Effect Of Different Grazing Ways On Soil Physical And Chemical Properties And Carbon Balance In Steppe Desert

Rational grazing is important for maintaining the ecological desert steppe and the healthy development of animal husbandry. The research set at the desert sttepe of Ningxia, in order to investigates the effects of different grazing ways on soil aggregates, particle composition and organic, plant net primary productivity, soil respiration flux and characteristics of grassland carbon balance, the results showed that:(1) Under the ungrazed(CK) and continue grazing(CG), two districts rotational grazing(TG), four districts rotational grazing(FG) and six districts rotational grazing(SG). The soil moisture was higher in FG and SG at5-15cm and25-40cm, the soil bulk density in CG was significantly higher than the other treatments at5-15cm (p<0.05). The soil bulk density and soil moisture content of other soil layers under different grazing ways were not significant (p>0.05). The soil water holding capacity in the depth of0-40cm showed that FG、SG and CK were higher than other treatments, but the total soil porosity, capillary porosity was not significant.(2) Soil particles in the experiment area consist of sand, accounting for about70%at the0-40cm soil layer. Rotational grazing methods had no effect on the composition of the soil particles. SG helps to maintain the stability of surface and deep desert grassland soil structure, TG helps to maintain soil stability at5-15cm.(3) FG pasture soil organic matter content in the10-40cm soil layer is higher than other treatments, SG and CK pasture got higher available potassium content at15-40cm. But the organic matter, total nitrogen,available potassium, available phosphorus, nitrogen hydrolysis were unsignificant in CK, CG, TG, FG and SG at0-40cm.(4) Under the entire grazing period, the standing crop showed a steady tendency at first then decreased. The aboveground biomass of CG and SG is higher than TG、FG and CK. The livestock feed intake and the plant growth yield at different rotational grazing cycle showed a different trend. CK got the highest amount of litter fall. All treatments were unsignificant on belowground biomass. The net primary productivity of CK、CG、TG、FG and SG were227.95、166.42、240.11、320.28and355.82g/m2, in the order of SG>FG>TG>CK>CG.(5) The net amount of soil respiration were482.69456.24、456.06、421.34and429.98g CO2/m2, in the order of CK>CG>TG>SG>FG.(6) Thenet ecosystem productivity (NEP) of CK, CG, TQ FG and SG were-29.06、-49.54、-16.33、29.22and42.85g C/m2, FG and SG ecosystem carbon flus were in a balance state; CG、 TG and CK were in a non-equilibrium state. From the terms of the carbon balance, this area is suitable for FG and SG...