农业生态经济系统耦合是一个复杂的过程,是潜变量与潜变量、潜变量与可测变量及可测变量之间相互作用的结果,结构方程模型的建立很好地描述了这一复杂关系。通过对吴起县、安塞县和宝塔区共建的中尺度生态农业建设试验示范区、米脂县等3个典型区域所代表的黄土丘陵区及其各个区域农业生态经济系统结构方程模型的建立与运算,结果表明:在"退耕还林还草工程"等外力作用下,农业生态经济系统运行模式基本揭示了农业产业与农业资源相互耦合这一本质规律,但现状耦合模式并未充分利用农业资源,系统耦合效果较低。农业产业与农业资源对系统耦合的影响系数分别为0.54和0.16,农业产业和农业资源之间的相关系数只有0.28,即农业资源没有很好地支撑产业的发展,导致农业生态经济系统耦合效果不明显,存在着局部相悖的态势,潜伏了林草资源与其相关产业链网缺失现象。为此,需要强化农业产业与农业资源的互动过程,特别要发展林草及其相关产业,促进林草资源的有效利用,促使系统耦合效果的不断提高,增加经济效益。

Coupling relationship of agricultural eco-economic system is a complex process, and it is an interactive result of latent variable and latent variable, latent variable and measurable variable and measurable variable and measurable variable. The complex relationship can be described sufficiently by construction of structural equation model. The results of the structure equation model of three typical areas of Wuqi County, mesoscale eco-agricultural demonstration experiment built by Ansai County and Baota District, and Mizhi county represent loess hilly-gully region, and the establishment and operation of each region indicate that the operation mode of agricultural eco-economic system reveals essential pattern of mutual coupling of agricultural industry and agricultural resources basically with the outside force of Grain for Green Project,but the status of coupled model does not make full use of agricultural resources, and the system coupling effect is low, the impact coefficients of agricultural industry and agricultural resources to the system coupling are 0.54 and 0.16, correlation coefficient between the agricultural industry and agricultural resources is only 0.28, that is to say, industrial development is not well supported by agricultural resources, which resulted in a nonobvious agricultural eco-economic system coupling effect, the existence of local "contrary to" posture, the potential loss phenomenon of forest and pasture resources associated with the industrial chain net. Therefore, the continuous improvement of the system coupling effect and increase economic benefits, the interactive process of agricultural industry and agricultural resources should be strengthened, in particular, the grass and trees and related industries should be developed. The effective use of forest and pasture resources should be promoted.