近30年来海伦市耕地土壤有机质和全氮的时空演变

Spatio-temporal Variability of Organic Matter and Total Nitrogen Contents in Arable Soils of Hailun City in Past 30 Years

土壤有机质和全氮含量是衡量黑土肥力质量的重要指标。本研究采用基于土壤学专业知识的属性数据和空间数据连接方法,在GIS技术支持下,研究了黑龙江省海伦市1981、2000和2008年3个时期耕地土壤有机质和全氮含量的时空变化规律。结果表明:1981—2008年,海伦市有超过60%的耕地土壤有机质和全氮含量下降,主要分布在中部和西南部。有机质的下降主要发生前20年(1981—2000),且降幅较大,超过15 g/kg,而近10年(2000—2008)耕地土壤有机质的下降幅度和下降区的面积均有所减小;但近10年(2000—2008)耕地土壤全氮含量下降问题依然严重,中部和西南部累计有超过70%的耕地土壤全氮含量呈下降趋势,其中全氮降幅超过0.50 g/kg区域约占耕地面积的38%。

Soil organic matter and total nitrogen are important indexes in evaluating the fertility of black soil. In this paper, based on pedological professional knowledge, soil property data of collected samples were extended to the full space of the study area, and subsequently, the Geographic Information System techniques was applied to explore the dynamic spatial-temporal change of arable soil organic matter and total nitrogen in three periods （1981, 2000 and 2008） of Haintun City in Heilongjiang Province. Generally, from 1981 to 2008, over 60% of the area of the arable land showed a decrease tendency in organic matter and total nitrogen, which distributed mostly in the middle and southwest regions. The decrease of organic matter mostly happened during the period 1981-2000 with a high decrement （over 15 g/kg）. In contrast, during the period 2000 -2008, the decrements of organic matter and the area of arable land that organic matter decreased became less, while at the same duration, the decrease of total nitrogen was stitl severe, in the middle and southwest regions over 70% of the arable land showed a decrease in total nitrogen and among of which 38% decreased over 0.50 g/kg.