The Research Of Soil Respiration Under Different Managements And Disturbances In The Grassland Of Bashang Area

The grassland soil respiration is a key indicator of the grassland ecosystem carbon cycle,which plays significant role for terrestrial ecosystem carbon cycle and global carbon balance.Also it is an important index of ecosystem health evaluation. We observed in national grassland ecosystem field station which locates in Bashang plateau of Hebei province from April to October of 2015. In order to investigate the response and the main influence factors of grassland soil respiration in different disturbances and management ways, zokor mound disturbance, short-term fencing and long-term fencing, nitrogen addition and phosphorus addition were determined. The main results are as follows:The change of soil respiration in the natural grassland of Bashang plateau had diurnal dynamic obviously. The change of soil respiration appeared only one peak a day, and daily average soil respiration rate appeared at about 9 a.m. So the measurement of the grassland soil respiration in Bashang is more accurate in 8¹0 a.m. Diurnal patterns of soil respiration affected by the temperature: the soil temperature and soil respiration rate present index relationship in the summer and autumn. Their values of Q10 were 2.05 and 2.14, which showed that the heat sensitivity of soil respiration grassland in summer was lower than in autumn in Bashang plateau grassland.In the whole growth season, soil respiration had obvious seasonal dynamic. The interaction effects of zokor mounds and enclosed habitat under the seasonal dynamics of soil respiration was mainly affected by water and heat conditions. Soil temperatures were the main influential factors of soil respiration in three types of habitats. There was a good quadratic function relation between soil respiration rate of short-term fencing grassland and soil temperature. That's also between zokor mound quadrate samples of soil respiration rate and soil moisture. In the dry environment?soil moisture<9.0%?, soil respiration was mainly affected by soil moisture. there was a good quadratic function relation between long-term fencing samples of soil respiration and soil moisture. The relationship between the short-term fencing samples of soil respiration and soil moisture could be expressed by the exponential equation. The regulation effect of environmental factors on soil respiration was weak in nitrogen and phosphorus addition test. The main factor on the seasonal change of soil respiration was soil organic matter. There was third power function between them.11-year fencing significantly enhanced soil respiration, which was conducive to the formation of micro environment microclimate, and could restore the structure and function of degradation grassland ecosystem. Zokor mound disturbance significantly reduced soil moisture and inhibited the soil respiration to some extent. Nitrogen addition enhanced soil respiration. From the point of view of the whole growth season, it did not cause significant influences. But the addition of nitrogen had significant effect of short-term promotion;phosphorus addition to a certain extent, inhibited soil respiration, and the impact was not significant.Soil respiration in non-growth season should not be ignored in Bashang grassland, the valuation of natural grassland soil respiration fluxes in Bashang area equaled130.39 g C·m^-2·a^-1.