滩羊轮牧对陇东典型草原生物土壤结皮及其下层土壤理化性质的影响

发布时间：2018-05-20 20:34

本文选题：放牧 + 生物土壤结皮　；参考：《兰州大学》2017年硕士论文

【摘要】：放牧是草地管理和利用的主要方式,划区轮牧是最重要的草地现代管理技术之一,生物土壤结皮在草原生态系统功能的完整性有重要作用。生物土壤结皮是由蓝藻、地衣、苔藓和其他微生物组成的复杂群落,它们生活在土壤表层或表层的最底层,是一个很薄的水平层。为此,以陇东黄土高原滩羊—典型草原轮牧系统为对象,研究放牧对生物土壤结皮的结构组成及其下层土壤理化性质的影响。主要结果如下:1.放牧强度对植物、生物土壤结皮分布的影响在不同放牧强度的样地中,2015年和2016年地衣结皮盖度分别达到27.51%-40.74%、37.82%-42.19%,显著显著高于植被、苔藓、裸地以及凋落物的盖度(P0.05),同时植被和生物结皮的盖度之间存在显著差异(P0.05)。2015年苔藓结皮的盖度在5.33羊/公顷时为14.64%,显著小于其他放牧率(P0.05),随放牧率的增加,2016年苔藓结皮的盖度逐渐下降,当放牧率最大为8.67羊/公顷时,苔藓结皮的盖度达到最小值(16.11%)显著小于0、2.67和5.33羊/公顷的苔藓盖度(P0.05);放牧结束后由于植被补偿生长,2015年、2016年2.67羊/公顷的植被盖度达到最大,分别为:33.14%、32.81%,显著高于0和8.67羊/公顷(P0.05),与5.33羊/公顷的植被盖度无显著差异(P005),0和5.33羊/公顷的植被盖度无显著差异(P0.05),但均显著高于8.67羊/公顷(P0.05)。2.放牧强度对生物土壤结皮叶绿素含量的影响。放牧强度对生物结皮叶绿素的含量产生影响,不同类型结皮的叶绿素变化趋势不同。随放牧率的增加,地衣结皮中叶绿素的含量呈先下降后上升的趋势,当放牧率为0羊/公顷时,其叶绿素含量为7.72 mg/g,显著高于2.67、5.33和8.67羊/公顷(P0.05),2.67羊/公顷放牧率下的地衣结皮叶绿素含量为5.24 mg/g,显著高于5.33羊/公顷,但显著低于8.67羊/公顷(P0.05);苔藓与地衣结皮的叶绿素含量变化趋势相反,随着放牧率的增加先增加后下降,表现为5.338.672.670,且各放牧之间差异显著(P0.05)。3.放牧强度对生物土壤结皮下层土壤水分含量的影响2015年和2016年的土壤水分含量均呈:苔藓结皮地衣结皮裸地,说明苔藓有利于干旱的黄土高原地区涵养水分,防止水土流,同时随着放牧率的增加土壤含水量均呈现先增加后降低的趋势,说明适度放牧有利于维持土壤中的含水量。4.放牧强度对生物土壤结皮下层土壤理化性质的影响轻度(适度)放牧有利于增加草地土壤碳的储存,重牧减少草地土壤有机碳;苔藓结皮有利于提高土壤下层土壤有机碳含量;生物结皮下层土壤总氮含量、硝态氮、铵态氮含量随着放牧率的增加而呈下降趋势,同一放牧率下,下层土壤三者含量总体为苔藓结皮地衣结皮裸地;不同放牧强度下,生物结皮下层土壤的速效磷含量均为苔藓结皮地衣结皮裸地,且各个结皮类型下层土壤的速效磷含量在放牧地中均随着放牧率的增加而下降。综上,适宜的放牧能够促进生物土壤结皮的生长发育,改善生物土壤结皮下层土壤理化性质。
[Abstract]:Grazing is the main way of grassland management and utilization. The grazing is one of the most important modern management techniques for grassland. The biological soil crust plays an important role in the integrity of the function of the grassland ecosystem. The biological soil crust is a complex community composed of cyanobacteria, lichen, moss and other microorganisms. They live on the surface or surface of the soil. The bottom layer is a very thin horizontal layer. Therefore, the effects of grazing on the structure composition and the physical and chemical properties of the lower layer soil are studied by the grazing system of the beach sheep - typical grassland in the Loess Plateau of Eastern Gansu Province. The main results are as follows: 1. the effects of grazing intensity on the distribution of plant and biological soil crust in different grazing intensities In 2015 and 2016, the crust cover of the lichen reached 27.51%-40.74%, 37.82%-42.19%, significantly higher than the vegetation, moss, bare land and the coverage of litter (P0.05), and there was a significant difference between the vegetation and the cover of the biological crust (P0.05) in.2015, the cover of moss crust was 14.64%, significantly less than that of 5.33 sheep / hectare. With the increase of grazing rate (P0.05), the coverage of moss crust decreased gradually with the increase of grazing rate in 2016. When the maximum grazing rate was 8.67 sheep / ha, the coverage of moss crust reached a minimum (16.11%) less than 0,2.67 and 5.33 sheep / ha of moss coverage (P0.05); after grazing, the vegetation was compensated for growth, 2015, and 