Management Options for Sustainable Land-Use of Inner Mongolia Typical Steppe: Lessons from a Comprehensive N Balance
- Publication Type
- Contribution to conference
- Authors
- Giese, M., Gao, Y., Asch, F., Brueck, H.
- Year of publication
- 2012
- Published in
- Resilience of agricultural systems against crises
- Editor
- Tielkes, E.
- Pubisher
- DITSL GmbH , Witzenhausen
- Page (from - to)
- 223
- Conference name
- Tropentag 2012
- Conference location
- Göttingen / Kassel
Inner Mongolian semi-arid grasslands are substantially affected by land degradationas a consequence of excessive overgrazing during the last decades. Nitrogen (N) isconsidered as a key element for ecosystem functions and therefore of fundamentalimportance to maintain forage production.N pathways of Chinese typical steppe were quantified at sites representing differentland-use practices including heavy grazing (HG) and haymaking.Results showed that grassland NPP requires 3–7 g N m−2yr−1, which is mainlyprovided by N mineralisation from the large soil organic matter pool. Our N balancesindicated that HG must be considered as N source with annual total net losses ofup to 1.7 g N m−2, mainly due to dust emissions and excrement export, the latterresulting from keeping sheep in folds overnight. Soil N mining by HG was indicatedby reduced pool sizes of both topsoil organic N, and above- and belowground biomassN. Haymaking contributed to substantial annual N losses (up to 1.4 g N m−2), but siteswere not affected by wind erosion and thus balanced with regard to N gains and losses.Management options in terms of a sustainable N balance could include sheep excre-ments redistribution to grazing areas with a potential to decrease up to 70 % of annualN loss related to animal feed intake. N losses due to export of live weight and woolwere relatively small and could be sustainable as soon as stocking rates are reduced toa level at which remaining biomass prevents wind erosion. The establishment of hay-making sites ameliorated by e.g. the cultivation of legumes may improve regional Nbalances. Small amounts of mineral N fertiliser can further contribute to a sustainableland-use with regard to the N balance and forage production. Most N-related pro-cesses were more intensive in seasons of higher water availability indicating complexinteractions between land-use intensity and climate variability.Land use practice (e.g.pastoralists in context of socio-economic systems) will be in-creasingly important for the management of N dynamics in Chinese typical steppeand, therefore, must be considered as a key component to maintain and optimiseecosystem services