more than 85%. Li reports that biomass increased to 4500–6750 kg per hectare, and in some cases to 12,750 kg per hectare. Aeroseeding also increased the biological diversity of this vegetation cover from a range of 1–24 species before seeding to 8–40 species afterward. The main species adopted for aeroseeding were Caragana microphylla, Astragalus adsurgens, Hedysarum fruitcosum, Lespedeza sp., and Agropyron cristatum. These species stabilize the sand and serve as forage. Li concludes that approximately 30% of the semidrift sandy land and gently sloping drift sandy land are suitable for aeroseeding and urges the government to invest funds in aeroseeding in the Horqin Sandland region.

Livestock Rotation Research on the potential for livestock rotation as a means of reducing the degradation of grasslands is underway at several locations in the forest steppe zone. Sheehy (1990) reports one example from the Ih Nur Pilot Demonstration Area, Balinyouqi [Bairin Right Banner] near Chifeng City, Inner Mongolia. The Ih Nur area was established in 1985 as a focus for modernizing pasture and livestock management. In 1985, it covered 6000 hectares (90,000 mu ) and provided forage for 13,561 sheep equivalent units (SEU). By 1987, livestock in the area had increased by 5.9% to 14,355 SEU. Measurement and comparison of standing crops available to livestock in the pilot area and within grazing exclosures were used to determine the productivity of the rangeland with and without grazing and the amount of vegetation being consumed by livestock during the growing season.

A four-pasture deferred rotation system has been developed for the Ih Nur area. In this system, the key species of grasses are crested wheatgrass (for the cool season), Baical needlegrass (for the warm season), and Cleistogenes (for the warm season). Key forbs are Lespedeza and wild alfalfa. Each of four pastures is deferred from grazing during a different season over a four year period. For example, in year 1, pasture A is rested during the winter season, pasture B during the spring season, pasture C during the summer season, and pasture D during the winter season. Each succeeding year, a different pasture is deferred during each season, so that after four years each pasture has been deferred in each season. In the fifth year, the deferment cycle begins again. Although the four-pasture system corresponds to the existing management units, Sheehy says that a three-pasture and a two-pasture system would also be applicable.

According to Sheehy, one of the major advantages of this grazing system is the simplicity of decision making by the herdsmen regarding numbers of animals. Using this system, the herdsmen do not have to decide on proper animal numbers or the correct stocking rate. Rather, they can continue to make traditional decisions about whose livestock, or how many livestock, can use nondeferred pastures in each grazing management unit. The only restriction is that no livestock use the deferred pasture during the season of deferment. Families or groups of families can rotate their herds within a single grazing management unit or combine all livestock of a particular type (e.g.,

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement