Influences of different land use management on net primary productivity and belowground carbon allocation in a semi-arid Inner Mongolia Steppe
From our three years’ results, we reached the following conclusions about Inner Mongolia grassland: (1) rainfall variability and grazing control productivity and herbivory in an interactive manner; (2) mean annual precipitation is not always the most important factor determining the quantity of net production; distribution of precipitation and soil nutrient availability (e. g. N) can also significantly influence productivity; (3) heavy grazing leads to significant declines in ANPP, BNPP and litter biomass, no compensatory and overcompensatory growth was observed; (4) heavy grazing that lead to a removal of more than 50% of ANPP in relative normal years and even 70% under dry climatic conditions, is very detrimental to sustainability and maintenance of grassland. Risk of degradation is enhanced by prolonged drought; (5) 50-70% of carbon gain was allocated to root system; and (6) Restoration measures of degraded grassland in this steppe ecosystem can include the application of small amounts of N fertiliser, especially in years of medium to high rainfall.
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