【作者】 闫飞；

【导师】 王定勇；

【作者基本信息】 西南大学 ， 环境科学， 2010， 硕士

【摘要】 我国农作物秸秆资源丰富,秸秆资源用途广泛,但如果不能有效利用,反而会成为巨大的污染源。另一方面,我国沙质土壤面积分布较广,沙质土壤具有结构性差、保水蓄水力弱、抗旱力差、养分含量少、保肥力差、土温变化快等特性,不利于农作物的生长,大多数沙质土壤属于肥力较差的土壤。可见,改良沙质土壤,提高沙质土壤肥力,是提升沙质土壤生产力的重要举措之一。本研究以同时解决这两方面的问题为设计思路,以秸秆作为主材,配以聚丙烯酰胺（PAM）和膨润土等功能材料,研究与开发秸秆沙质土壤改良材料,通过分析不·同配方改良材料对土壤理化性质的影响与效应,获得最佳秸秆沙质土壤改良材料配方及工艺参数,为实现农业秸秆资源高效利用提供科技支撑。本试验选择小麦、玉米、水稻、油菜等大宗秸秆为研究对象,秸秆经粉碎后,分别设计添加不同量的PAM和膨润土,形成系列配方的小麦、玉米、水稻、油菜秸秆改良材料,再利用盆栽试验,在沙质土壤上施用不同量的秸秆改良材料,经过3个月的培养试验,分别于第10d、30d、60d和90d取样分析土壤pH、容重、孔隙度、有机质、腐殖质、阳离子交换量等理化指标,考察不同秸秆改良材料对沙质土壤理化性质的作用效应,并由此来选择秸秆改良材料的最佳配方组合。结果表明：所设定的各配方秸秆（小麦、玉米、水稻、油菜）改良材料对沙质土壤的理化性质均有较为明显的影响效应。1、秸秆（小麦秸秆、玉米秸秆、水稻秸秆、油菜秸秆）改良材料相同施加量,不同配方时,随着PAM量的增大,沙质土壤的pH并没有显著的影响。2、添加秸秆（小麦秸秆、玉米秸秆、水稻秸秆、油菜秸秆）改良材料在相同施加量,不同配方时,PAM施用剂量越大,土壤容重呈明显减小趋势,土壤孔隙度逐渐增大。所有处理中在PAM含量越高（30‰时）时容重明显最小。随土培时间的增长,沙土容重先减少后增加,在土培60d时效果最佳。添加小麦、玉米、水稻、油菜秸秆改良材料后,土壤容重明显低于对照,孔隙度明显高于对照,差异均达到极显著（P<0.01）,土壤容重分别较对照减少0.27g/cm3、0.26g/cm³、0.25g/cm³和0.22g/cm³。汉秸秆改良材料剂量为10g.kg^-1、PAM含量为30%。,十培60d时土样容重最小,土壤结构改良效果最佳。4种秸秆改良材料中,小麦秸秆改良材料对沙质土壤容重的改良效果最佳,玉米秸秆改良材料次之,再次是水稻、油菜。3、添加秸秆（小麦秸秆、玉米秸秆、水稻秸秆、油菜秸秆）改良材料在相同施加量,不同配方时,PAM施用剂量越大,土壤有机质越大。设定的所有处理中在PAM含封越高（30‰时）时有机质最大。添加秸秆改良材料后,土壤有机质明显高于对照,差异极显著（P<0.01）;随土培时间的增长,沙质土壤有机质先增加后减少,在土培60d时效果最仕。施入小麦、玉米、水稻、油菜秸秆改良材料的沙质土壤有机质含量在土培60d时最大,分别较对照提高31%、26%、25%和25%。当秸秆改良材料剂量为10g.kg^-1、PAM含量为30%o,土培60d时土壤有机质含量最高,土壤结构改良效果最佳。4种秸秆改良材料中,小麦秸秆改良材料对沙土有机质的改良效果最佳,玉米秸秆改良材料次之,再次是水稻、油菜。4、添加秸秆（小麦秸秆、玉米秸秆、水稻秸秆、油菜秸秆）改良材料在相同施加量,不同配方时,PAM施用剂量越大,土壤腐殖质越大。所有处理中在PAM含量越高（30‰时）：时腐殖质最大。.添加秸秆改良材料后,土壤腐殖质明显高于对照,差异极显著（P<0.01）；随土培时间的增长,,沙质土壤腐殖质先增加后减少,在土培60d时效果最佳。施入小麦、玉米、水稻和油菜秸秆改良材料的沙质土壤腐殖质含量在土培60d后,分别较对照提高55%、39%、34%和32%。当秸秆改良材料剂量为10g.kg^-1、PAM含量为30‰，土培60d时土壤腐殖质含量最高,土壤结构改良效果最佳。4种秸秆改良材料中,小麦秸秆改良材料对沙土腐殖质的改良效果最佳,玉米秸秆改良材料次之,再次是水稻、油菜。5、添加秸秆（小麦秸秆、玉米秸秆、水稻秸秆、油菜秸秆）改良材料在相同施加量,不同配方时,PAM施用剂量越大,土壤阳离子交换量越大。所有处理中在PAM含量越高（30.‰时）时阳离子交换量最大。添加秸秆改良材料后,土壤阳离子交换量明显高于对照,.差异极显著（P<0.01）;随土培时间的增长,沙质土壤阳离子交换量先增加后减少,在土培60d时效果最佳。不同秸秆（玉米、小麦、水稻、油菜）改良材料施入沙质土壤60d后,即离子交换量分别较对照提高51%、33%、32%和31%。当秸秆改良材料剂量为10g.kg^-1、PAM含量为30‰,土培60d时土壤,阳离子交换量（CEC）最高,土壤结构改良效果最佳。4种秸秆改良材料中,小麦秸秆改良材料对沙土土壤阳离子交换量（CEC）的改良效果最佳,玉米秸秆改良材料次之,再次是水稻、油菜。更多还原

【Abstract】 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.更多还原