Remote sensing monitoring on regional crop water productivity in the Haihe River Basin

Crop water productivity （CWP） agricultural development in water scarcity is one of the important indicators for sustainable area. There is serious conflict between water sup- ply and requirement in the Haihe River Basin. CWP of winter wheat and summer maize from 2003 to 2007 in the Haihe River Basin is estimated based on large-scale evapotranspiration （ET） and crop yield obtained by remote sensing technology. Spatial and temporal distribution of CWP of winter wheat and summer maize is investigated in this study. Results show that CWP of winter wheat in most parts of the study area varies from 1.02 kg/m3 to 1.53 kg/m3, and CWP of summer maize varies from 1.31 kg/m3 to 2.03 kg/m3. Multi-year averaged CWP of winter wheat and summer maize in the study area is about 1.19 kg/m3 and 1.59 kg/m3. CWP results show certain promotion potential to alleviate the water shortage in the Haihe River Basin. Correlation analysis of CWP, crop yield and ET shows that there is great potential for crop yield promotion without the growth in irrigation water. Large-scale CWP estimated by remote sensing technology in this study shows spatial distribution features, which could be used to real-time agricultural water resource management combined with crop yield and ET.     

秸秆覆盖下的夏玉米蒸散、水分利用效率和作物系数的变化

农业用水占华北水资源的70%以上,提高农业用水的效率对华北水资源安全具有重要意义。在节水农业研究中,利用农艺节水提高农田水分利用效率是节水农业的重要组成部分,其中减少农田无效棵间蒸发耗水和优化供水制度是主要的农艺节水措施。夏玉米是华北太行山山前平原的主要作物之一,一般在冬小麦收获前的5～7天套种在其中,以延长夏玉米的生育期。随着联合收割机的广泛应用,冬小麦收获后的秸秆直接覆盖夏玉米,对夏玉米的农田蒸散特别是苗期的蒸散产生影响;夏玉米生长在6～9月的雨季,一般年份降水能够满足夏玉米的需水要求,但夏季降水的分布变异较大,再加上近6年来的夏季干旱,使灌水对夏玉米的高产至关重要。为了提高夏玉米的农田水分利用效率,本研究的目的是建立秸秆覆盖下的夏玉米优化供水制度和研究秸秆覆盖对减少棵间无效耗水的影响及秸秆覆盖下的夏玉米作物系数的变化,为制定秸秆覆盖下的夏玉米优化供水制度提供依据。2年的实验结果显示,秸秆覆盖下的夏玉米产量在8000kg/ha,总蒸散量在390mm,水分利用效率在2.2kg/m3。干旱年份,夏玉米在灌四水的条件下产量最高,再增加灌水量,产量减少。水分利用效率随着灌水量的增加有所递减。     

冬小麦水分耗散特性与农业节水

本文根据中国科学院禹城综合试验站１９８６年－１９９６年蒸渗仪农田水分模拟试验资料统计；冬小麦全生育期耗水量可达４８２．５ｍｍ，缺水率可达６９．３％；冬小麦全生育不分耗散过程有两个明显的需水峰区和３个关键需水期，为实施节水灌溉提供了实验依据；冬小麦耗水量与环境因子有明显的相关关系，其统计规律可供地下水浅埋区区域灌溉预测参照应用。     

