水足迹框架下稻田水资源利用效率综合评价

为综合评价稻田水资源利用效率,优选高效灌排模式,本文基于水足迹理论,考虑水资源利用率、水资源产出效益和水量及环境效益3个方面,构建稻田水资源利用效率综合评价指标体系,利用层次分析法和模糊综合评价模型对2015—2018年各处理稻田水资源利用效率进行综合评价,并与单个指标的评价进行对比。结果显示:各处理作物水足迹年均值分别为976.8(浅水勤灌)、1008.7(浅湿灌溉)、954.4(控制灌溉)和792.6 mm(蓄水-控灌),蓝、绿及灰水比例年均值分别为16.4%、40.9%和42.7%;水资源产出效益在水资源利用效率评价中占据首要位置;各处理稻田水资源利效率综合评分值在2.8058～3.9432之间,等级为中或中高,优选出的高效灌排模式为蓄水控灌;作物水分利用效率、作物水足迹与综合评价的对比表明水资源利用效率综合评价至关重要。基于水足迹的稻田水资源利用效率评价能够为农业用水效率评价提供一种新视角,为农业节水尤其是水稻节水的科学研究和决策提供实践依据。     

山西省“蓝水”“绿水”资源时序变化分析

1955年Falkenmark首次提出蓝水和绿水概念。为研究山西省水资源时序变化情况,总结山西省年度降水分布规律,将蓝水、绿水与农业相结合,分析计算山西省广义农业用水中耕地灌溉用水蓝水和耕地有效降水绿水数据。发现绿水资源与降水呈正相关,蓝水资源也随之增多。除此之外,耕地有效降水绿水与耕地径流量、耕地深层渗漏量、气候变化、土地利用有一定关系。在此基础上进行数据分析和预测,提出今后农业用水研究方向和水资源合理配置的建议。     

基于水足迹的宁夏平原农作物生产用水分析

引入水足迹的概念和计算方法,对宁夏平原农作物生产用水状况进行分析,结合农业发展规划,对种植结构调整后的农业用水量和用水效率进行了分析.结果表明:2004年宁夏平原农作物生产用水总量为26.28亿m3,被作物有效吸收利用的引黄灌溉水量为22.37亿m3,占农作物生产用水总量的85.14%;由降水形成的土壤"绿水"利用效率为14.86%,"绿水"利用量远小于灌溉"蓝水"利用量;种植结构调整可减少区域农作物生产用水总量,使"蓝水"利用效率提高、"绿水"利用效率下降,还可促进区域粮食水分生产率的提高.     

赣江流域蓝水绿水资源时空变化分析

在当今的水资源管理中,分析评估气候变化下流域内蓝水、绿水资源的时空变化情形,能为维持生态系统稳定、保障社会经济的发展提供依据.本文利用SWAT模型模拟了赣江流域1960～2013年的水文循环过程,基于趋势分析、Mann-Kendall检验等方法,分析了流域内蓝水及绿水资源的时空变化情况.在空间上看,赣江流域内蓝水及绿水资源多呈上升趋势,只有流域西部、中部少数地区绿水流和蓝水流有下降的倾向,绿水储量在整个流域内都呈现出了显著的上升趋势(P<0.05).在整个流域尺度上,蓝水与绿水资源在过去50年间都呈现出上升趋势,蓝水流、绿水流、绿水储量的变化倾向率分别为11.3mm/10a、4.87mm/10a、16.4mm/10a,其中绿水流、绿水储量自20个世纪90年代后的上升趋势非常显著(P<0.05),而蓝水流则在最近20年间呈现出略微的下降趋势,在未来规划管理中应考虑人类活动取用水对水资源量的影响.     

