摘要
摘要:针对农牧业快速发展过程中氮素大量投入引起的一系列问题, 本文以江苏省为研究对象, 探讨1998—2018年农牧系统氮素流动特征及其环境效应, 以期为区域氮素资源管理提供科学参考。研究基于食物链养分流动模型(NUtrient flows in Food chains, Environment and Resources use, NUFER), 结合统计年鉴数据、调研数据和文献数据, 定量分析江苏省农牧系统氮素账户平衡、各系统氮素利用效率、氮素循环利用和损失情况, 并基于结构方程模型探讨农牧系统中经济-资源-环境间的关系。1998—2018年, 江苏省作物子系统在系统氮素总输入逐步减少的情况下实现了产品携出氮素的较大增长, 作物主副产品氮素携出量由8.31×10⁵ t增至1.20×10⁶ t, 氮素损失总量也在不断降低。对于畜禽子系统, 氮素输入主要包括外源饲料和本地饲料输入, 其中外源饲料是子系统的主要氮素来源; 且本地饲料氮素供给比例在逐年上升, 从1998年的29.32%增长至2018年的44.77%。1998—2018年, 农牧系统氮素利用率由21.39%增至35.00%, 呈上升趋势, 本地饲料、秸秆还田和粪尿还田氮素量逐年上升, 氮素资源循环利用总量由2.54×10⁵ t增至3.00×10⁵ t。从氮素排放损失来看, 20多年来环境排放部分呈下降趋势, 其主要损失途径包括土壤氮素盈余、气体排放损失、水体排放损失和粪污残余损失。结构方程模型核算结果表明江苏省农牧系统的发展过程中, 经济发展和资源减量推动了产品产量和系统效率的提高。总的来说, 受区域发展水平和政策引导, 1998—2018年江苏省农牧体系发展较快, 规模不断扩大, 资源利用相对高效, 环境排放逐渐减少; 但农牧子系统之间的发展不平衡, 农牧结合体系规模相对较小等问题仍值得关注。因此, 今后江苏省农牧业的发展应注重作物子系统和畜牧子系统的耦合, 适度扩大生产规模, 以促进本地农牧业更好发展。
关键词:江苏省/
农牧系统/
氮素流动/
NUFER模型/
环境效应
Abstract:With the rapid development of agriculture and animal husbandry, large nitrogen inputs have caused a series of environmental problems. To provide a scientific reference for regional nutrient management, Jiangsu Province, an economically developed region in the Yangtze River Delta, was selected to study the nitrogen flow characteristics in crop-livestock systems from 1998 to 2018 and their environmental effects. The research was based on the NUFER model (NUtrient flows in Food chains, Environment and Resources use, NUFER) and incorporated statistical yearbook data, survey data, and literature data. The nitrogen account balance, nitrogen use efficiency, nitrogen recycling, and loss of the crop-livestock systems in Jiangsu Province were quantitatively analyzed, and the relationships between the economy, resources, and environment of the crop-livestock systems were explored based on a structural equation model. The results showed that from 1998 to 2018, the crop subsystem increased the amount of nitrogen carried by the crop products under the gradual decrease of the total nitrogen imports of the subsystem. Nitrogen carried by the main crops and crop by-products increased from 8.31×10⁵ t to 1.20×10⁶ t. Total nutrient loss also declined. For the livestock-poultry subsystem, nitrogen was mainly introduced via exogenous and local feed; exogenous feed was the main source of nitrogen in the subsystem. The proportion of local feed nitrogen supply increased annually, from 29.32% in 1998 to 44.77% in 2018. From 1998 to 2018, the nitrogen use efficiency of the crop-livestock system increased from 21.39% to 35.00%. The amount of straw to field, local feed, and manure to field increased annually, and the total amount of recycled nitrogen increased from 2.54×10⁵ t to 3.00×10⁵ t. Nitrogen environmental emissions decreased in the past 20 years, and the main sources of loss included soil nitrogen surplus, gas emission loss, water discharge loss, and manure residue. The structural equation model results showed that in the developmental process of the agricultural and animal husbandry systems in Jiangsu Province, economic development and resource reduction promoted improvements in product output and system efficiency. Under the guidance of regional development and policies, crop-livestock systems in Jiangsu Province developed rapidly from 1998 to 2018. The scale of the agricultural and animal husbandry systems had continuously expanded, resource utilization had been relatively efficient, and environmental emissions had gradually decreased. However, there was also a slight imbalance in the development of crop-livestock systems, and there were relatively few combinations of crop-livestock. Future development of the agriculture and animal husbandry systems in Jiangsu Province should focus on coupling the crop and animal husbandry subsystems, moderately expanding the production scale, and balancing the development of agriculture and animal husbandry subsystems to promote local agriculture and animal husbandry.
Key words:Jiangsu Province/
Crop-livestock system/
Nitrogen flows/
NUFER model/
Environmental effects



PDF全文下载地址:

http://www.ecoagri.ac.cn/article/exportPdf?id=437b2ca5-27bd-4432-9147-1e7aa98cf91c