Study On Terrestrial Soil Nitrogen Pool In China

Among the elements required by plant, nitrogen is the largest one, and at the same time it is a limited factoring the signal plant .natural ecosystem and artificial ecosystem. The nitrogen storage of the soil is about as three times as of the plant in the nitrogen cycle of the terrestrial ecosystem. In forest ecosystem system the soil nitrogen storage accounts for 90%~95% of the whole ecosystem nitrogen storage, there for studying the nitrogen in the soil have got the important function to whole terrestrial ecosystem . soil nitrogen pool is the main body of terrestrial carbon pools, so it's change will possibly result in relatively great change of atmosphere N2O concentration, and, it's change will also affect global climate change. Meanwhile, The nitrogen in the soil can also cause the water pollution through soil water infiltration and surface runoff. Studying the Chinese terrestrial ecosystem soil nitrogen storage can provide the basic data for studying the terrestrial ecosystem nitrogen cycle, and the emission of soil nitrogen should be considered in future research. The nitrogen in the soil can also cause the water pollution through soil water infiltration and surface runoff. Studying the Chinese terrestrial ecosystem soil nitrogen storage can provide the basic data for studying the terrestrial ecosystem nitrogen cycle, and the emission of soil nitrogen should be considered in future research.This paper synthetically summarized current research on terrestrial nitrogen cycle and soil nitrogen cycle, Meanwhile, uncertainties of terrestrial nitrogen cycle were discussed. The global diversified ecosystem nitrogen and carbon storage was comparative thoroughly estimated through different life zone. The global organic nitrogen storage was estimate by the C/N ratio. But the number of the soil profile that they used was very small. Now, there is not sufficient research on soil nitrogen pool and its spatial distribution research in China. With the construction of geographically referenced database based on second national soil general survey materials, including the data of soil profiles physical chemistry property, soil profiles depth, soil nitrogen content, soil bulk density, and the support of Geographic Information System, this paper systematically quantified the soil nitrogen pool. Moreover, this paper principium establish the database of soil profile. Meanwhile, this paper using geostatistics combined with Geographic Information System analyzed the spatial character of 0~30cm and 0~100depth soil nitrogen density and storage in China.In the paper, the main results are brought forth in five aspects as follows: (1). The analysis of statistics the characteristic indicated that the variation coefficient of the soil nitrogen density of 0~30cm depth is lower, the variation coefficient is only 3.6%, the variation coefficient of the nitrogen density of 0~ 100cm depth is much bigger than that the 0~30cm depth, itis 100%.Based on the second national soil general survey material, the average soil profile depth is 101cm, this is in corresponding with skew normal distribution, its standard deviation is 0.0192. The nitrogen density of 0~30cm depth follow lognormal distribution and the nitrogen density of 0~100 depth stand complied with skew normal distribution.(2). The isotropy analyses indicated : the nitrogen density spatial distribution of 0~ 100cm depth displays the interest of moderate spatial correlation ,Its theory pattern accords with the exponential model. But the nitrogen density spatial distribution of 0~30cm depth is the very feeble correlation ,Its theory pattern accords with the spherical model.(3). The anisotropic analysis indicated that: The spatial variability of soil nitrogen of 0~30cm depth is different in every orientation. This indicate that the geometry shape of the spatial distribution of surface soil nitrogen density does not have powerful regular quality in this four orientations. The spatial variability of soil nitrogen of 0-100cm depth have the same variation scale in the direction of...