现代农业生态系统能值演替分析--以河北省曲周县为例

以河北省曲周县为例，研究了现代农业生态系统的能值演替情况。结果表明，曲周农业生态系统年总投入能值和总产出能值均呈增加趋势，其中农业投能以系统以外的化石能投入为主，系统环境资源投能的绝对数也在增加，主要表现在对地下水的开采利用上；总产出能值先以种植业产出能值占绝对优势后演替为农牧结合同时兼顾林业和渔业发展的能值产出形式，但农牧业系统多样性降低；农业发展在全国居于较好水平，仍有较大的发展潜力，但能值产出效率增加幅度减慢，系统连接网络不佳，优势度呈下降趋势，主要表现为林业和渔业的子系统能值产出占总产出的比例太低。

Analysis on Succession of Energy in Modern Agro-ecosystem--as a case in Quzhou county, Hehei province

The paper studies succession of energy on modern agro-ecosystem as a case in Quzhou county,Hehei province,and the result indicates as follow: the energy input and output annually presents the increasing trend with chemic-petrolic energy being main in energy input structure and the utilization of groundwater being main in the input of the increasing environmental resource;total energy output structure becomes gradual planting output energy being leading into the integration of farming and animal husbandry with the development of forestry andfishery,besides the variety is reducing to farming and animal husbandry;the development of agriculture is in better level and hold better potential,but the increment on efficiency of energy output decreases with systemic structure being unreasonable and the decreasing predominance degree of the system,it is main reason that the proportion of forestry and fishery energy output is lower.