Location: Range Management ResearchTitle: Effects of stocking rate on the variability of peak standing crop in a desert steppe of Eurasia grassland Author
Submitted to: Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2013
Publication Date: 2/1/2014
Publication URL: http://handle.nal.usda.gov/10113/58880
Citation: Wang, Z., Jiao, S., Han, G., Zhao, M., Ding, H., Zhang, X., Wang, X., Ayers, E., Willms, W., Havstad, K.M., A, L., Liu, Y. 2014. Effects of stocking rate on the variability of peak standing crop in a desert steppe of Eurasia grassland. Environmental Management. 53:266-273. Interpretive Summary: Since 2002 our research unit in Las Cruces, NM has collaborated with the Inner Mongolia Agricultural University in Hohhot, China or shred research objectives regarding management of rangelands. Livestock grazing practices in Inner Mongolia, China have been hampered by a lack of quantitative, science-based information on proper stocking rates for key ecological sites. Our research unit ahs worked with our Chinese colleagues to design and implement experiments to identify proper stocking rates for sheep grazing desert grasslands of Northern China. In this experiment conducted over an 8-year period, we observed responses of vegetation to 3 different stocking rates for a 6-month grazing period from June through November. The heaviest stocking rate of about 1 ewe per acre for the 6 month season proved to be too heavy and caused reduction in amount of vegetation and changes in composition of vegetation. Stocking rates of less than 1 ewe per acre for the grazing system had minimal impacts on vegetation resources. Control of stock rates to levels deemed proper is currently the most important factor in halting rangeland degradation in northern China.
Technical Abstract: Proper grazing management practices can generate corresponding compensatory effects on plant community production, which may reduce inter-annual variability of productivity in some grassland ecosystems. However, it remains unclear how grazing influences plant community attributes and the variability of standing crop. We examined the effects of sheep grazing at four stocking rate treatments [control, 0 sheep ha-1 month-1; light (LG), 0.15 sheep ha-1 month-1; moderate (MG), 0.30 sheep ha-1 month-1; and heavy (HG), 0.45 sheep ha-1 month-1] on standing crop at the community level and partitioned by species and functional groups, in the desert steppe of Inner Mongolia, China. The treatments were arranged in a completely randomized block design over a 9-year period. Standing crop was measured every August from 2004 to 2012. Peak standing crop decreased (P\0.05) with increasing stocking rate; peak standing crop in the HG treatment decreased 40 % compared to the control. May–July precipitation explained at least 76 % of the variation in peak standing crop. MG and HG treatments resulted in a decrease (P\0.05) in shrubs, semi-shrubs, and perennials forbs, and an increase (P\0.05) in perennial bunchgrasses compared to the control. The coefficients of variation at plant functional group and species level in the LG and MG treatments were lower (P\0.05) than in the control and HG treatments. Peak standing crop variability of the control and HG community were greatest, which suggested that LG and MG have greater ecosystem stability.