外部环境如何影响农产品流通渠道长度？——一个外生的理论模型与实证检验
How Does External Environment Affect Channel Length of Agricultural Products？——An Exogenous Theoretical Model and Empirical Test

从宏观环境层面，基于农产品流通演进的外生视角构建了一个理论模型，并利用1981-2014年的时间序列数据实证研究了农产品流通渠道长度的演进规律以及影响其演进的外生环境因素。研究发现：农产品流通渠道长度的演变呈现出明显的阶段性特征，表现为渠道长度先变长再变短的“倒U型”演变趋势；居民食品消费支出、消费者延拓性、交通基础设施以及农产品流通政策的市场化导向对农产品流通渠道的长度具有显著的负效应，而居民的老龄化程度对农产品流通渠道的长度却表现出显著的正效应；鉴于各环境变量对农产品流通渠道变革作用方向和影响程度的差异性，未来农产品流通渠道长度的演进还将呈现出一定程度的波动特征。
From the level of macro environment,this paper constructs a theoretical model based on the exogenous perspective of the evolution of agricultural products circulation,and does an empirical study on the evolution law and external environment factors of China’s agricultural products circulation channel by using the data between 1981 and 2014.The result shows that the evolution of China’s agricultural products circulation channel has an obvious stage characteristics,which manifests as the “inverted U” evolution trend. The length of the channel first became longer and then shorter. Resident’s food consumption,consumer extension,transport infrastructure,market-oriented policy of agricultural products circulation had significant negative effects on the length of agricultural products circulation channels. However,the aging degree of residents had significant positive effects. Because of the differences of environment variables which affect agricultural products circulation channel,China’s agricultural products circulation channel will show fluctuation characteristics in the future.