基于能值理论的农田—畜禽生产系统可持续动态

为了解我国东南丘陵山区农业生产动态及其可持续性,以福建典型山区德化县为例,构建废弃物能值比例、环境污染能值负产出等指标,运用能值理论定量分析德化县2007—2016年农田—畜禽生产系统投入产出、环境负荷及可持续性的变化。结果表明：德化县农田—畜禽生产系统能值投入以购买能值为主,占能值总投入的68%~79%,水资源能值约占21%~31%;畜禽子系统能值产出占72%以上;能值密度在2.68×10¹²~3.33×10¹² sej·m^-2之间波动上升,净能值产出率下降40%,环境负荷明显加重,2015年以来有所减轻;可持续发展指数在2007—2010年短暂上升后快速下降,由1.14降至0.42。从构建的指标来看,系统废弃物能值比例有所下降,环境污染能值产出减少约22%,综合经济效益和废弃物利用情况,近年来可持续发展状况逐渐好转。德化县目前正处于农田—畜禽系统产出结构调整期,应增加系统内部反馈能值用量,控制化肥、饲料投入,提高废弃物利用率,以实现可持续发展。

Dynamic research on sustainable development of farmland-livestock production system based on emergy theory

To understand the agricultural production dynamics and sustainability in the hilly areas of southeast China, this paper took Dehua county, a typical mountainous area in Fujian province, as an example to quantitatively analyze the changes of input, output, environmental load and sustainability of farmland-livestock systems from 2007 to 2016, and constructed the indicators of waste emergy ratio and environmental pollution emergy negative output. The results showed that the input of the farmland-livestock system in the study area was mainly based on the purchasing emergy, accounting for 68%-79% of the total emergy input, and the emergy of water resources accounted for 21%-31%. The emergy output of livestock systems accounted for more than 72% of the total output. And the emergy density fluctuated between 2.68×10¹² and 3.33×10¹² sej·m^-2, and emergy per person increased from 1.23×10¹⁶ sej to 1.72×10¹⁶ sej. The net emergy yield ratio decreased by 40%, and the environmental load increased significantly, which could have been maintained since 2015. The emergy sustainability index fell rapidly from 1.14 to 0.42 after a brief rise in 2007-2010. From the indicators of construction, the proportion of system waste emergy decreased, and environmental pollution emergy output decreased by about 22%. In terms of comprehensive economic benefits and waste utilization, the sustainable development of Dehua county has gradually improved in recent years. Dehua county is currently adjusting its output structure of farmland-livestock system. It should increase the amount of feedback emergy in the system, control fertilizer and feed input, and improve waste utilization to achieve sustainable development.