基于GIS技术的中国农田氮素养分收支平衡研究

该文基于统计数据、调查数据、图形数据以及已经公开发表的文献资料中的数据，详细研究了中国2000多个县域单元农田氮素养分的收支平衡状况，并将研究结果利用GIS技术进行了空间表达。研究发现，中国农田氮素投入总量为34.22×10⁶ t，农田氮素支出总量为31.57×10⁶ t，农田氮素处于盈余状态，盈余总量为2.65×10⁶ t；在县域层面上，农田氮素处于亏缺的县域单元数占全部县域单元数的37.68%，其耕地面积占全国总耕地面积的43.10%，农田氮素处于盈余的县域无论在数量上还是在耕地面积上都占有绝对优势，亏缺的县域单元离散分布在几乎全国的每个省份；在全国层面上，化学氮肥、有机氮肥、生物固氮、其他来源的氮素养分投入分别占全部氮素投入的76.54%、16.26%、3.10%、4.09%，化学氮肥在所有氮肥总投入中占有绝对优势；人畜粪尿是有机氮肥投入的主要来源；全国农田氮素生物产出总量为19.87×10⁶ t，占农田氮素总支出的比重为62.85%，在省域水平上，黑龙江省农田氮素生物产出占全部氮素生物产出的比例最高，达85%。

Balance of field nitrogen nutrient input/output using GIS technology in China

This study presents a detailed investigation of the supply and demand status of nitrogen for more than 2000 counties across the country. In the study, statistic data, field survey results, graphic data and a number of datasets published in the literature were analyzed and the spatial distribution of nitrogen balance was presented with GIS technology. Results show that the total national input of nitrogen for cropland is 34.22×10⁶ t, but only 31.57×10⁶ t of which has been used, inducing a net excess supply of 2.65×10⁶ t. Despite this overall excess, the number of counties with a deficit supply of nitrogen is 37.68% of the total and the cropland of these counties is 43.1% of national total cropland. These counties are located in each province. At national scale, chemical nitrogenous fertilizer, organic nitrogenous fertilizer, biological nitrogen fixation and other nitrogen supply occupy 76.54%, 16.26%, 3.10% and 4.09% of the total nitrogen supply, respectively. While the contribution of chemical nitrogenous fertilizer plays a dominant role in the overall supply, the excrement and urine of human and animals are the main sources in organic nitrogen supply. The biological output of nitrogen from national cropland amounts to 19.87×10⁶ t, weighting 62.85% of the total expenditure. Among provinces, the weight of the biological output of nitrogen in Heilongjiang Province is the highest, nearly 85%.