内蒙古典型草原区土壤氮储量分布研究

Distribution of soil nitrogen storage in the typical steppe of Inner Mongolia

基于野外调查数据、气象站观测数据和草原放牧统计数据,利用相关分析和逐步回归方法识别区域土壤氮储量的主要影响因素,建立了土壤氮储量与放牧压力指数和降雨两个影响变量的地理加权多元回归克里金模型,并利用该模型预测了内蒙古典型草原土壤氮储量的空间分布。结果表明:降水和放牧压力指数与土壤氮储量具有显著的相关关系;研究区域0-50cm土壤氮储量在0.01kg·m-2和1.56kg·m-2之间;土壤氮储量空间分布整体上呈自东北向西南递减的特征。区域降水减少对土壤氮储量累积具有不利的影响,而通过降低草原载畜率或采用草场封育措施降低放牧压力则有助于提高区域土壤氮储量。

In order to identify the major influence factors by using correlation analysis and stepwise regression, we set up a geographically weighted regression kriging model （GWRK） between soil N storage and precipitation and grazing pressure index and predicted the spatial distribution of soil N storage in the typical steppe of Inner Mongolia, China. The data was derived from multi - source data of field survey, meteorological and statistical data. Results showed that there were significant correlations between soil N storage and precipitation and grazing; the soil N storage varied from 0.01kg · m-2 to 1.56kg · m-2 in the 50cm soil depth; and the soil N storage di- minished from northeast to southwest in the spatial distribution. Regional precipitation reduction has adverse in- fluence on the soil nitrogen storage, but decreasing stocking rate or adopting pasture fostering measures to lower grazing pressure is helpful to the soil nitrogen storage increase.