| Due to the rapid development of economy and society and the climate change,the drive of water cycle has changed into the artificial force,due to the accelerared increase of artificial water withdrawing,the farmland water cycle presents the dual characteristics of "natural-society".In recent years,in order to support human life and economy,the managers of irrigation areas focused on economic benefits while ignored the natural law and the sustainability of farmland,which caused groundwater over-pumoing and ecological environment deterioration and would threaten the high-quality agricultural production in the irrigated area.Thus,it is crucial to illustrate the health of farmland water-cycle for solve the above problems.This paper focuses on the health of farmland water-cycle in irrigated areas and selected Junliu Irrigated Area located in the North China Plain as the study area,where groundwater pumping and surface cannal irrigation both exist.The main results are as follows:(1)The healthy farmland water-cycle in multiple angles were illustrated,based on the systematic analysis on water-cycle paths and the summary of the previously related researches.In this study,a healthy farmland water cycle means the harmony of natural water cycle and the social water cycle,and the healthy sub-processes,that is,the water sources are diverse and reasonable,the quality and quantity of irrigation water are maintained,the water extraction and transmission are efficient and water-saving,the water consumption is efficient and high-yielding,the water withdrawal and drainage process is fast and the water quality is clean and less polluted.Based on this illustration,the comparing with similar concepts were analyzed.(2)According to the illustration of the farmland water-cycle process and its health concept,the evaluation index system of farmland water-cycle was determined by analytic hierarchy process(AHP),including 15 indexes in 4 dimensions.The judgement matrix was constructed to calculated the weight of each index and dimension layer.The healthy threshold of evaluation index system of farmland water-cycle was determined according to the relevant national standards and reference to the existing research.(3)The health status of farmland water-cycle in Junliu Irrigated Area from 2010 to2019 was evaluated basing on the evaluation system.The comprehensive results showed that the health condition of farmland water circulation in Junliu was "sick" from 2010 to2015 with no obvious change before 2013.Then it began to improve steadily from 2014.The health condition of farmland water cycle from 2015 to 2019 was upgraded to "normal".Dimension layer evaluation results showed that the health status of water source,water taking and transporting sub-processes and water consumption subprocesses had been significantly improved in recent years,while the health status of water withdrawal and drainage sub-processes had not been improved and basically remained "seriously ill".The index evaluation results showed that canal irrigation water leakage rate,water productivity,planting structure rationality index and farmland waterlogging prevention and drainage up to the standard were the best,which were basically in the "sub-health" or "healthy" state in recent years.The health status of irrigation water quality up to the standard,the piped level of field water transmission,the area ratio of highefficiency water-saving irrigation,the proportion of surface water and the diversity of water sources have been significantly improved.The evaluation results of the other six indicators were poor.According to the evaluation results,the corresponding reference suggestions were put forward for the construction and operation and maintenance management of the irrigated area.The research results can enrich the concept of regional healthy water cycle,provide reference for the health evaluation of farmland water-cycle in other regions,and provide decision-making basis for the sustainable development of water resources. |
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