中国粮食生产的综合影响因素分析

采用模型模拟的方式, 根据中国社会发展规划, 将未来社会经济发展情景与区域气候模型、水资源模型和作物模型相连接, 综合评估和分析未来中国的粮食生产状况, 以期为宏观决策提供科学参考。结果表明, ①气候变化将影响未来三大作物单产, 如果不考虑 CO₂ 肥效作用, 未来雨养作物单产将受到更大冲击; 当灌溉条件保障后, 水稻受到冲击更大, 单产降低最多, 尤其是 A2 情景。如果考虑 CO₂ 肥效作用, 未来玉米平均单产变化不大, 小麦单产明显增加, 尤其是雨养小麦, 水稻单产也有所增加。②未来气候变化、水资源、社会经济发展将影响中国三大作物的需水量和农业供水量, 导致水稻、灌溉玉米和小麦的播种面积下降, 而雨养小麦和玉米的播种面积上升。③未来气候变化、 CO₂ 肥效、水资源和土地利用变化对粮食生产的影响较为复杂, 依情景和时段的不同而不同。农业可用水资源对粮食总产的影响最不利, 致使三大作物粮食总产量明显降低, 成为未来粮食生产的主要限制因素, 尤其是水稻生产; 土地利用对总产的负面影响最小; 气候变化和 CO₂ 的相互作用可使总量少许增加。未来各情景下水稻受到冲击最大, 而小麦和玉米则表现为不同程度的增产。     

近30年中国东北地区玉米种植体系的时空动态分析(英文)

Understanding crop patterns and their changes on regional scale is a critical requirement for projecting agro-ecosystem dynamics. However, tools and methods for mapping the distribution of crop area and yield are still lacking. Based on the cross-entropy theory, a spatial production allocation model(SPAM) has been developed for presenting spatio-temporal dynamics of maize cropping system in Northeast China during 1980–2010. The simulated results indicated that(1) maize sown area expanded northwards to 48°N before 2000, after that the increased sown area mainly occurred in the central and southern parts of Northeast China. Meanwhile, maize also expanded eastwards to 127°E and lower elevation(less than 100 m) as well as higher elevation(mainly distributed between 200 m and 350 m);(2) maize yield has been greatly promoted for most planted area of Northeast China, especially in the planted zone between 42°N and 48°N, while the yield increase was relatively homogeneous without obvious longitudinal variations for whole region;(3) maize planting density increased gradually to a moderately high level over the investigated period, which reflected the trend of aggregation of maize cultivation driven by market demand.     

Optimal spatial allocation of irrigation water under uncertainty using the bilayer nested optimisation algorithm and geospatial technology

The optimal spatial allocation of irrigation water under uncertainty has become a serious concern because of irrigation water shortage and uncertain factors that affect irrigation water allocation. In this study, an optimal multi-objective model for irrigation water allocation under uncertainty is developed to maximise the economic benefit of crops and minimise the operation cost and water deficit of crop irrigation. The original and optimal plantation structure, irrigation mode and soil water content are acquired through geospatial technology. A bilayer nested optimisation (BLNO) algorithm is designed to produce multiple individuals of design vectors using an ant colony neural network algorithm for an outer optimisation. Meanwhile, a continuous adaptive ant colony (CAAC) algorithm is used for inner optimisation to calculate the interval values of the uncertain model. The crop distribution and irrigation mode are obtained to parameterise the planting area and the water demand of each crop and each block in the multi-objective model. This model is then solved and analysed. Compared to the optimal schemes obtained from an inexact two-stage fuzzy-stochastic programming and the CAAC, respectively, BLNO can effectively and efficiently solve the optimal spatial allocation of irrigation water under uncertainty. This method can spatially maximise the economic benefit of crops and minimise the operation cost and water deficit of crop irrigation using lower and upper bound maps whilst visually obtaining the exact crop type, reasonable irrigation method and precise water demand for each block and for the entire irrigated area.     