基于SWAT模型的东江流域蓝水、绿水时空分布特征研究

基于SWAT(soil and water assessment tool)模型,对东江流域天然状态下的降雨径流过程进行模拟,进而评估流域蓝水、绿水的时空分布特征。结果表明:东江流域蓝水、绿水资源量都非常丰富,多年平均蓝水资源量274.67×108m3,绿水资源量178.72×108m3(主要以绿水流为主),蓝水资源是绿水资源的1.54倍。东江流域以蓝水为主的水资源构成体系主要是由流域湿热多雨的气候条件决定的。从时间变化来看,近年来东江流域蓝水资源、绿水资源、绿水流、绿水储皆无显著增加或降低趋势。从空间分布上来看,蓝水资源格局主要受降雨格局控制,而绿水资源不但受气候条件影响,还受流域下垫面的自然属性以及人类活动干扰,如土地利用方式、土壤类型等,分布格局较为复杂。     

基于GLDAS-NOAH的长江流域蓝绿水资源时空变化特征

基于GLDAS-Noah水文模型,模拟长江流域蓝绿水资源量,并揭示其时空变化特征。结果表明:2000—2019年长江流域多年平均蓝水资源和绿水资源分别为420.24 mm和686.95 mm,绿水资源约是蓝水资源的1.62倍。近20 a来长江流域蓝水资源、绿水资源和绿水系数呈不显著增加趋势,2000—2019年蓝水资源与绿水资源变化速率分别为3.26 mm/a 和2.27 mm/a。从年内分配上看,蓝绿水资源在7—8月份较多,占全年的29%~32%;在1 —2月份较少,占全年的5%~6%。从空间分布来看,蓝水资源呈现东南高西北低的分布格局,绿水资源呈现东高西低的分布格局,而绿水系数呈现西北高东南低的分布格局。科学全面评价蓝绿水资源可以为优化水资源利用模式、提高水资源利用效率提供科学依据。     

太行山区蓝水绿水沿垂直带演变规律及其归因分析

以太行山区(华北平原水源地,分属黄河流域和海河流域)为研究对象,建立了分布式水文模型WEP-L(Water and Energy transfer Processes in Large river basins),模拟了1980-2000年间山区的水循环过程,总结了蓝水(径流性水资源)和绿水的年际及随高程的变化规律。在此基础上,定量区分了研究区气候波动和土地利用/覆盖变化对蓝水与绿水变化的贡献。研究结果表明:(1)太行山两侧的蓝绿水变化具有明显的差异;海河片区蓝水呈增长趋势,绿水呈下降趋势;黄河片区蓝水呈减少趋势,绿水呈增长趋势。(2)太行山区蓝水资源量变化的主导因素是气候波动。(3)土地利用/覆盖的改变是太行山区绿水变化的决定性因素。植被增多可增加绿水资源的利用,但同时将明显减少对经济社会发展非常重要的蓝水资源量。因此,山区国土资源开发与空间优化须重点考虑蓝水和绿水的合理调控。     

喀斯特石漠化典型区蓝水绿水转化模拟

由渗漏导致的降水大量流失是造成喀斯特石漠化地区地表水短缺的主要原因,将渗漏的难利用蓝水转化为可供植被生长利用的生态绿水是目前技术条件下提高水资源利用量的有益探索。基于蓝水绿水理论和土壤-植物-大气连续体(SPAC)原理,通过采用EcoHAT系统水循环模型模拟贵阳市非城镇地区的蓝水绿水转化,发现:(1)研究区绿水占降水的份额不到50%,远低于全球65%的平均水平,具有很大的转化利用潜力;(2)增加植被覆盖度和增厚土层均能实现将渗漏蓝水转化为生态绿水,增厚土层的转化效果更为显著;(3)增加植被覆盖度对减少渗漏的转化作用存在一个明显的阈值,当植被覆盖度增长到56%左右时,其减少渗漏的作用急遽减弱。鉴于研究区石漠化的典型性,本研究对类似地区提高水资源利用量具有一定参考意义。     

基于SWAT的北江流域蓝绿水评估及其干旱响应

为探究北江流域的水资源状况及其在不同程度干旱下的变化特征,利用SWAT模型模拟北江流域径流过程,并在此基础上评估北江流域的蓝绿水资源时空变化及其对干旱的响应特征.研究表明:北江流域水资源以蓝水为主,多年平均蓝水量为1149.08 mm,绿水量为981.08 mm,绿水系数为0.48;1966-2010年间,北江流域蓝绿...     

