摘要
以青海省8个地区为研究区,利用MODIS归一化植被指数产品、地面实测样方数据和统计资料,建立青海省天然草地资源产量估算模型以及各地区草畜平衡监测模型,对青海省各地区的天然草地产草量及超载状况进行分析。结果表明:①2007年全省天然草地产草量为12552.1×104t,其中以海北地区最高,占36.60%,最小的为西宁和海东地区,分别为1.40%和1.60%;②2007年全省天然草地超载最严重的是西宁、海东和海南,超载率均高于100%,未超载的地区是海北和海西;③考虑农业、林业等补饲因素后,计算得出海南地区超载最严重,超载率为181.30%;除海西和海北两地区外,其他地区的超载率相对于天然草地有所下降,但仍有较严重超载。因此,应当加大农业、林业等补饲,维持天然草地及地区畜牧业的有效、合理发展。
Grassland ecological systems play a fundamental role in the terrestrial system.Grassland degradation can lead to a series of environmental problems,such as soil erosion and sandstorm. Achieving dynamic grassland monitoring and performing evaluation of forage-animal production balances are of great importance to the implementation of grassland sustainable development.The authors evaluated forage-animal production balances over Qinghai Province,which is rich in grasslands and located in the eastern Qinghai-Tibet Plateau.The area of usable pasture areas ranks fourth in China,and the annual production of sheep and other livestock ranks fourth and fifth, respectively.In this study,observed grassland yield data were obtained from GPS.Continuous 16-days composites of Moderate-resolution Imaging Spectroradiometer（MODIS）-Normalized Difference Vegetation Index（NDVI）images of 500 m spatial resolution were acquired.Natural grassland yield estimation models and models for estimating theoretical livestock carrying capacity of 8 prefectures in Qinghai Province were established based on these data sources.Considering reality of seasonal use of natural grasslands in this region,the maximum livestock carrying capacity of natural grasslands were analyzed.Supplementary forage was calculated from by-products from farming and forest recorded in Qinghai Statistical Yearbook.In terms of actual livestock carrying capacity derived from statistical data,the carrying capacity of natural grasslands or supplementary forage and the actual number of livestock were compared.Results showed that the total natural grassland productivity was 125.521×106t in Qinghai in year 2007 and the grassland yield in Haibei Prefecture was largest,indicating a value of 45.9×106t.Haidong and Xining Prefectures had the least yield,being 1.95×106t and 1.73×106t,respectively.The largest livestock carrying capacity of natural grassland was found to be in Haibei Prefecture,being about 8.56× 106sheep units.The natural grassland carrying capacity of Haidong and Xining was smaller than other prefectures.Excluding supplementary forage,the overgrazing rates of natural grasslands in Xining,Haidong,and Hainan exceeded 100%.With considering the carrying capacity with the use of supplementary forage,overgrazing rates of 50%-100%were found in Xining,Haidong, Huangnan,and Yushu.A balance between livestock carrying capacity and actual number of livestock was shown in Haibei and Haixi Prefectures,with implying overgrazing rates of-32.2% and-29.7%,respectively.At the provincial level,without considering the carrying capacity with the use of supplementary forage,the overgrazing rate was found to be 53.85%,equivalent to 15.3× 106sheep units.When considering the supplementary forage,the overgrazing rate was 36.37%, about 11.7×106 sheep units.To that end,when the carrying capacity of natural grasslands or supplementary forage is compared with the actual number of livestock,the province tends to be overgrazed.
出处
《资源科学》
CSSCI
CSCD
北大核心
2012年第2期367-372,共6页
Resources Science
基金
国家“863”计划数字农业技术课题(编号:2006AA10Z241)
关键词
产草量
遥感监测
超载率
青海省
Grassland productivity
Remote sensing monitoring
Overloading rate
Qinghai Province
