基于STIRPAT扩展模型平塘县农业水足迹变化及驱动机制研究

Study on the change of agricultural water footprint and driving force mechanism based on STIRPAT extended model in Pingtang County

平塘县水资源短缺问题突出,农业生产使得水资源匮乏日益加剧,因此,该地区急需明晰农业水资源利用关键影响因素,以达到构建低水耗高效农业生产模式,提高水资源利用效率目标。利用水足迹核算模型,定量测算2001-2015年平塘县农业用水状况,在经典IPAT环境压力等式基础上,从人口、经济、技术、城镇化、膳食结构、气候6个方面,构建水足迹STIRPAT扩展模型,剖析平塘县农业水足迹变化主要驱动因素。结果显示:平塘县农业水足迹从2001年6. 02×108m3增加到2015年8. 60×108m3,增加了42. 86%,绿水、蓝水的增加主要由于农业产业结构调整、种植技术改进、作物新品种推广等,灰水水足迹快速增长主要由于化肥大量使用;平塘县农业水足迹驱动因子贡献率由大到小排序为:膳食结构>降水量>人口>经济>技术>城镇化,上述驱动因子每变化1%,分别导致农业水足迹总量变化-0. 1071%、0. 09393%、0. 0684%、0. 0585%、0. 0581%、0. 0453%。平塘县属于典型喀斯特峰丛洼地区,由于特殊"二元"结构特征,地表调蓄功能极弱,农药化肥大量使用,导致灰水对农业用水增长率的贡献率较大,而经济欠发达,生活水平低,以植物性食物为主的膳食结构,在一定程度节省农业用水。

Pingtang County is facing severe water shortage and the agricultural water use makes the situation worse; therefore,there is an urgent need to clarify the key factors affecting the utilization of agricultural water resources in this area,to construct high efficiency agricultural production model,and to improve water resources use efficiency. Using the water footprint research model,quantitative estimation of agricultural water use in Pingtang County from 2001 to 2015 was carried out,and the STIRPAT extension model of water footprint variation was constructed considering six factors including population,economy,technology,urbanization,dietary structure and climate and based on the classical IPAT environmental pressure equation. The main driving factors of agricultural water footprint change in Pingtang County was analyzed. The results show that: the water footprint of Pingtang County increased by 42. 86% from 6. 02× 108 m3 in 2001 to 8. 60 × 108 m3 in 2015. The increasing footprint of green water and blue water was due to the adjustment of agricultural industrial structure,the improvement of planting technology,the ex-tension of new crop varieties. The rapid growth of ash water footprint was mainly due to the heavy use of chemical fertilizers; The driving contribution of the driving factor of agricultural water footprint change in Pingtang County was ranked from large to small as follows: dietary structure > precipitation > population > economy > Technology > urbanization,and every 1% change in the above driving factors will cause the change of the total agricultural water footprint-0. 1071%,0. 09393%,0. 0684%,0. 0585%,0. 0581%,and 0. 0453%,respectively. Pingtang County belongs to a typical karst peak cluster depression,and surface storage function is very weak,due to the special surface and underground " dual" structural characteristics. The contribution rate of grey water to agricultural water use growth rate is large,due to heavy use of pesticides and fertilizers. However,the economy is underdeveloped,with low living standard,the dietary structure are mainly vegetative food,which saves agricultural water to a certain extent.