基于生态水文学原理的水资源评价方法

鉴于目前的水资源评价多集中于可见的、可以被直接利用的水资源,忽视了土壤水资源的评价和管理,根据生态水文学原理,把降雨划分为绿水和蓝水,从水循环的全过程和水量平衡的全要素来看,把"绿水"引入水资源的范畴中,作为广义水资源的一部分,把降水看作水资源的总来源。     

Temporal Variability of Water Footprint for Maize Production: The Case of Beijing from 1978 to 2008

The water footprint (WF) of crop production is a comprehensive indicator that can reflect water consumption types, quantities and environmental impacts during the crop growth period. This study assesses interannual variability of green, blue and grey WFs of maize production in Beijing from 1978 to 2008. Results indicate that: (1) The multi-year average WF of maize was 1,031 m³ ton^?1 which was 56 % green, 25 % blue, and 19 % grey; (2) the climate experienced a warm-dry period in Beijing during the period from 1978 to 2008, and this lead to the increase of crop water requirement and irrigation water requirement for maize with trends of 0.52 mm a^?1 and 2.86 mm a^?1, respectively; (3) under the combined effects of climate change and agricultural inputs, the total WF and green WF presented decreasing trends. The blue and grey WFs had clear increasing trends; (4) statistical analysis revealed that interannual variability of green and blue WFs were caused by both climatic factors (effective precipitation) and non-climatic (agricultural inputs) factors. The grey WF was mainly associated with non-climatic factors, such as chemical fertilizers consumption.     

Quantifying the Poorly Known Role of Groundwater in Agriculture: the Case of Cyprus

Agriculture in the Mediterranean region is constrained by limited water resources and in many countries irrigation demand exceeds the renewable water supply. This paper presents a comprehensive approach to (a) quantify the consumptive green (soil moisture provided by precipitation) and blue (irrigation) water use for crop production, (b) distinguish the contribution of groundwater to irrigation supply and (c) estimate groundwater over-abstraction. A spatiotemporally explicit soil water balance model, based on the FAO-56 dual crop coefficient approach, which includes the computation of evaporation losses of the different irrigation systems, was applied to the 5,760-km² area of the Republic of Cyprus for the agro-meteorological years 1995–2009. The model uses national agricultural statistics, community-level data from the agricultural census and daily data from 34 meteorological stations and 70 precipitation gauges. Groundwater over-abstraction is quantified per groundwater body, based on the sustainable abstraction rates specified in the Cyprus River Basin Management Plan, as prepared for the EU Water Framework Directive. It was found that, on average, total agricultural water use was 506 Mm³/year, of which 62 % is attributed to green water use and 38 % to blue water use. Groundwater contributed, on average, 81 % (151 Mm³/year) to blue water use and exceeded the recommended abstraction rates by 45 % (47 Mm³/year). Even though the irrigated area decreased by 18 % during the 2008 drought year, relative to the wettest year (2003), total blue water use decreased by only 1 %. The limited surface water supply during the driest year resulted in a 37 % increase in groundwater use, relative to the wettest year, and exceeded the sustainable abstraction rate by 53 % (55 Mm³/year). Overall, the model provides objective and quantitative outcomes that can potentially contribute to the improvement of water resource management in Mediterranean environments, in the light of climate change and expected policy reforms.     

