乡镇尺度耕地生产能力实现程度分析与实证

该文从耕地单产实现程度、播种面积实现程度和耕地总产实现程度3个方面来表征耕地生产能力实现程度的计算方法。区域尺度上的小麦、玉米可实现单产是采用前沿生产函数、区试产量和近5 a高产水平等多种方法进行确定，地块尺度的小麦和玉米的可实现单产依据农业生态区法（agricultural ecological zone，AEZ）进行修正得到。乡镇尺度上的小麦和玉米的可实现单产分别采用尺度下移和尺度上移的方法将地块尺度的小麦玉米可实现单产转化为乡镇尺度的可实现单产。应用此核算方法对北京市大兴区1982、2000和2006年3个时期的乡镇尺度耕地生产能力实现程度的分析结果表明：大兴区区域尺度的耕地生产能力实现程度实现程度在1982年出现最高值，并在1983-1998年的较长时期呈现小幅摆动但基本保持在35%～45%之间，而在1998年以后则呈现大幅下降的趋势，并在2004年以后出现一定幅度上升；大兴区乡镇尺度1982年实现程度最高；与1982年相比，2000年所有乡镇都大幅降低，2006年比2000年有所增加，但仍低于1982年；乡镇尺度耕地生产能力实现程度存在显著的空间分异；大兴区区域尺度耕地生产能力实现程度与乡镇尺度耕地生产能力实现程度变化规律基本一致。该文构建的乡镇尺度耕地生产能力实现程度的分析方法为从宏观尺度研究耕地生产能力差异化提供了借鉴。

Method and empirical research on the realization degree of arable land production capacity at town level

This paper brought out the calculation method for the arable land production capacity realization degree at town level, and Daxing district area was taken as the case study to certify the method validation. The arable land production capacity realization degree was divided into three parts including the crop yield realization degree for both wheat and maize, crop sown area realization degree and the total grain productivity realization degree. The calculation of the available crop yield is the key to the arable land production capacity. The main methods including frontier production function, regional test yield, and the highest appointed productivity in the recent five years were introduced to achieve the available yield per hectare at regional scale, and the crop available yield per hectare based on AEZ method at plot scale was acted as the auxiliary method. The finial crop available yield per hectare at town scale was determined by up-down scale and down-up scale methods. Realization degree of arable land production capacity at town level in three times including 1982, 2000, and 2006 was analyzed. The results showed that: the realization degree of the arable land production capacity at region scale was the highest in 1982, the lowest in 2006 and middle in 2000. In addition, the realization degrees of arable land production capacity at town scale were the highest in 1982, but decreased sharply in 2000 compared with the year of 1982. The realization degrees in 2006 were higher than that in 2000, but still lower than that in 1982. There were spatial and temporal variations for the realization degrees of arable land production capacity at town scale, however, the most importantly was the same changing tendency of the realization degree of arable land production capacity at both county and town scale across Daxing county in three periods. This method can provide a reference for the calculation of the realization degree of arable land production capacity at large scale.