山东省冬小麦-夏玉米轮作体系土壤氮素盈余指标体系的构建与评价——以德州市为例

山东省德州市是我国重要的粮食生产基地,大量施用氮肥以及氮素流失是该地氮素污染的重要原因,设定合理的氮素盈余指标体系迫在眉睫。本研究以田间试验研究和文献荟萃为基础,探究德州市冬小麦-夏玉米轮作氮素盈余情况,建立该地氮盈余指标体系,并运用欧氏距离法对德州市当前氮素管理指标进行评价。结果表明:德州市整个冬小麦-夏玉米轮作体系轮作周期氮素盈余量为196.84 kg N·hm~(-2)·a~(-1),小麦季氮素盈余量为111.07 kg N·hm~(-2),玉米季氮素盈余量为85.77 kg N·hm~(-2)。氮素盈余量在30～70 kg N·hm~(-2)·a~(-1)时为德州市整个轮作周期氮素盈余量推荐值;德州市小麦季氮素盈余量推荐值为10～50 kg N·hm~(-2);德州市玉米季氮素盈余量推荐值为20～60 kg N·hm~(-2)。在氮素的损失方面,氨挥发以及淋洗是氮素损失的主要去向。小麦季的氮素污染程度高,玉米季氮素污染程度相对较低。运用欧氏距离法计算德州市氮素管理水平(A值)为0.63,属于中级管理水平。综上,德州市冬小麦-夏玉米轮作体系农田氮素含量较高,从而导致氮素大量损失。加强氮素管理水平,提高氮素利用率是德州市氮素资源管理的长期任务。

Construction and evaluation of a soil nitrogen surplus index system for the wheat maize rotation system in Shandong Province, China: A case study of Dezhou City

The city of Dezhou in Shandong Province is considered an important center for grain production in China. However, the application of nitrogen fertilizer and nitrogen loss are important sources of nitrogen pollution in this area. Therefore, it is important to determine a reasonable nitrogen surplus index system. Based on field experiments and literature reviews, this study explored the nitrogen surplus of the wheat maize rotation system in Dezhou City, and established a nitrogen surplus index system. According to the results, the surplus amount of nitrogen in the entire rotation cycle, wheat season, and maize season was 196.84 kg N·hm^-2·a^-1, 111.07 kg N·hm^-2, and 85.77 kg N·hm^-2, respectively. In addition, the recommended value of nitrogen surplus in the entire rotation period, wheat season, and maize season in Dezhou City was 30~70 kg N·hm^-2·a^-1, 10~50 kg N·hm^-2, and 20~60 kg N·hm^-2, respectively. Nitrogen fertilizer was the main source of nitrogen input, while ammonia emissions, leaching, and runoff were the main pathways of nitrogen loss. Nitrogen pollution was serious in the wheat season and relatively light in the maize season, and furthermore, nitrogen loss during the entire rotation cycle was serious. The evaluation theory of Euclidean distance accurately calculated the level of N management in Dezhou City with a score of 0.63, which corresponds to a middle level of N management. In summary, this study analyzed the nitrogen surplus situation and established an initial index system of nitrogen surplus in Dezhou City, which also provided the basis for recommending a scientific and reasonable nitrogen management system.