Study On The Hoof Pressure And Trampling Intensity Of Yaks And Tibetan Sheep In Tianzhu Alpine Meadow

The effect of grazing livestock on grassland including ingestion, excretion and trampling. But relative to the ingestion and excretion, livestock trampling not only exist the entire grazing period, it also is the main cause of grassland degradation. In order to determining hoof pressure and trample equivalent unit of yak and Tibetan sheep, the body weight and trample area of 1~5 years of yaks and 1~3 years of Tibetan sheep were measured; trample steps of yak and Tibetan sheep under different grazing intensity were observed in alpine meadow of Tianzhu County, Gansu province. The results were as follows.1.The body weight and trample area of yak and Tibetan sheep increased with age increasing, and its growth rate substantially showed the treand of increase rapidly and then slowly. From the middle of October to the following year in late April, weight loss of yak ranged from 15% to 30%, while Tibetan sheep ranged from 10% to 20%. Trample area of the forehoof and hind hoof is substantially the same size. At the age from 1 to 4, the hoof pressure of yak is increased with the age increasing, while at the age of 5, the hoof pressure of yak decreased. At the age from 1 to 3, the hoof pressure of Tibetan sheep gradually increased with the age increasing.2.The local 4 years yak was trample 1 times equivalent to 2.6 sheep trample in Tianzhu, 2 years Tibetan sheep was trample 1 times equivalent to 0.8 sheep trample. Tan sheep each walking 1 step which produced four sheep trample, so the 4-year yak and 2-year Tibetan sheep were produced 10.4 and 3.2 sheep trample respectively.3.Rotational grazing in the summer, with the increasing of grazing time, ingestion trampling steps, trampling intensity, hoof-print numbers and trample area of yak and Tibetan sheep were gradually increased under the control area(CGA) and control livestock number(CLN) treatment, the walking trampling steps, trampling intensity, hoof-print numbers and trample area of yak was first increases and then decreases. While walking trampling steps, trampling intensity, hoof-print numbers and trample area of Tibetan sheep have differences under two treatments. Under the CGA treatment, the walking trampling steps, trampling intensity, hoof-print numbers and trample area of Tibetan sheep was first decreases and then increases under light grazing(LG) and moderate grazing(MG), it was first increases and then decreases under heavy grazing(HG). Under the CLN treatment, the walking trampling steps, trampling intensity, hoof-print numbers and trample area of Tibetan sheep showed a trend of “firstly increases and then decreases”. The trampling trampling steps and intensity of yak were higher than Tibetan sheep under two treatments, hoof-print numbers of Tibetan sheep was higher than yak, the ingestion trample area of yak was higher than Tibetan sheep, while the walking trample area of yak was less than Tibetan sheep. The influence of CLN treatment for livestock trampling steps, intensity, hoof-print numbers and trample area were higher than CGA treatment.In the free grazing condition, the ingestion steps and trample intensity of yak and Tibetan sheep were increased with the increasing grazing time, the ingestion steps and trample intensity of yak was 2747.5 steps, the figures was 3441.3 steps on Tibetan sheep. While the walking steps and trample intensity of yak and Tibetan sheep showed a trend of “firstly increases and then decreases” and as the results of CLN treatment, the walking steps and intensity of yak was higher, Tibetan sheep showed a similar trend as yak.4.Under the same compaction, the unit trampling area of the yak and Tibetan sheep increased along with the increase of soil moisture, while the hoof pressure of the yak and Tibetan sheep decreased. Under the same soil moisture, the unit hoof area of the yak and Tibetan sheep decreased along with the increase of compaction, while the hoof pressure of the yak and Tibetan sheep increased.5.The simulated trampler was developed. Simulated trampler was used to study on response of grassland to simulate trampling, it can accurately simulate trampling of grazing livestock.