不同利用方式对内蒙古小针茅荒漠草原土壤有机碳库及其结构的影响
发布时间：2018-11-15 19:00
【摘要】：土壤是陆地生态系统最大的碳库。土壤有机碳储量及其化学结构是全球碳循环研究的核心内容。本研究以内蒙古小针茅荒漠草原为研究对象,利用野外控制试验,研究了围封、开垦和不同放牧梯度等草原利用方式对土壤理化因子、土壤酶活性、土壤有机碳储量及其化学结构的影响。主要研究结果如下：1.不同利用方式对小针茅荒漠草原土壤理化因子和土壤酶活性的影响不同。同一土层,开垦和放牧与围封相比,小针茅荒漠草原土壤全氮和全磷含量、土壤脲酶、过氧化氢酶和碱性磷酸酶活性均呈不同程度的降低趋势,而土壤pH值呈升高趋势。随着放牧强度的增加,土壤全氮和全磷含量、土壤脲酶、碱性磷酸酶、过氧化氢酶活性逐渐降低,土壤pH值逐渐升高。同一处理,随着土层的加深,土壤全氮、全磷含量、土壤脲酶活性均表现为先增加后降低的趋势,在30～40 cm达到最大值。2.不同利用方式对小针茅荒漠草原土壤有机碳储量影响显著,与围封相比,开垦和放牧区土壤有机碳储量减少,具体表现为围封G0.50G0.94开垦G1.25,其中,G1.25和开垦区土壤有机碳储量显著(P0.05)低于围封区,随着放牧强度的增加土壤有机碳储量逐渐减少。同一土层,开垦和放牧与围封相比,土壤有机碳含量、有机碳密度有降低的趋势,随着放牧强度的增加,土壤有机碳含量、有机碳密度也逐渐减小。同一处理,随着土层的加深,土壤有机碳含量、有机碳密度先增加后降低,在30～40 cm土层达到最大值。3.不同利用方式对小针茅荒漠草原表层(0-20 cm)土壤活性有机碳含量影响显著。与围封相比,开垦和放牧降低了土壤水溶性有机碳、易氧化有机碳、微生物量碳含量,随着放牧强度的增加,土壤活性有机碳含量均逐渐降低。不同利用方式对小针茅荒漠草原土壤活性有机碳占总有机碳的比例影响不同。放牧和开垦与围封相比,表层土壤活性有机碳占总有机碳的比例降低。随着放牧强度的增加,土壤水溶性有机碳比例、易氧化有机碳比例、微生物量碳比例均表现为逐渐降低的趋势。土壤总有机碳、水溶性有机碳、易氧化有机碳、微生物量碳含量之间呈显著或极显著正相关关系,土壤有机碳及其活性组分之间相互连系、相互影响,可以通过活性有机碳的含量反应土壤有机碳的变化,进而反应土壤有机碳碳库的变化。4.围封、放牧和开垦对小针茅荒漠草原土壤有机碳结构的影响主要在数量上,有机碳化学组分没有发生变化,土壤有机碳以烷氧碳(34.86%～37.85%)为主,其次为烷基碳(26.05%～33.87%),再者为芳香碳(10.60%-17.69%)和羰基碳(14.57%～16.90%)。土壤腐殖化指数(烷基碳／烷氧碳)表现为围封区开垦区G0.50G0.94G1.25,芳香性表现为G1.25G0.94开垦区G0.50围封区。说明开垦和过度放牧使土壤有机碳稳定性降低,而围封休牧使土壤有机碳更趋稳定,在土壤固碳方面有一定的意义。
[Abstract]:Soil is the largest carbon pool in terrestrial ecosystems. Soil organic carbon storage and its chemical structure are the core of the global carbon cycle research. In this study, using the desert steppe of Stipa nipponii in Inner Mongolia as the research object, the physical and chemical factors and the activity of soil enzyme were studied by means of enclosure, reclamation and different gradients of grazing grassland. Effects of soil organic carbon storage and its chemical structure. The main results are as follows: 1. The effects of different utilization methods on soil physical and chemical factors and soil enzyme activity in Stipa nipponii desert steppe were different. In the same soil layer, the contents of total nitrogen and total phosphorus, the activities of urease, catalase and alkaline phosphatase in the soil of the desert steppe of Stipa pinelliforme showed a decreasing trend, but the pH value of the soil increased. With the increase of grazing intensity, the contents of total nitrogen and phosphorus, the activities of soil urease, alkaline phosphatase and catalase decreased gradually, and the pH value of soil gradually increased. In the same treatment, with the deepening of soil layer, the contents of total nitrogen, total phosphorus and soil urease activity increased first and then decreased, and reached the maximum value at 30 ~ 40 cm. The effects of different utilization methods on soil organic carbon storage in Stipa nipponii desert steppe were significant. Compared with enclosure, the soil organic carbon storage in reclamation and herding areas decreased, which was manifested by enclosed G0.50G0.94 reclamation G1.25. Soil organic carbon storage in G1.25 and reclamation areas was significantly lower than that in enclosed areas (P0.05), and gradually decreased with the increase of grazing intensity. In the same soil layer, the soil organic carbon content and the organic carbon density decreased compared with the enclosed soil. With the increase of grazing intensity, the organic carbon content and the organic carbon density of the soil gradually decreased. In the same treatment, with the deepening of soil layer, the content of organic carbon and the density of organic carbon increased first and then decreased, and reached the maximum value at 30 ~ 40 cm. The soil active organic carbon content in the surface layer (0-20 cm) of Stipa pinifera desert steppe was significantly affected by different utilization patterns. Compared with enclosure, reclamation and grazing decreased soil water-soluble organic carbon, easily oxidized organic carbon, microbial biomass carbon content, with the increase of grazing intensity, the soil active organic carbon content decreased gradually. The proportion of soil active organic carbon to total organic carbon was different in the desert steppe of Stipa punctatus. Compared with enclosed soil, the proportion of active organic carbon in surface soil was lower than that in grazing and reclamation. With the increase of grazing intensity, the ratio of water-soluble organic carbon, easily oxidized organic carbon and microbial biomass carbon decreased gradually. Soil total organic carbon, water-soluble organic carbon, easily oxidized organic carbon, microbial biomass carbon content showed significant or extremely significant positive correlation, soil organic carbon and its active components were connected and affected each other. The change of soil organic carbon and the change of soil organic carbon pool can be reflected by the content of active organic carbon. 4. The effects of enclosure, grazing and reclamation on the soil organic carbon structure of Stipa pinellifordii desert steppe were mainly in quantity, but the organic carbon chemical components did not change, and alkoxy carbon (34.86% 37.85%) was the main organic carbon in soil. Alkyl carbon (26.05%), aromatic carbon (10.60-17.69%) and carbonyl carbon (14.57C 16.90%). The humification index of soil (alkyl carbon / alkoxy carbon) was G0.50G0.94G1.25 and the aromaticity was G0.50G0.94G1.25. The results showed that reclamation and overgrazing decreased the stability of soil organic carbon, but closed and closed grazing made soil organic carbon more stable, which had a certain significance in soil carbon sequestration.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S812.2
