Effects of grazing and precipitation on herbage production, herbage nutritive value and performance of sheep in continental steppe P. Scho ¨ nbach*, H. Wan*, M. Gierus*, R. Loges*, K. Mu ¨ ller†, L. Lin†, A. Susenbeth† and F. Taube* *Institute of Crop Science and Plant Breeding, Grass and Forage Science ⁄ Organic Agriculture, Christian- Albrechts-University, and †Institute of Animal Nutrition and Physiology, Christian-Albrechts-University, Kiel, Germany Abstract The present study highlights the effects of sheep grazing and precipitation on herbage and animal performance in a grazed steppe of Inner Mongolia. Experimental data were collected during grazing periods of four consecu- tive years (2005–2008), and effects were analysed across a gradient of seven grazing intensities. Variation in annual precipitation, reflected by the effect of ‘year’, was the major factor affecting herbage; i.e., the pro- duction and nutritive value of herbage increased with increasing precipitation. Herbage parameters were also affected by grazing intensity, as herbage production (HP) and herbage nutritive yields decreased, while herbage nutritive values increased with increasing grazing intensity. The grazing-induced decrease in herbage nutritive yields suggests that decreases in HP offset the positive effect of grazing on the nutritive value. Liveweight gain (LWG) was predominantly affected by grazing intensity, as LWG per sheep and per ha decreased and increased, respectively, with increasing grazing intensity. However, responses varied among years: LWG per sheep was maximized by light grazing in the drought year and by moderate grazing the wet year. Our results showed that herbage shortage at high grazing intensities reduces LWG per sheep and thus diminishes responses in LWG per ha. Nevertheless, the highest grazing intensity provides highest animal production per ha in the short term; however, this is not sustainable in the mid- and long term because decreasing HP induces degradation processes. Based on our results, a reduction in grazing intensity that still provides 78% of the maximum LWG per ha meets the requirements of a sustainable grazing management. Keywords: grazing experiment, grazing intensity, grazing management, herbage quality, Mongolia, net primary production Introduction The Inner Mongolian grassland is part of the Eurasian steppe ecosystem and is widely used for livestock grazing, mainly by goats and sheep. Increasing demand for grazing land has resulted in both a reduction in the size of the grassland and the need for it to support more livestock. Since the 1960s, the increasing grazing pressure has led to a substantial reduction in soil cover, and this has initiated degradation processes throughout much of the Inner Mongolian grassland (Wang and Ripley, 1997). Today, most of this steppe ecosystem is overgrazed and shows severe signs of degradation (Ren et al., 2008). Grassland degradation not only affects ecosystem multifunctionality but also imperils the production goals of farmers. For example, overgrazing typically reduces herbage production (HP) (Patton et al., 2007; Scho ¨ nbach et al., 2009, 2011) and alters species composition (Wang, 2004; Liang et al., 2009), which may constrain performance of grazing livestock. Fur- thermore, grazing affects herbage nutritive value, either directly through defoliation (Scho ¨ nbach et al., 2009) or indirectly through changes in species composition (Zhang et al., 2004; Cao et al., 2011). While improved herbage nutritive value has been considered to be a short-term grazing response (Scho ¨ nbach et al., 2009), possible changes in species composition, such as a shift from high- to poor-quality herbage species, may also follow long-term overgrazing (Christensen et al., 2003; Correspondence to: P. Scho ¨ nbach, Institute of Crop Science and Plant Breeding, Grass and Forage Science ⁄ Organic Agriculture, Christian-Albrechts-University, Hermann- Rodewald-Str. 9, 24118 Kiel, Germany. E-mail: pschoenbach@email.uni-kiel.de Received 7 September 2011; revised 16 February 2012 doi: 10.1111/j.1365-2494.2012.00874.x Ó 2012 Blackwell Publishing Ltd. Grass and Forage Science 1 Grass and Forage Science The Journal of the British Grassland Society The Official Journal of the European Grassland Federation