基于生态生产生活视角的北方农牧交错区土地宜耕性评价

北方农牧交错区是中国生态脆弱地区,土地荒漠化问题突出,土地利用是导致土地荒漠化的主要原因。生态文明建设背景下,研究该区域土地宜耕性对促进该地区生态环境保护和土地资源科学利用具有重要意义。该文以位于北方农牧交错区的科尔沁左翼后旗为例,基于生态、生产、生活的视角,构建评价指标体系对土地宜耕性进行评价,表明,现状耕地中不适宜耕作的耕地面积为15 996.87 hm~2,占耕地总面积的5.339%,因生态、生产、生活因素使得耕地不适宜耕作的面积分别为7 519.23、9 337.23、6 039.99 hm~2。建议在退耕还林工程中优先对该部分耕地进行退耕。适宜耕作的草地面积为197 195.94 hm~2,占草地总面积的32.18%,即有三分之一左右的草地可以开发利用为耕地。但是,从土壤适宜性和地形条件两方面对适宜耕作的草地进行分析,揭示出适宜耕作的优质草地面积比例很小。为避免土地开发利用导致农牧交错区生态环境的破坏和荒漠化的扩张,建议在跨省域耕地占补平衡中应当优先开发利用质量较高的耕地后备资源,且需始终坚持国家统筹。

Land cultivation suitability evaluation of agro-pastoral ecotone in northern China based on aspects of ecology, production and life

Abstract: Agro-pastoral ecotone in northern China is fragile in ecology. Desertification is the prominent eco-environmental problem which is mainly induced by unreasonable land use in this area. In the background of ecological civilization construction in China, it is significant to study land suitability for cultivation in the agro-pastoral ecotone in northern China to prompt ecological protection and scientific utilization of land resource. Taking Horqin Left Back Banner as a case study, from the aspects of ecology, production and life, this paper constructed the evaluation index system to evaluate land suitability for cultivation. The results showed that the unsuitable cultivation area in cultivated land in Horqin Left Back Banner was 15 996.87 hm2 accounting for 5.339% of total cultivated land area. Owing to ecological, production and living factors, the unsuitable cultivation area of cultivated land were 7 519.23, 9 337.23 and 6 039.99 hm2 and their proportions were 40.78%, 32.84% and 26.38%, respectively. There were 6 unsuitable cultivation types including ecology; production; ecology and production; ecology and life; production and life; ecology, production and life. We reckon that unsuitable cultivation land should be de-farmed firstly in Grain for Green Project. The grass land suitable for cultivation was 197 195.94 hm2 accounting for 32.18% in total grass land area. Namely, about a third of the grass land could be reclaimed into cultivated land in Horqin Left Back Banner. However, it was found that the proportion of high quality grass land suitable for cultivation was very small from perspectives of soil suitability and topographic conditions. From the perspective of soil suitability, the most suitable, the moderate suitable and the low suitable were 26 058.42, 34 347.78, 136 789.74 hm2, accounting for 13.214%, 17.418%, 69.367% of the total grass land suitable for cultivation, respectively. From the perspective of topography condition, when the micro topography index were [1.5, 1.6), [1.6, 1.7), [1.7, 1.8) and [1.8, 1.9) ,the grass land areas were 0.18, 0, 8.1 and 277.29 hm2, accounting for 0, 0, 0.004% and 0.141% of the total grass land area suitable for cultivation, respectively. However, when the micro topography index were [1.9, 2.0), [2.0, 2.1), [2.1, 2.2), the grass land area were 82 389.24, 112 996 and 1 525.05 hm2 respectively, accounting for 41.780%, 57.301% and 0.773% of the total grass land area suitable for cultivation. From two aspects of soil suitability and topography condition, the grass land area proportion of soil suitability for most grade and micro topographic index for [1.5, 1.9) was only 0.039% to the total grass land area suitable for cultivation. And the grass land area proportion of soil suitability for most and moderate grade and micro topographic index for [1.5, 1.9) was only 0.085% to the total grass land area suitable for cultivation. In order to avoid the destruction of ecological environment and the expansion of desertification caused by the reclamation of low quality grass land, it is suggested that priority should be given to the high quality reserved cultivated land resource in reclamation and the national coordination should be maintained in cultivated land balance across provincial region.