凋落物对典型草原植被及土壤水分的影响
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摘要
典型草原是内蒙古草原重要的组成部分,对内蒙古农牧业的发展有重要的作用。凋落物是草地的重要组成部分,并且是草地健康的重要指标。本文探讨了凋落物数量对植物群落组成、地上生物量数量特征以及其对土壤水分及渗透的影响,为凋落物在维持草原生态系统稳定性、草地资源持续发展重要性及草地科学管理和利用提供基础。
实验是在中国科学院内蒙古草原生态系统定位站退化样地进行的。于2002年秋季和2005年春季分别在退化样地做了凋落物添加和移除处理。试验设置3个处理,分别为重度添加(H)、中度添加(M)、重度移除(H)、中度移除(M)以及没有任何处理的对照(C)。在添加和移除处理后每年的生长旺季进行地上植被调查,包括地上生物量以及各个植物种的分种生物量,并在生长季内按月进行土壤水分含量测定。
实验结果表明:
1、不同季节的凋落物添加或移除对草地生产力有不同的影响。秋季进行的凋落物添加对草地生物量的影响大于春季添加凋落物的影响。适当的凋落物添加有利于草地生产力的增加。凋落物移除处理无论是春季还是秋季,对草地生产力均没有影响。
2、典型草原植被群落各不同功能群对凋落物添加和移除有不同的响应。其中多年生杂类草和一二年生植物对凋落物表现较为敏感。同时,多年生杂类草和丛生型禾草存在这生态补偿作用,有利于草原生态系统的稳定。
3、凋落物不同季节的添加或移除对土壤渗透率的影响不同。春季和秋季的凋落物添加对土壤渗透率的影响均未达到显著水平。秋季的凋落物中度移除后,土壤渗透率达到最大,显著高于对照区(P<0.05)。故保留适量的凋落物对土壤渗透率有积极的促进作用。
4、土壤水分受凋落物影响较大,但通常土壤水分之间的差异在处理后的第二年开始表现出来(P<0.05)。凋落物的添加有利于保持土壤水分;而凋落物移除加大了土壤水分的散失。导致土壤含水量下降。
Grassland ecosystem is one of the important types in terrestrial ecosystem; typical grassland is the important part of Inner Mongolia grassland which plays a key role in the development of agriculture and husbandry production. Litter is the significant component of typical grassland, and also an important indicator of grassland health. This paper probes into the effect of the amount of litter on vegetation community composition, characteristics of above-ground biomass and soil moisture and infiltration rate. The paper could be seen as the theoretical basis of the importance of litter in maintaining the stability of grassland system, rangeland resources sustainability and grassland scientific management and utilization.
The experiment was conducted in degraded site of Inner Mongolia Grassland Ecosystem Positioning Station, Chinese Academy of Sciences. In the fall of 2002 and 2005, the treatment of litter addition and removal were conducted respectively on degraded site. There are three treatments, including severe(H)and medium(M)litter addition and removal, and control(C).The above ground vegetation survey is implemented after addition and removal treatment in the growing season every year. The survey includes on above-ground biomass and biomass of each species. In the mean time, the determination of soil moisture content is conducted monthly in growing season. The experimental results show as follows:
1. Litter addition and removal in different season has different impact on grassland productivity. Litter added in fall has greater impact on grassland biomass than that in spring. Proper addition in litter is useful for increasing grassland productivity. Litter removal has no obvious influence on grassland productivity no matter in spring or fall.
2. The different functional groups in the typical grassland had the different response to litter addition or removal. Perennial forbs and annuals and biennials were sensitive to the litter change. Meanwhile, perennial forbs and bunch grass has ecological compensation effect which is good for the stability of the ecosystem.
3. The litter addition and removal in different seasons has various impacts on soil infiltration rate. The litter added in spring and fall had little influence on the soil infiltration rate. Medium litter removed in fall affected the soil infiltration; the highest value was 1.38mm/min, significantly higher than the control plot(P<0.05).
