Effect Of Grazing Intensity On Desert Grassland And The Determination Of Appropriate Stocking Rate In Inner Mongolia Midland

Stocking rate is an important factor that influences the production of grass and livestock in grassland grazing ecosystem. It will produce a series of negative effects on the system, if the grassland has over-heavy or over-light stocking rate for a long time. For this reason, to determine a proper stocking rate according to the practical situation of grassland is very necessary for keeping the sustaining, healthy and steady development of grassland grazing ecosystem. The desert steppe in Inner Mongolia midland was selected as a research object in our study, and the pasture degraded in different degree was chosen at Siziwang Banner of Wulanchabu League in Inner Mongolia. According to the relationships between stocking rate, grassland range condition and annual even grass yield, the effects of grazing ecology and grazing management plan on the desert steppe in the local region were investigated. The conclusions can be mainly drawn as follows:(1)In the early grazing period of June, grass yields of different degraded pastures differed obviously. But with the most plants reviving and growing later, grass yield increased greatly during this period and the disturbance of grazing has a great effect on the different degraded pastures, the grass yields of different degraded pastures have no obvious difference in August. In September, the grass yield of the control pasture (having no grazing disturbance) went on increasing and was significantly higher than those of other 3 degraded pastures. The grass yields of other 3 degraded pastures had no significant difference, but all had a declining trend.(2) With the increasing of grazing intensity, 6 diversity indexes (MA, Pa, H', D. JP, EA) all showed a trend of declining firstly and increasing later. There were significant differences in diversity indexes between control grazing and heavy grazing pasture (P<0.05), but no significant difference in diversity indexes between light and moderate grazing (P>0.05).(3)Grassland range conditions of control grazing, light grazing, moderate grazing and heavy grazing were respectively excellence, good, fair and fair. And with the increasing of grazing intensity, the grassland range condition showed a declining trend.(4)In experimental areas, the numbers of Eleven kinds plants declined, taking cleistogenes songorica and Convolvulus ammannii Desr for examples. The quantities of four kinds of plants keeps no obviously change, taking Stipa breiflora and Artemsia frigida for examples. The numbers of five plants increased, taking Salsola collina Pall for example.(5)Stocking rates of control grazing, light grazing, moderate grazing and heavy grazing were respectively 0.78 sheep/ hm2, 0.43 sheep/ hm2, 0.38 sheep/ hm2 and 0.30 sheep/ hm2. With the increasing of grazing intensity, theoretic livestock carrying capacity of grassland declined.(6)Grassland range condition has significant correlation with livestock carrying capacity and annual even grass yield (p<0.05); The regress model between grassland range condition and livestock carrying capacity was"y = 32.059x-36.855"; And the regress model between grassland range condition and annual even grass yield was"y = 0.7129x-36.977".(7)Theoretic livestock carrying capacity of control grazing, light grazing, moderate grazing and heavy grazing respectively was 56 sheep, 240 sheep, 96 sheep, 120 sheep. 512 sheep could be fed at the same time in the whole experimental area.Furthermore, a rotational grazing project was designed according to the actual condition of the experimental area, but its rationality and practicality need to be verified in the further study.