挠力河流域耕地水分盈亏时空变化特征及趋势模拟

为揭示挠力河流域耕地资源水分盈亏态势，以遥感影像、DEM数据和气象台站数据为基本信息源，基于遥感和GIS技术，对流域1990-2014年间耕地水分盈亏时空变化特征进行研究，并运用情景模拟技术模拟未来水分盈亏态势。结果表明：24 a间流域耕地面积增长放缓，1990-2002年水田急剧增加，旱地轻微上升，2002-2014年水田增长速度急剧下降，旱地面积减小；耕地水分盈亏程度变化明显，各等级耕地空间分布差异大，1990-2002年以中度和重度缺水变化为主，基本不存在严重缺水区，2002-2014年，轻度缺水区面积变化最大，重度缺水区缓慢下降。正常缺水是3期面积最大的缺水等级；模拟显示未来流域水分亏缺态势将更加严峻，高MPLD指数区分布更为集中，局部高水分亏缺区面积会进一步扩大，除轻度缺水区逐渐减少外，其余4种类型缺水区均保持增加，其中重度缺水区将大量增加。该研究结果可为挠力河流域农田灌溉方案的制定提供借鉴和参考。

Spatio-temporal characteristics of water budget due to the paddy field expansion in Naoli River Basin

Since early 1990s, the agricultural structure of Naoli River Basin, Liaoning Province, China has been greatly adjusted with a large amount of dry land changing into paddy field. This results in a set of inadequate problems in the utilization of water resources. To reveal the water profit and loss situation of the cultivated land resources in this river basin, so as to predominate the overall situation of water budget in Naoli River Basin and provide scientific basis for adjusting the layout of farmland, this paper established a water profit and loss degree evaluation model by using two indicators as the actual evapotranspiration (ET) and the farmland water requirements of the cultivated land in this basin to reflect the potential shortage of water budget and analyze the variation of area changes at different levels of moisture shortage. With this model, this sutdy discussed the water profit and loss situation of cultivated land resources in Naoli River Basin from 1990 to 2014 when the cultivated land constantly changed, and modelled the future scenarios by using the CA-Markov model. Data used in this study includes the remote sensing image data, the long-term sequenced meteorological data and the DEM data. Results show that the changes between the paddy field and the dry land in the Naoli River Basin were incredibly violent. The growth rate of cultivated land decreased gradually from 1990 to 2014, and the changing characteristics varied over time. From 1990 to 2002, the area of paddy field increased dramatically, and the dry land increased slightly; from 2002 to 2014, the growth rate of paddy field area showed significantly decrease trend and the total area of dry land decreased in a certain degree. The changes of the cultivated land's moisture profit and loss degree (MPLD) were obvious and the spatial variation of the profit and loss index evaluation grades was great, the change magnitude also changed in different periods. From 1990 to 2002, the farmland types were dominated by the moderate and serious moisture shortage in this river basin, and basically, there was no most serious moisture shortage farmland types. During the period from 2002 to 2014, area of mild moisture shortage changed the biggest, while the area of serious moisture shortage decreased slightly. Among them, the area proportion of farmland with normal water shortage was the biggest during these two periods. The simulation results show that the water deficit of the farmland in this river basin would be further intensified, the area that has higher grades of MPLD showed more centralized distribution, and partial high evaluated grades for the moisture shortage would expand in the future. Except for the slight increase of the farmland with mild moisture shortage, the area of the rest four evaluation grades farmland all kept increasing, and the area of serious moisture shortage evaluation grades increased intensely. These research results can be used as references and consultancies for the farmland irrigation schemes in the Naoli River Basin.