荒漠绿洲区间作和密植对作物产量和水分利用效率的影响

针对间作种植模式下密植潜力薄弱、水资源不足、生产实践中难以同步提高产量和水分利用效率(WUE)的问题,在河西荒漠绿洲区通过大田试验研究了4个(5.25、6.00、6.75、7.50万株·hm^-2)玉米密度水平下玉米间作豌豆群体的产量和水分利用效率,以期为构建禾豆间作在密植条件下的高效节水技术提供理论依据。结果表明:玉米间作豌豆的土地当量比(LER)平均达到1.16,且LER随玉米密度的增大而增大。单位面积间作玉米的产量平均达到了相应单作的74.87%;随玉米密度的增大,作物产量的最大值均出现在高密度(6.75、7.50万株·hm^-2)处理中。间作0~120 cm土层平均土壤含水量平均低于单作玉米1.60%,但平均高于单作豌豆6.70%;两年内单作玉米和间作0~120 cm土层平均土壤含水量均在高密度(7.50万株·hm^-2)处理时最大。由于土壤贮水量、降雨量、灌水等诸多因素的影响,间作较单作增加了耗水量(ET),上述间作的ET比单作高19.23%~23.66%。与单作WUE加权平均相比较,间作的WUE分别高于单作11.08%、13.32%、18.86%和28.06%;不同玉米密度处理中,密度3(6.75万株·hm^-2)的WUE表现出了优势。因此,在河西荒漠绿洲区,同步提高作物产量和水分利用效率的有效措施之一是间作和密植条件。     

Rainfall Variability in Murang'a District, Kenya: Meteorological Data and Farmers' Perception

This study examines meteorological data and farmers' perception of rainfall in the Central Highlands of Kenya. Rainfall data from five meteorological stations during the period from 1947 to 1996 were analysed on an annual and a monthly basis. Daily data exist from 1957 and analyses from 1957 to 1996 were done on a daily basis. Discussions were held with 60 farmers about rainfall and its variation. Ten of these farmers were interviewed with a questionnaire about rainfall. Analysing annual precipitation and rain periods gave no clear trends over the study period. Results from analysing the growing seasons for maize, the main annual crop, and periods during which maize plants are sensitive to drought showed decreasing trends in rainfall amounts for the study period. Results from the interviews indicate that most of the farmers think rainfall has decreased over the last 40 years. Farmers'perceptions of rainfall are related to periods when the main food and annual crop require water and not to the periods scientists often analyse, i.e. annual and rain periods. More research and better advice from agricultural extension workers to farmers are necessary to enable this area to sustain itself in sufficient food production if the decreasing trends during the growing seasons and drought-sensitive periods continue.     

流动沙丘的改良利用与经济效益——以沙坡头地区为例

本文重点总结了我国在宁夏中卫腾格里沙漠中,平整流动沙丘引黄淤灌改良流沙地及在流沙地铺设隔水层的试验结果。试验表明,经引黄淤灌15年后,可沉积淤泥厚达22厘米。通过施肥、种植农林植物等措施,使原来单相流沙改良成为有层次的耕作土壤。经淤灌并加薄膜塑料隔水层后,所种植的农林作物增产效果显著,与对照相比,黄豆增产277.8%,玉米增产238.4%。一年生沙冬青苗高生长增加165%,地茎粗增加200%,二年生侧柏幼苗高生长增加163%,地茎粗增加79%。     

河北平原冬小麦播种面积收缩及由此节省的水资源量估算

以河北平原1998-2010 年11 地市的农业统计数据和22 个气象站点的逐日气温、降水量、水汽压、风速、日照时数和相对湿度等资料为基础,对该地区冬小麦播种面积的收缩情况及由此引发的耕作制度变化进行了分析;同时,结合作物系数法和逐旬有效降水量法,计算了不同耕作制度下的水分亏缺量,进而估算了该地区因耕作制度变化节省的水资源量。结果表明:① 该时段河北平原11 地市冬小麦的播种面积均呈收缩趋势,总面积下降了16.07%,约49.62×10⁴ hm²。京津唐城市群表现最为明显,下降了47.23%;② 冬小麦的降水满足率仅为20%~30%,而春玉米和夏玉米均为50%以上;冬小麦-夏玉米一年两熟制所需的灌溉水资源量为400~530 mm,而春玉米一年一熟制仅为160~210 mm;③ 该时段河北平原因冬小麦播种面积收缩而节省的灌溉水资源量约为15.96×10⁸ m³/a,相当于南水北调中线一期工程为京津冀三省市供水量的27.85%。     