4. Soil moisture varied with the litter treatments but the significant difference of soil moisture appears in the following year after the treatments. The plot with litter covered had a large value of soil moisture (P<0.05). The removal of litter increased the loss of the water and decreased the soil moisture.
实验是在中国科学院内蒙古草原生态系统定位站退化样地进行的。于2002年秋季和2005年春季分别在退化样地做了凋落物添加和移除处理。试验设置3个处理,分别为重度添加(H)、中度添加(M)、重度移除(H)、中度移除(M)以及没有任何处理的对照(C)。在添加和移除处理后每年的生长旺季进行地上植被调查,包括地上生物量以及各个植物种的分种生物量,并在生长季内按月进行土壤水分含量测定。
实验结果表明:
1、不同季节的凋落物添加或移除对草地生产力有不同的影响。秋季进行的凋落物添加对草地生物量的影响大于春季添加凋落物的影响。适当的凋落物添加有利于草地生产力的增加。凋落物移除处理无论是春季还是秋季,对草地生产力均没有影响。
2、典型草原植被群落各不同功能群对凋落物添加和移除有不同的响应。其中多年生杂类草和一二年生植物对凋落物表现较为敏感。同时,多年生杂类草和丛生型禾草存在这生态补偿作用,有利于草原生态系统的稳定。
3、凋落物不同季节的添加或移除对土壤渗透率的影响不同。春季和秋季的凋落物添加对土壤渗透率的影响均未达到显著水平。秋季的凋落物中度移除后,土壤渗透率达到最大,显著高于对照区(P<0.05)。故保留适量的凋落物对土壤渗透率有积极的促进作用。
4、土壤水分受凋落物影响较大,但通常土壤水分之间的差异在处理后的第二年开始表现出来(P<0.05)。凋落物的添加有利于保持土壤水分;而凋落物移除加大了土壤水分的散失。导致土壤含水量下降。
Grassland ecosystem is one of the important types in terrestrial ecosystem; typical grassland is the important part of Inner Mongolia grassland which plays a key role in the development of agriculture and husbandry production. Litter is the significant component of typical grassland, and also an important indicator of grassland health. This paper probes into the effect of the amount of litter on vegetation community composition, characteristics of above-ground biomass and soil moisture and infiltration rate. The paper could be seen as the theoretical basis of the importance of litter in maintaining the stability of grassland system, rangeland resources sustainability and grassland scientific management and utilization.
The experiment was conducted in degraded site of Inner Mongolia Grassland Ecosystem Positioning Station, Chinese Academy of Sciences. In the fall of 2002 and 2005, the treatment of litter addition and removal were conducted respectively on degraded site. There are three treatments, including severe(H)and medium(M)litter addition and removal, and control(C).The above ground vegetation survey is implemented after addition and removal treatment in the growing season every year. The survey includes on above-ground biomass and biomass of each species. In the mean time, the determination of soil moisture content is conducted monthly in growing season. The experimental results show as follows:
1. Litter addition and removal in different season has different impact on grassland productivity. Litter added in fall has greater impact on grassland biomass than that in spring. Proper addition in litter is useful for increasing grassland productivity. Litter removal has no obvious influence on grassland productivity no matter in spring or fall.
2. The different functional groups in the typical grassland had the different response to litter addition or removal. Perennial forbs and annuals and biennials were sensitive to the litter change. Meanwhile, perennial forbs and bunch grass has ecological compensation effect which is good for the stability of the ecosystem.
3. The litter addition and removal in different seasons has various impacts on soil infiltration rate. The litter added in spring and fall had little influence on the soil infiltration rate. Medium litter removed in fall affected the soil infiltration; the highest value was 1.38mm/min, significantly higher than the control plot(P<0.05).
4. Soil moisture varied with the litter treatments but the significant difference of soil moisture appears in the following year after the treatments. The plot with litter covered had a large value of soil moisture (P<0.05). The removal of litter increased the loss of the water and decreased the soil moisture.
引文
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