挠力河流域水土资源平衡及耕地合理利用规模特征

水土资源平衡是耕地合理开发与利用的前提,为定量评估粮食主产区水土资源平衡关系,促进耕地可持续利用,该研究提出“以水定地”的耕地配置模式,并以三江平原腹地的挠力河流域为研究区,在多源水土信息数据支持下,依据农田土壤水分平衡原理构建水土资源平衡模型,以评估水土资源平衡态势,进而揭示该流域耕地合理利用规模特征。结果表明:1)2000年以来,挠力河流域水田持续扩张,旱地轻度萎缩,至2018年其水田化系数已达37.33%,垦殖率为62.61%。旱地和水田的水分胁迫蒸散能力处于同一水平,但水田的水分亏缺量显著高于旱地;2)当前,挠力河流域的灌溉供水量范围为21.23~211.91 mm,富锦市、友谊县和集贤县处于水资源超载状态,且水田均呈“土多水少”状态,饶河县、宝清县、七台河市和双鸭山市辖区则“土少水多”;3)依据“以水定地”耕地配置模式,该流域水田面积可增加11.02万hm2,对应的水田化系数控制在44.76%以下。富锦市、友谊县和集贤县应适度控制或减小水田利用规模,宝清县应成为未来“旱改水”的重点备选区。研究结果对挠力河流域乃至三江平原的耕地有序开发及保障农业可持续发展具有重要现实意义。

Balance between land use and water resources for cultivated land and its appropriate scale in Naoli River Basin

Abstract: Utilization of water resources in the Sanjiang Plain depends largely on the agricultural structure, where most dry land crops has changed into rice since 2000. It is necessary to explore the balance of soil and water resources, thereby to obtain an optimal utilization scale of cultivated land for the sustainable development in China. In this study, the Naoli River Basin was taken as the research area, which was an important commodity grain production base in China. Most datasets were related to water and soil resources, including the remote sensing information, meteorological station, and spatial distribution of cultivated lands. A balance model of soil and water in a farmland was established according the fundamental principle. An evaluation was made to clarify the allocation status of water and soil resources in Naoli River Basin. A quantitative investigation was carried out to obtain an optimal scale on cultivated land suitable for development and utilization, combined with crop irrigation data. The results showed that: 1) The current reclamation rate of Naoli River Basin was 62.61%, and its paddy field coefficient was 37.33%, which was in the middle stage of paddy fields. Evapotranspiration under water stress was the same for dry land and paddy field. The river basin also showed that the water deficit for paddy field was significantly higher than that for dry land; 2) The supply of irrigation water in Naoli River Basin was from 21.23 mm to 211.91 mm, where the demand of irrigation water in paddy field was higher than that in dry land. Water resources in Fujin City, Youyi and Jixian County were in the overload state, where there were more land resources and less water resources for the paddy fields. The current water resources supply conditions cannot meet the demand of cultivated land water; 3) Besides, water resources in Qitaihe City, Shuangyashan City, Raohe and Baoqing County were in the overload state, showing the obvious characteristics of less land resources and more water resources. A suggestion can be that the expandable paddy field area of Naoli River Basin cannot exceed to 1 101.80 km2 in the future, where the coefficient of paddy field was controlled below 44.76%. The scale of paddy fields can be appropriately reduced in Fujin City, Youyi and Jixian County. In Baoqing County, the key dry land can be converted into paddy fields. The findings can be used as a sound references for the cultivated land management in the Naoli River Basin and the Sanjiang Plain.