【作者】 李爱宗；

【导师】 张仁陟；

【作者基本信息】 甘肃农业大学 ， 植物营养学， 2007， 硕士

【摘要】 本文对甘肃中部干旱农业区的土壤水稳性团聚体的粒径分布、土壤有机碳含量、团聚体有机碳含量及其活性有机碳含量进行了系统的研究,从两方面说明耕作方式对土壤团聚体稳定性及其碳库的影响,一是进行保护性耕作后土壤团聚体稳定性提高的机制及其评价;二是保护性耕作对土壤碳库的作用,计算碳库管理指数。得出主要结果如下:1耕作方式对土壤有机碳库的影响免耕+秸秆覆盖(NTS)、传统耕作+秸秆覆盖(TS)、免耕(NT)处理有机碳含量较传统耕作(T)处理增加,其中秸秆覆盖更有利于土壤有机碳的形成。小麦/豌豆/小麦(W/P/W)轮作下NTS、TS、NT处理土壤有机碳含量与T处理相比,NTS处理提高了4.64%,TS处理提高了3.78%,NT处理提高了2.19%;豌豆/小麦/豌豆(P/W/P)轮作下TS、NTS、NT处理土壤有机碳含量与T处理相比,NTS处理提高了8.91%,TS处理提高了14.16%,NT处理提高了4.34%。NTS、TS和NT处理土壤微生物量碳含量均高于T处理,NTS、TS和NT有利于提高土壤微生物量碳含量的增加。W/P/W轮作下NTS、TS、NT处理土壤微生物量碳含量与T处理相比,NTS处理提高了69.67%,TS处理提高了48.14%,NT处理提高了33.22%;P/W/P轮作下NTS、TS、NT处理土壤微生物量碳含量与T处理相比,NTS处理提高了75.57%,TS处理提高了45.57%,NT处理提高了36.42%。2耕作方式对土壤水稳定性团聚体的影响NTS、TS、NT对土壤团聚体的改变都有积极的作用,NTS、NT、TS有利于>0.25mm水稳定性团聚体的形成,其中秸秆覆盖效应更明显。两种轮作下NTS、NT和TS处理>0.25mm水稳定性团聚体含量较T处理高。土壤团聚体平均重量直径NT、NTS、TS处理大于T处理。各处理0～5cm土层中>0.25mm水稳定团聚体含量明显高于5～10cm和10～30cm土层。3耕作方式对土壤团聚体有机碳的影响土壤团聚体稳定性随着有机碳含量的增加而增加,土壤结构稳定性也随着土壤有机碳含量的增加而提高。两种轮作下NT、TS、NTS处理土壤团聚体有机碳含量高于T处理,并达到显著性差异。不同处理下团聚体有机碳含量随着土层的增加而递减,表现出0～5cm土壤团聚体有机碳含量高于5～10cm,高于10～30cm。4耕作方式对土壤活性有机碳和碳库管理指数的影响NTS、NT、TS处理活性有机碳含量比T处理高。NT、NTS、TS处理都有利于土壤活性有机碳含量的提高,有助于土壤肥力的提高,其中NTS、TS处理最为明显。另外,NTS、NT、TS处理有利于土壤碳库管理指数提高,其中秸秆覆盖是碳库管理指数提高的直接原因。`更多还原

【Abstract】 Mankind processed different tillages and optimized soil structure according to the theory of systems engineering and ecology-economics in the central area of Loess Plateau of China, which not only controlled the loss of soil water and improved soil environment, but also increased crop income and soil structure stability. Conservation tillage is not only the factor that affects soil development, but one of important ways to improve soil the physical and chemical properties and crop yields in aridity agriculture area of loess plateau. We determined the soil organic carbon、distribution of soil water-aggregates、organic carbon of aggregates and active organic carbon under different tillage ways in the central area of Gansu. The purpose of this article was studying the effects of the stability of soil aggregate and the pool of the organic carbon, which may be gained from two factors, one was to know the reason of stability of soil aggregate and its appraising, the other was to study the effects of conservation tillage on the pool of carbon. The main conclusions were as fellows:1 Effects of tillage methods on soil organic carbon poolsCompared with Conventional tillage with no straw, No-till with straw cover,Conventional tillage with straw incorporated and No-till with no straw cover all increased soil organic carbon contents under two kinds rotation sequence, but No-till with straw cover to be more advantageous to improving the soil organic carbon.Under wheat/pea/wheat (W/P/W) rotation sequence, compared with Conventional tillage with no straw, No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover increased soil organic carbon contents by 4.64%,3.78% and 2.19% respectively. Under pea/wheat/ pe(aP/W/P)rotation sequence, compared with Conventional tillage with no straw, No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover increased soil organic carbon contents by 4.34%,14.16% and 8.91% respectively.Compared with Conventional tillage with no straw, No-till with straw cover,Conventional tillage with straw incorporated and No-till with no straw cover all increased contents of microbial biomass carbon of soil under two kinds rotation sequence, but No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover to be more advantageous to developing the content of microbial biomass carbon of soil. Under wheat/pea/wheat(W/P/W)rotation sequence, compared with Conventional tillage with no straw, No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover increased contents of microbial biomass carbon of soil by 69.67%,48.14% and 33.22% respectively. Under pea/wheat/ pea(P/W/P)rotation sequence, compared with Conventional tillage with no straw, No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover increased contents of microbial biomass carbon of soil by75.57%, 45.57% and 36.42% respectively.2 Effects of tillage methods on water-aggregate stabilityCompared with Conventional tillage with no straw, No-till with straw cover,Conventional tillage with straw incorporated and No-till with no straw cover all increased contents of >0.25mm soil water-aggregates and mean weight diameter(MWD), and contents of >0.25mm soil water-aggregates of 0-5cm layer has significantly increased the content of >0.25mm soil water- stable aggregates of 5-10cm and 10-30cm layer in every treatment. The analysis result showed that No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover to be more advantageous to developing >0.25mm soil water-stable aggregates, and >0.25mm soil water-stable aggregates are highly positive correlated with mean weight diameter.3 Effects of tillage methods on soil organic carbon of aggregatesUnder wheat//pea/wheat(W/P/W)and pea/wheat/pea(P/W/P)rotation sequence, Compared with Conventional tillage with no straw, No-till with straw cover,Conventional tillage with straw incorporated and No-till with no straw cover increased organic carbon contents of soil aggregates and significant difference. In four treatments, the organic carbon content of soil aggregates in 0-5cm layer was higher than 5-10cm and 10-30cm layer. The result showed that the stability of aggregates was increased with content of organic carbon, so the stability of soil structure was also improved.4 Effects of tillage methods on active organic carbon and carbon pool management indexCompared with Conventional tillage with no straw, No-till with straw cover,Conventional tillage with straw incorporated and No-till with no straw cover improved the contents of soil active organic carbon under different tillage methods. The research results showed that No-till with straw cover, Conventional tillage with straw incorporated and No-till with no straw cover to be advantageous to developing the contents of soil active organic carbon. However, its can be also advantageous to increased carbon pool management index, especially the straw cover was important factor for increasing carbon pool management index.更多还原