辽宁省春玉米生产水足迹的时空变化研究

为降低农业生产活动中农作物对水资源的高消耗,提高用水效率,借助辽宁省1987—2018年19个气象站点逐日气象数据及春玉米产量数据,全面计算绿水足迹、蓝水足迹及灰水足迹的真实消耗。结果表明：（1）辽宁省春玉米生产水足迹自2002年起变化幅度不明显,多年平均值是1424.21 m³/t,其中绿水足迹占54%,灰水足迹占27%,蓝水足迹占19%。（2）从绿水足迹看,辽宁省春玉米绿水足迹每年以6.28 m³/t速率减少,空间分布上2002年绿水足迹高值区主要集中在东部地区;2010年辽宁省整体绿水足迹较高。（3）从蓝水足迹看,每年以1.06 m³/t的速率增长;2002年辽宁春玉米蓝水足迹高值区主要分布在环渤海、宽甸及其周围地区;2010年,辽宁省大部分地区蓝水足迹较低。（4）灰水足迹整体以每年14.03 m³/t的速率降低,主要与农作物产量及氮肥施用量相关。     

Green, Blue and Grey Water Footprints of Primary Crops Production in Nepal

This study aims to estimate the green, blue and grey water footprints (WFs) of nine primary crops production in 75 districts, 5 developmental regions and 3 physiographic divisions of Nepal using local meteorological, agronomical and irrigation data at high spatial resolution. The estimates are based on the framework prescribed by the guideline of the Water Footprint Network. The green and blue WFs are calculated using a water balance model whereas the grey WF is estimated as the volume of freshwater needed to dilute nitrate pollution to an acceptable level. WF varies across different crops considered, different districts, development regions and physiographic divisions. WF of potato and wheat in Nepal is comparable to the world average; but paddy, barley and pulses have higher while sugarcane and maize have lower values compared to the world average. WFs of paddy, maize, potato and wheat are lower in Terai than the Hills and Mountains due to the accessibility of irrigation system and higher crop yield. Millet, pulses, oilseeds and barley have lower WFs and are suitable for Mountains. Similarly, sugarcane is suitable for both Terai and Mountain divisions because of its lower WF. Crops in Far Western Development Region generally have higher WFs due to the low crop productivity, and higher fertilizer use.     

京津冀地区主要农作物生产水足迹研究

利用京津冀地区(2个直辖市、11个地级市)气象及农业基础数据,采用彭曼公式与CROPWAT软件相结合的计算方法,分析了2014年京津冀地区主要农作物的生产水足迹。结果表明:小麦在整个生长期需水量主要以蓝水足迹为主,玉米在整个生长期主要以绿水足迹为主;2014年京津冀地区主要农作物总的生产水足迹为437.03×108m3,其中绿水足迹为137.71×108m3,蓝水足迹为176.03×108m3,灰水足迹为123.30×108m3;从京津冀地区主要农作物总的生产水足迹空间格局上来看,沧州、保定、邯郸和石家庄地区的主要农作物生产水足迹较大,是水资源调控的主要地区。     

Water Footprint of Grain Product in Irrigated Farmland of China

China faces the dual challenge of grain production pressure and water scarcity. It is significant to reduce water footprint of grain product (WFGP, m³/t) in irrigated farmland. The focus of grain production and agricultural water use, and the precondition is to determine the WFGP and its composition. This paper estimates the WFGP in irrigated farmland of 31 provinces (including municipalities, autonomous regions) a by collecting actual data of 443 typical irrigation districts in 1998, 2005 and 2010, and analyses its temporal and spatial variation in irrigated farmland of China. The result shows that the WFGP in each province decreases with time except in Jiangxi and Hunan, and the average value of all provinces reduced from 1494 m³/t in 1998 to 1243 m³/t in 2010. The WFGP decreases faster in more developed municipal cities and major grain production provinces. The annual average WFGP in irrigated farmland is 1339 m³/t and the blue and green water account for 63.5 % and 36.5 % of the total, respectively. The WFGP and its composition are significantly different between provinces. Generally, provinces distributed inside and beyond Huang-Huai-Hai Plain, have a higher water productivity, lower WFGP and blue water footprint of grain product, while most provinces located in northwest, northeast, southeast and south China have a higher WFGP and lower proportion of green water in the WFGP as a whole. Portion of the blue water footprint (BWFGP) is not consumed for crop evapotranspiration (BWFGP _ET ) but conveyance loss (BWFGP _cl ). The national averaged BWFGP _cl decreases with time and but still remains up to 466 m³/t in 2010, making up 34.8 % of the WFGP. In order to safeguard grain security and ease the water resource pressure, the Chinese government should increase investment and apply advanced technology for developing water-saving agriculture, improve the efficiency of water use and further reduce the WFGP. Considering also the contribution of grain output and the relatively high WFGP, the government should give priority to developing water-saving agriculture in the Northeast of China.     

