中国耕地数量变化与耕地保护政策关系的实证分析

An Empirical Research of the Relationship Between Changes in Cultivated Land Quantity and Cultivated Land Protection Policies in China

以耕地数量的统计数据和耕地保护政策的颁布、实施为基础,借助经济计量学理论以及Eviewes 5.1软件,运用协整分析、Granger因果关系检验和脉冲响应等分析方法分析了改革开放以来中国耕地数量变化与耕地保护政策之间的互动关系.结果显示:(1)耕地数量变化与耕地保护政策之间存在一种长期均衡关系,说明二者之间存在着某种机制在制约着变量的运动,使二者之间短期内的偏离不会太远,长期则会走向均衡;(2)耕地数量变化与耕地保护政策之间存在单向的因果关系,即耕地数量变化是耕地保护政策的Granger原因,而耕地保护政策不是耕地数量变化的Granger原因.(3)脉冲响应以及方差分解表明,耕地数量变化对耕地保护政策具有较为持续的促进作用,且作用程度随着滞后期的加大而加强;耕地保护政策具有较强的惯性,主要受其自身以前水平的影响,因此耕地保护政策对耕地保护的促进作用不太显著.这也从一个侧面佐证了Granger因果检验的结果.因此,应制订长期而非短期的策略,强化耕地保护政策理论研究,加大耕地保护政策的制定、执行和监督力度,这是解决耕地过快减少问题的重要途径.

Based on the statistical data of cultivated land quantity and introduction and implementation of cultivated land protection policies in China during 1978-2007,aided by the econometrics theory and Eviewes 5.1 software,and using the method of co-integration analysis,Granger causality test and impulse response functions,the interaction between cultivated land quantity change and cultivated land protection policies in China is analyzed in this paper.The response of cultivated land quantity to cultivated land protection policy impulse is remarkable and the change of cultivated land quantity impulse can explain the policies for cultivated land protection to a great extent（33%）;the response of cultivated land protection policies to cultivated land quantity impulse is non-remarkable and the cultivated land protection policy impulse can only explain the change in cultivated land quantity to a small extent（1.7%）.Cultivated land quantity is influenced by its own fluctuation,and so are the cultivated land protection policies.Therefore,it is necessary to protect cultivated land by strengthening theoretical research and implementation of the cultivated land protection policies.