[Abstract]:Soil is the largest carbon pool in terrestrial ecosystems. Soil organic carbon storage and its chemical structure are the core of the global carbon cycle research. In this study, using the desert steppe of Stipa nipponii in Inner Mongolia as the research object, the physical and chemical factors and the activity of soil enzyme were studied by means of enclosure, reclamation and different gradients of grazing grassland. Effects of soil organic carbon storage and its chemical structure. The main results are as follows: 1. The effects of different utilization methods on soil physical and chemical factors and soil enzyme activity in Stipa nipponii desert steppe were different. In the same soil layer, the contents of total nitrogen and total phosphorus, the activities of urease, catalase and alkaline phosphatase in the soil of the desert steppe of Stipa pinelliforme showed a decreasing trend, but the pH value of the soil increased. With the increase of grazing intensity, the contents of total nitrogen and phosphorus, the activities of soil urease, alkaline phosphatase and catalase decreased gradually, and the pH value of soil gradually increased. In the same treatment, with the deepening of soil layer, the contents of total nitrogen, total phosphorus and soil urease activity increased first and then decreased, and reached the maximum value at 30 ~ 40 cm. The effects of different utilization methods on soil organic carbon storage in Stipa nipponii desert steppe were significant. Compared with enclosure, the soil organic carbon storage in reclamation and herding areas decreased, which was manifested by enclosed G0.50G0.94 reclamation G1.25. Soil organic carbon storage in G1.25 and reclamation areas was significantly lower than that in enclosed areas (P0.05), and gradually decreased with the increase of grazing intensity. In the same soil layer, the soil organic carbon content and the organic carbon density decreased compared with the enclosed soil. With the increase of grazing intensity, the organic carbon content and the organic carbon density of the soil gradually decreased. In the same treatment, with the deepening of soil layer, the content of organic carbon and the density of organic carbon increased first and then decreased, and reached the maximum value at 30 ~ 40 cm. The soil active organic carbon content in the surface layer (0-20 cm) of Stipa pinifera desert steppe was significantly affected by different utilization patterns. Compared with enclosure, reclamation and grazing decreased soil water-soluble organic carbon, easily oxidized organic carbon, microbial biomass carbon content, with the increase of grazing intensity, the soil active organic carbon content decreased gradually. The proportion of soil active organic carbon to total organic carbon was different in the desert steppe of Stipa punctatus. Compared with enclosed soil, the proportion of active organic carbon in surface soil was lower than that in grazing and reclamation. With the increase of grazing intensity, the ratio of water-soluble organic carbon, easily oxidized organic carbon and microbial biomass carbon decreased gradually. Soil total organic carbon, water-soluble organic carbon, easily oxidized organic carbon, microbial biomass carbon content showed significant or extremely significant positive correlation, soil organic carbon and its active components were connected and affected each other. The change of soil organic carbon and the change of soil organic carbon pool can be reflected by the content of active organic carbon. 4. The effects of enclosure, grazing and reclamation on the soil organic carbon structure of Stipa pinellifordii desert steppe were mainly in quantity, but the organic carbon chemical components did not change, and alkoxy carbon (34.86% 37.85%) was the main organic carbon in soil. Alkyl carbon (26.05%), aromatic carbon (10.60-17.69%) and carbonyl carbon (14.57C 16.90%). The humification index of soil (alkyl carbon / alkoxy carbon) was G0.50G0.94G1.25 and the aromaticity was G0.50G0.94G1.25. The results showed that reclamation and overgrazing decreased the stability of soil organic carbon, but closed and closed grazing made soil organic carbon more stable, which had a certain significance in soil carbon sequestration.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S812.2
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