耕地结构变化下水土资源匹配时空特征效应分析——以黑龙江省为例

基于耕地利用水资源的供需视角,在综合考虑耕地利用类型、作物种植结构、作物生长期等条件的基础上,结合黑龙江省的国家气象站数据,对耕地利用需水量与有效供水量从微观尺度上进行分析,并以此对1990—2018年内不同生长期耕地利用水土资源匹配的时空动态进行分析。结果表明：1990—2018年间黑龙江省耕地结构不断变化,旱改水现象在2010— 2018年间最为普遍;作物生育前期与中期需水量较多,后期需水量较少,需水量逐年上涨,与水田占比变化保持较为一致,并且空间上需水量高值地区偏移规律与同时段内的旱地水田化现象保持高度一致;1990—2018年间,作物各生育期水土资源匹配程度均先降后升,大部分的水土资源匹配高值地区分布在有效降水量的高值地区与旱地地区的交接地带,可见天然降水仍是满足耕地作物用水的主要来源;近年来三江平原南部地区水土资源匹配程度严重下降,粮食单产下滑,建议该部分地区减少旱改水工程量,同时,松嫩平原西部地区水土资源匹配水平与粮食单产逐年上升,可适当进行旱改水工程。

Analysis of spatio-temporal characteristics and effects of land and water resources matching under cultivated land structure change: A case study of Heilongjiang province

From the perspective of supply and demand of water resources for cultivated land use, this paper comprehensively considered cultivated land use type, crop planting structure, crop growing period and other conditions, combined with the data from the national meteorological stations in Heilongjiang province, and explored the water demand for cultivated land use and effective water supply on the micro scale. Based on this, the spatio-temporal dynamics of land and water resources matching in different growing periods from 1990 to 2018 were analyzed. The results show that: the cultivated land structure of Heilongjiang had been changing from 1990 to 2018, and the phenomenon of changing from dryland to paddy was the most common from 2010 to 2018; the demand for water was greater in the early and middle stages of crop growth compared with the later stage. The water demand increases year by year, which is consistent with the change of paddy proportion, and the migration law of areas with high water demand is highly consistent with the phenomenon of dryland converting to paddy in the same period. From 1990 to 2018, the matching degree of land and water resources in each growth period of crops decreased first and then increased. Most high-value areas of land and water resources matching are distributed in the interface between high-value areas of effective precipitation and dryland areas. It can be seen that natural precipitation is still the main source of water for cultivated crops. In recent years, the matching degree of land and water resources in the southern part of the Sanjiang Plain decreased obviously, and the unit yield of grain declined. It is suggested to reduce the quantities of dryland-to-paddy conversion projects in this area. At the same time, the matching level of land and water resources and the unit yield of grain in the western part of the Songnen Plain increased year by year, so the dryland-to-paddy conversion project can be carried out appropriately.