阿坝牧区草地不同利用方式与程度对植被碳含量的影响

Impact of different use patterns and degrees of grassland use on vegetation carbon storage in the Aba grassland pastoral area

为探讨不同利用方式与程度对草地植被碳含量的影响，对阿坝牧区不同利用方式草地（封育天然割草地、人工栽培、放牧草地）和植物生长季不同利用程度草地植被的地上部分、地下根系和枯落物的碳含量进行调研。结果表明，1）草地地上植被碳含量在不同利用方式上表现为封育天然割草地、冬春放牧草地和人工栽培草地显著高于夏秋放牧草地（P〈0．05）；生长季不同利用程度上冬春和夏秋轻度放牧草地显著高于重度和中度放牧草地（P〈0．05）。2）草地枯落物碳含量在不同利用方式与程度上差异均不显著。3）从根系总碳含量来看，不同利用方式上夏秋放牧草地和封育天然割草地显著高于冬春放牧草地和人工栽培草地（P〈0．05）；生长季不同利用程度上夏秋中度和轻度放牧草地显著高于夏秋重度和冬春放牧草地（P〈0．05），且各种利用方式与程度草地地下根系总碳含量均从表层向下依次显著的递减（P〈0．05），o～10cm的根系碳含量占总量的65％以上，10～30cm各草地根系碳含量差异不显著（P〈0．05）。通过数量关系得出，草地植被碳含量在利用方式上表现为封育天然割草地（356．509g／m^2）〉冬春放牧草地（297．780g／m^2）〉人工栽培草地（164．953g／m^2）〉夏秋放牧草地（137．577g／m^2），地上植被碳含量分别为地下根系碳含量的15．334，17．130，9．167和5．146倍；在生长季不同利用程度上表现为冬春放牧草地（297．780g／m^2）〉夏秋轻度放牧草地（217．002g／m^2）〉夏秋重度放牧草地（113．849g／m^2）〉夏秋中度放牧草地（81．882g／m^2），地上植被碳含量分别为地下根系碳含量的17．130，8．636，4．412和2．430倍。利用方式和放牧强度是影响草地植被碳含量的重要因素。

For studying the influence of different use patterns and degrees on the carbon storage of grassland vegetation in the Aba pastoral area, the ground vegetation, litter and underground biomass were measured in grasslands with different use patterns （fenced mown grassland, artificial grassland, winter and spring grazing meadowland and summer and autumn grazing pasture） and different degrees of use in the growing season （winter and spring graze meadowland, summer and autumn mild grazed land, summer and autumn moderate grazed pasture and summer and autumn severe grazed land）. 1） In terms of use pattern, the carbon storage of aboveground vegetation on the fenced mown grassland, winter and spring grazed meadowland and artificial grassland was significantly （P〈0.05） higher than those on the summer and autumn grazed pasture. In terms of degree of use in the growing season, winter and spring grazed meadowland and summer and autumn mild grazed land was significantly （P〈0.05） higher than summer and autumn severe grazed land and summer and autumn moderate grazed pasture. 2） Differences in the carbon storage of litter was not significant. 3） In use patterns, the total carbon storage of roots on the summer and autumn grazed pasture and fenced mowing grass land was significantly higher than those on the winter and spring grazed meadowland and artificial grassland. In degree of use in the growing season, summer and autumn moderate grazed pasture and summer and autumn mild grazed land was significantly higher than summer and autumn severe grazed land and winter and spring grazed meadowland. The carbon storage of roots significantly decreased downward from the surface. The car bon storage of roots from 0 to 10 cm was more than 65% of the total, while from 10 to 30 cm there was no significant difference. In terms of use pattern, the carbon storage of grassland vegetation appeared as fenced mown grassland （356. 509 g/m^2）〉winter and spring grazed meadowland （297. 780 g/m^2）〉artificial grassland （164. 953 g/m^2）〉summer and autumn grazed pasture （137. 577 g/m^2）, and the carbon storage of ground vegetation was 15. 334, 17. 130, 9. 167 and 5. 146 times respectively of the carbon storage of underground roots. In terms of use in the growing season, winter and spring grazed meadowland （297. 780 g/m^2）〉summer and autumn mild grazed land （217. 002 g/m^2）〉summer and autumn severe grazed land （113. 849 g/m^2） 〉summer and autumn moderate grazed pasture （81. 882 g/m^2）, and the carbon storage of ground vegetation was 12.1304, 8. 636, 4. 412 and 2. 430 times respectively of the carbon storage of underground roots. The results showed that use pattern and grazing intensity are important factors influencing carbon storage of grassland veg etation.