鲁西北平原冬小麦耗水过程与节水灌溉管理模式讨论

本文利用禹城综合试验站土壤-植物-大气综合观测场冬小麦田间的小气候梯度仪和大型蒸渗仪的观测资料,结合作者建立的模拟SPAC系统中水、热、CO2通量和光合作用的综合模型,研究了冬小麦全生育期的耗水过程;根据模拟计算的土壤水分动态,对山东省鲁西北平原现行的灌水管理模式进行了讨论。(1)冬小麦全生育期耗水438mm;返青以前耗水占20%,拔节-灌浆期是耗水的旺盛时期,占67%;(2)灌水后地表以下1m处的渗漏量与土层前期储水量和灌水量有关,前期含水量越大,灌水量越大,损失越大,灌水利用率越低;(3)鲁西北平原现行的越冬水-返青水-灌浆水-黄熟水的灌水模式在各次的灌水量控制上应谨慎处理,否则会造成大量的水资源浪费,从而影响灌水利用率。     

民勤绿洲水资源利用中的问题与节水途径

石羊河进入民勤盆地的水资源逐年递减,导致绿洲内部地下水的过度超采,从而引起生态环境恶化及农田弃耕、沙化。缺水己严重地威胁着绿洲农业的发展。但是不合理的水资源管理制度、落后的灌溉方法和产业结构等使水资源的利用很不合理,灌溉水的利用率低下。改革目前的水资源管理办法,完善和配套渠系工程和田间工程,选用节水的优良作物品种,调整农业产业结构,推广应用先进的灌溉技术,逐步发展现代节水农业,建立节水型社会是民勤实施可持续发展战略的必由之路。     

Impact of the shrinking winter wheat sown area on agricultural water consumption in the Hebei Plain简

This study firstly analyzed the shrinkage of winter wheat and the changes of crop- ping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calcu- lated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are as follows. 1） The sown areas of winter wheat in the 11 cities in the Hebei Plain all shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×10^4 ha. The shrinkage was most serious in the Bei- jing-Tianjin-Tangshan metropolitan agglomerate, with a shrinkage rate of 47.23%. 2） The precipitation fill rate of winter wheat was only 20%-30%, while those of spring maize and summer maize both exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged only from 160 mm to 210 ram. 3） The water resources conserved as a result of the winter wheat sown area shrinkage during the study period were about 15.96×10^8 m^3/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Mid-Route of the South-to-North Water Diversion Project.     

绿城垦区历史时期农业灌溉渠系信息的遥感识别与提取

灌溉是干旱区农业时代社会经济发展必不可少的条件,人工渠系则可看做是灌溉农业最主要的水利设施,是干旱区农耕文明的主要特征和标志之一。绿城垦区是黑河流域下游古居延绿洲上历史时期最大的一块农业垦区,大量的房址、寺庙、灌溉渠系、耕地等反映过去人类农业活动的遗迹残留在垦区中的沙包和沙丘中。在查阅大量历史文献和考古资料的基础上,本研究结合高分辨率遥感影像和野外渠系样点的实地调查数据,依据农业灌溉渠系在遥感影像上表现出来的线性和纹理特征,人工数字化识别和提取了绿城垦区历史时期的农业灌溉渠系。研究结果表明,古居延绿洲上的绿城垦区在古代曾有过规模宏大的人工农业灌溉系统,保证了研究区历史时期繁荣人类农业活动的开展;此外,研究区古代的农业灌溉方式与中国干旱区现代的农业灌溉系统有着相似的灌溉思路。绿城垦区古代农业灌溉渠系在空间上的可视化精细分布是古绿洲历史时期繁荣人类农业活动的直接证据,对于研究古代的水利设施和区域环境变化也有重要的作用。     

