宋雪莲 丁磊磊 马茹菲

摘要 過度放牧是贵州喀斯特人工草地退化主要人为驱动力之一。研究贵州喀斯特人工草地放牧管理策略，对贵州人工草地的可持续发展有重要指导意义。本研究结合无人机技术对草地植被盖度进行调查，比较不同放牧强度对植被盖度、地上生物量、植被地上部碳氮含量的影响和相同模拟放牧强度对不同混播草地植被盖度、生物量、植被地上部碳氮含量的影响，分析地上生物量、植被地上部碳氮含量与盖度的相关性。结果表明，轻度放牧下，植被盖度、地上生物量鲜重、地上生物量干重和植被地上部碳氮比分别比重度放牧显著升高了16.4%、302.4%、292.5%和132.1%（p<0.01），植被地上部氮含量显著降低了58.2%（p<0.01），放牧强度对植被地上部碳含量影响不显著（p>0.01）；在相同模拟放牧强度干扰下，混播组合对植被盖度、地上生物量（鲜重和干重）、植被地上部碳、氮含量和碳氮比的影响均不显著（p>0.01）。相比于相同植被类型模式下的混播组合，草地盖度和地上生物量等的响应更受制于放牧强度调控，这进一步揭示，目前放牧强度下，贵州本地人工草地需要采取更低放牧强度的管理策略。不同放牧强度下，地上生物量、植被地上氮含量与植被盖度的相关性较好，结合无人机航拍图片，可为家庭牧场地上生物量和氮含量的无损、快速监测提供可行的途径。

关键词 放牧强度；植被盖度；生物量；碳氮含量；无人机技术；贵州省

中图分类号 S812 文献标识码 A 文章编号 1007-5739（2018）19-0255-07

Abstract Overgrazing is one of the most important human driving force to Guizhou karst artificial grassland degradation.The research on Guizhou karst artificial grassland grazing management strategyhas important guiding significance to the sustainable development of artificial pasture in Guizhou. Using unmanned aerial vehicle（UAV）technology to investigate vegetation coverage，this research compared the effects of the different grazing intensities on the vegetation coverage，aboveground biomass，aboveground carbon and nitrogen content，and also compared the effects of different mixed sowing combinations on the vegetation coverage，aboveground biomass，aboveground carbon and nitrogen content under the same simulated grazing intensity.The correlation of the aboveground vegetation，aboveground biomass，carbon and nitrogen content with vegetation coverage were also analyzed，respectively.The results showed that compared with heavy grazing，the vegetation coverage，aboveground biomass fresh weight，aboveground biomass dry weight and aboveground C∶N under light grazing significantly increased by 16.4%，302.4%，292.5% and 132.1%（p<0.01），respectively；the aboveground nitrogen content decreased significantly by 58.2%（p<0.01）.The impacts of grazing intensities on aboveground carbon content were not significant（p>0.01）.Under the same simulated grazing intensities，different mixed sowing combinations had no significant effect on aboveground biomass（fresh weight and dry weight），abovegr-ound carbon and nitrogen content and aboveground C∶N（p>0.01）.Compared with mixed seeding combinations，which vegetation type were same，response of vegetation coverage，aboveground biomass，etc.，were more limited by grazing intensity，which further suggested that lower grazing intensity management strategy in Guizhou local artificial grassland is needed.Under different grazing intensities，the aboveground biomass，aboveground nitrogen content had good correlation with vegetation coverage，which could provide a feasible way to monitor aboveground biomass and aboveground nitrogen content for family ranch combined with the UAV images.

Key words grazing intensity；vegetation coverage；biomass；carbon and nitrogen content；unmanned aerial vehicle（UAV）technology；Guizhou Province

喀斯特石漠化是我国西南喀斯特环境问题的热点之一，贵州省喀斯特面积达12.66万km2，占贵州省国土面积的71.89%[1]。石……