Dissolved organic matter from agricultural fields in the irrigation period.

The aim of this study was to quantify and characterize the dissolved organic carbon (DOC) of paddy fields and crop fields in Tottori, Japan. Dissolved organic carbon (DOC) and ultraviolet (UV) absorbance was measured for the filtrated water of each samples. DOC concentration and SUVA (specific UV absorbance) of biodegradation analysis samples were determined around 50 days after the incubation. In the Fukui paddy fields, DOC concentration varied seasonally from 1.1 to 10.1 mg.Cl(-1), showing higher concentration in heavy runoff of non-agriculture period in April. However, DOC concentration variation did not always correspond to rainfall. The Obadake paddy fields also showed a similar pattern with Fukui paddy fields. The daily DOC discharge per area in Fukui (up), Fukui (down), Obadake (south), Obadake (north) paddy fields influent from paddy fields were 0.02, 0.0161, 0.0135 and 0.0027 kg.a(-1).day(-1), respectively. These differences resulted from differences in agricultural types and customs of farmers according to paddy fields and fields. Also, SUVA (an indirect means to evaluate humic substances (hydrophobic fraction)) of the studied influent waters from paddy fields were generally lower than the influent waters from crop fields. The non-biodegradable DOC accounted for 50.2-98%, 46.8-85.5% of the total DOC in the paddy fields and crop fields.     

Evaluation of a small basin water-harvesting system in the arid region of Jordan

The performance of a small runoff-basin water-harvesting system (negarim) was evaluated under a typical Mediterranean arid environment in Jordan. Rainfall, runoff, catchment area, soil water storage, and crop evapotranspiration were analyzed as elements of one system. Three micro-catchment areas (25, 50, and 75 m²) and three surface treatment methods (natural, plastic cover, and compaction) were used. Runoff efficiency was evaluated for 16 storms. Storage efficiency was evaluated for eight periods by monitoring soil water balance in the crop root zone. The overall efficiency of the water-harvesting system was determined as the ratio of the amount of water stored and used by the crop to the amount of rainfall received in the catchment area. The overall efficiency of the system varied from over 85% to as low as 7% depending on the size of the catchment and the root zone capacity. Gains in runoff improvement were lost when the soil moisture in the cultivated area was near field capacity. The required ratio of the catchment area to the cultivated area was found to be strongly related to the root zone storage capacity and the rate of consumptive use as well as rainfall-runoff characteristics.     

Optimal Allocation of Agricultural Water Resources Based on Virtual Water Subdivision in Shiyang River Basin

Without subdividing into blue and green virtual water, the virtual crop water is currently used in the allocation of water resources based on virtual water strategy. In order to improve agricultural water use efficiency and the proportion of green water utilization, a multi-objective optimal allocation model for agricultural water resources is developed in this study. The model is based on the subdivision of virtual water into blue and green virtual water, subject to three objectives of the maximum net benefit from agriculture, the minimum fairness difference in the utilization of water, and the maximum proportion of green water utilization. Taking Shiyang River basin as an example, agricultural water resources are optimized through regional virtual water trade in the basin. Results show that compared with the situation in the year 2007, the net benefit of agriculture, the fairness difference in the utilization of water, and the proportion of green water utilization are optimized. At the same time, the planting ratio of food crops, such as corn, reduces, while the planting ratio of cash crops, such as cotton, vegetables, and fruits, increases. Through regional virtual water strategy in the basin, with the crops of different districts having comparative advantages, the proportion of green water utilization and the blue water use efficiency are improved. The study provides a scientific basis to solve the water shortage problem in the basin.