基于DEM的地形湿度指数及其应用研究进展

地形湿度指数以数字高程模型（DEM）为基础,综合考虑了地形和土壤特性对土壤水分分布的影响,在流域土壤水分空间分布的研究中具有重要的理论与应用价值。根据对汇流面积时空变化的分析,地形湿度指数可分为静态、半动态和动态地形湿度指数等类型。在利用该指数评价土壤水分空间分布状况时,需要考虑计算方法与DEM网格单元大小的影响及其普遍适应性等问题。同时,针对黄土高原干旱半干旱区实际的水分循环过程和产流机制与现有地形湿度指数假设条件的差异,提出了地形湿度指数在黄土高原地区的研究设想与应用途径,以期为该区的水土保持和植被恢复研究提供理论和实践支持。     

作物需水量研究进展的回顾与展望

国内外有关作物需水研究的进展情况和相关估算方法,包括研究内容、定量估算方法和数学预测方法,通过其分析论述了各方法的主要原理、特点及局限性,并指出了日前作物需水研究领域存在的主要问题是在非均一下垫面条件下,植被与环境以及植被间的相互作用要比均一下垫面复杂得多。目前的计算模式存在着许多假设,普适性不够,难以推广应用,今后需进一步研究的课题与采取的研究思路主要是改进蒸散计算方法。最后简要介绍了一种利用遥感蒸散模型率定通用陆面模式CoLM来估算区域陆面蒸散量以及陆地耗水量的思路。     

Impacts of the local land-use system in a semi-arid region of northeastern China on soil properties, crop growth, and weed communities

We examined changes in soil properties, crop biomass, and weed communities in the Horqin Sandy Land of China to elucidate cropland degradation. We studied three local cropland types having periods of cultivation of up to 20 years: maize cropland on lowlands without irrigation (nonirrigated lowland), maize cropland on flat sandy lands with irrigation (irrigated flatland), and bean-centered cropland on sand dunes without irrigation (nonirrigated dunes). Soil properties and crop biomass were more degraded in nonirrigated lowland and nonirrigated dunes than in irrigated flatland. Weed communities in the nonirrigated croplands were the type that become established in drier conditions, whereas wetland weeds were more abundant on irrigated flatland. Trends of change in each indicator did not always occur in parallel and differed statistically among the cropland types. Monitoring these indicators within the context of local land-use systems can provide scientific evidence on which to base local management practices or recommendations for change.     

Impact of soil conditions on the physiological characteristics of maize plants in an arid region,Northwest China

Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures (sandy loam, sand) and three one-time irrigation volumes (60 mm, 20 mm, 0 mm) in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.     

人工牧草需水量的模拟计算及其有效性检验

 较高精度的模拟计算作物需水量对制定节水高效灌溉制度、灌溉排水规划和水资源合理配置至关重要。目前模拟计算作物需水量的主要方法有FAO-56双作物系数法、双涌源能量守恒模型、根系层水量平衡模型和SWAP模型。任何方法计算的作物需水量用于生产实践时,都应进行模拟结果的有效性检验。基于灌溉试验数据,应用联合国粮农组织推荐的FAO-56双作物系数法模拟计算了人工牧草——披碱草、冰草的需水量。并采用拟合相关图法、回归分析法和残差估计误差指示法对需水量模拟值进行了有效性检验。拟合相关图法给出统计相关趋势,属定性检验; 回归分析法和残差估计误差指示法给出了模拟值与实测值间的拟合优度和残差估计误差的范围,属定量检验。这种定性定量相结合的方法客观的检验了需水量模拟值与实测值的一致性,经有效性检验后的需水量模拟值可用于生产实践。     

Problems for water resources development in typical small karst drainage basins and countermeasures

IntroductionThe karate runoff produchon process is a hydrO-geological process dependent on the shape and bining ofrainfall hydropoh and the spatial vacation Pattern Of landfonns, which is represented by the peak-forestdepression and peak-forest pci ie. It is also affected by tile unique chacterishcs and spatial pattern ofsurface and underground channel netWork exiSted in the karshc catChmellt, where the surface drainagedivide is different from the underground dlainage divide. Along with rese…