. After adding straw modified material, the cation exchange capacity was significantly higher than the control, the differences were extremely significant (P<0.01). With the increase time of soil culture, cation exchange capacity first increased then decreased, the best effect was on the 60^th day. Cation exchange capacity of sandy soil reached maximal on the 60^th day after adding sweat straw,corn straw,rice straw and rape straw was higher than control with 51%,33%,32% and 31%. When the straw materials was 10g.kg^-1, the content of PAM was 30‰(for 10.3), cation exchange capacity of sandy soil reached maximal and the modified effect was best on the 60^th day. Among the four kinds of modified materials, the best one of improving the sandy soil cation exchange capacity is wheat straw, followed by 'maize straw, rice straw and rape straw.