小兴安岭典型农田生产-畜禽养殖系统氮素流动特征

为了解小兴安岭地区农田生产-畜禽养殖系统氮素投入与利用情况,以伊春市带岭区为研究区域,采用物质流分析方法,分析了2007~2015年该区氮素输入、迁移、转化和输出过程,核算了该地区农田生产与畜禽养殖氮素流动通量、流动效率及环境负荷。结果表明：2007~2015年带岭区农田生产系统与畜禽养殖系统单位面积氮素流动通量均呈上升趋势,且在2007~2012年上升幅度较大；畜禽养殖数量、农作物种植结构是影响带岭区氮素流动通量的重要因素；农田生产系统氮素利用率平均为64%,作物能较有效利用氮素；畜禽养殖系统氮素利用率约为19%,存在着较大提升空间；带岭区环境氮负荷呈现逐年增加趋势,畜禽养殖数量增加过快,粪尿氮素损失是环境氮负荷增加的主要原因。建议加强畜禽养殖科学管理,合理控制养殖规模,提高粪尿利用率,同时尽可能减少化肥氮投入,促进农田生产-畜禽养殖系统向高效、可持续方向发展。

Characteristics of Nitrogen Flow in Typical Crop Production-Livestock Breeding System in Xiaoxing'an Mountains

To understand the nitrogen input and utilization of crop production-livestock and poultry farming system in the area of Xiaoxing''an Mountains, Dailing District of Yichun City was selected as the study area. The material flow analysis method was used to decipher the processes of nitrogen input, migration, transformation and output. The nitrogen flux, production efficiency and environmental load in crop production-livestock and poultry farming system were calculated. The results showed that from 2007 to 2015, the nitrogen flux per unit area of the crop production system and the livestock and poultry farming system in Dailing District tended to increase, and this increase trend was much obvious from 2007 to 2012. The quantity of livestock and poultry farming and cultivation structure of crops were important factors affecting nitrogen flux in the study area. The average nitrogen utilization rate of crop production system was 64%, indicating that crops could effectively use nitrogen. The nitrogen utilization rate of livestock breeding system was about 19%, which remained large room for improvement. The environmental nitrogen load had increased year by year in concomitant with the fast growing number of livestock and poultry farming. The nitrogen loss of manure and urine could thus be the main reason for the increase of nitrogen load to environment. To reduce the environmental nitrogen load, it is commanded to strengthen the management of livestock breeding, reasonably control the number of livestock and poultry, improve the utilization of manure and urine, and at the same time make an effort to reduce the over-input of fertilizer-sourced nitrogen, which together promote the crop production and livestock and poultry farming system towards efficient and sustainable development.