论文部分内容阅读
Sonora研究站做了为期4年的试验。旨在测定两个放牧系统对草地植被的影响。每个放牧系统中有7个牧场和1群家畜。放牧设计为短时期(SDG)(放牧7d,闭牧42d)和高强度、低频率(HILF)(放牧14d,闭牧84d)两个处理。两个处理的放牧率均为10.4hm~2/auy。结果表明:1.草地地上部分净初级产量(ANPP)年间相差较多,而在不同处理间没有差异。2.两个处理中草地植被成分在4年之后发生明显的变化。在SOG处理短草产量第1年占总ANPP45％,到第4年上升为74％;而在HILF处理短草地上部分产量第1年占总ANPP的44％,第4年上升为51％。中草的地上部分净产量在SDG处理从第一年占ANPP的3.8％上升到第4年的13.6％,而在HILF处理则中草产量由第1年的4.7％上升为第4年33.9％。由试验结果得出如下结论:在短草向中草的次生演替中,短时期放牧处理没有高强度、低频率放牧处理效果明显。
Sonora Research Station made a 4-year trial. The aim was to determine the effects of two grazing systems on grassland vegetation. There are seven pastures and one herd of livestock in each grazing system. The grazing was designed as two treatments: SDG (grazing 7d, closed grazing 42d) and high intensity, low frequency (HILF) (grazing 14d, closed grazing 84d). The grazing rates of both treatments were 10.4 hm ~ 2 / auy. The results showed that: 1. There was a significant difference in annual net primary yield (ANPP) between above and below grasslands, but no difference between treatments. 2. The grassland vegetation composition changed significantly after 4 years in both treatments. In the first year of SOG, short grass production accounted for 45% of the total ANPP and increased to 74% in the fourth year. In the first year, part of the production of short grass in the HILF accounted for 44% of the total ANPP and increased to 51% in the fourth year. The net above-ground net production of Chinese grass increased from 3.8% of ANPP in the first year to 13.6% of the fourth year in SDG, while that of middle grass increased from 4.7% in the first year to 33.9% in the fourth year under the HILF treatment . From the test results, we can draw the following conclusions: Among the secondary succession of short grass to middle grass, the grazing treatment in short period did not have high intensity and the effect of low frequency grazing was obvious.