2016 2.67 sheep / hectare planting. The maximum coverage was 33.14%, 32.81%, significantly higher than 0 and 8.67 sheep / ha (P0.05), and no significant difference (P005) with 5.33 sheep / hectare vegetation coverage (P005), and there was no significant difference between the vegetation coverage of 0 and 5.33 sheep / ha (P0.05), but significantly higher than that of the 8.67 sheep / hectare (P0.05).2. grazing intensity on the content of chlorophyll in the biological soil crust. The chlorophyll content of biological crust was influenced by grazing intensity. The chlorophyll content of different types of crust was different. With the increase of grazing rate, the content of chlorophyll in lichen crust decreased first and then increased. When the grazing rate was 0 sheep / ha, the chlorophyll content was 7.72 mg/g, significantly higher than that of 2.67,5.33 and 8.67 sheep / hectare (P0.05), 2. The chlorophyll content of the lichen crust under 67 sheep / hectare grazing rates was 5.24 mg/g, significantly higher than 5.33 sheep / ha, but significantly lower than 8.67 sheep / ha (P0.05). The trend of chlorophyll content in moss and lichen crust was the opposite, as the grazing rate increased first and then declined, showing 5.338.672.670, and the difference between each grazing was significant (P0.05).3.. The effect of grazing intensity on soil moisture content in the underlayer of biological soil was observed in 2015 and 2016. The soil moisture content in 2015 and 2016 showed the bare ground of lichen crust crust. It indicated that moss was beneficial to water conservation and prevention of water and soil flow in the arid loess plateau area, and the soil moisture content increased first and then decreased with the increase of grazing rate. It is suggested that moderate grazing is beneficial to maintaining the influence of.4. grazing intensity on the physical and chemical properties of soil underlayer soil in the soil slightly (moderate) grazing is beneficial to increase the storage of soil carbon in grassland, and to reduce the organic carbon of grassland soil by heavy grazing; moss crust is beneficial to the increase of soil organic carbon content in soil underlayer soil; The total nitrogen content, nitrate nitrogen and ammonium nitrogen content decreased with the increase of grazing rate. Under the same grazing rate, the total content of the three people in the lower soil was bare ground lichen crust. Under different grazing intensities, the available phosphorus content of the soil under the biological crust was bare ground of lichen crust crust, and the different crust types were lower soil. The content of available phosphorus in the soil decreases with the increase of grazing rate. To sum up, suitable grazing can promote the growth and development of biological soil crust and improve the physical and chemical properties of the soil under the crust of biological soil.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812.2

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