作物需水量与灌溉制度模拟

从作物需水量的基本概念出发，以水量平衡原理为基础，建立了模拟农田根层土壤水循环的计算机模型-ISAREG.这一模型具有多种功能，可模拟根层土壤水分变化，评价给定的灌溉制度，计算作物需水量和灌溉需水量，也可用以制订多种供水限制条件下的优化灌溉制度．用望都灌溉试验站的小麦、玉米、棉花3种作物两年的试验观测资料对上述模型进行了验证．     

气候变化背景下华北平原灌溉需水及农业干旱易发区变化研究

以华北平原为研究区,选取冬小麦和夏玉米作为典型作物,采用作物系数法并依据预估的气候情景计算典型作物的净灌溉需水量,分析不同气温和降水变化幅度下冬小麦和夏玉米需水过程和需水总量。同时,结合气象干旱和需水异常程度划分了干旱易发区。所得成果可供相关研究人员参考。     

淮北平原基于水文气象多因子的土壤水分动态预测

为研究土壤水分动态变化,利用五道沟水文实验站1989-2015年水文气象和大田土壤水实测资料,采用灰色关联度和线性回归分析,建立了冬小麦各生长阶段不同土层土壤水分预测模型。结果表明:不同土层土壤水分与气象因子的关联度一致;不同生长阶段土壤水分与气温和地下水埋深关联度最强,分别达0. 92和0. 95;分蘖-越冬期,土壤水分与地下水埋深和日照时数关联度最强,其他生长阶段,土壤水分与气温和地下水埋深关联度最强。通过水文气象因子模拟土壤水分拟合度较高,R~2达0. 94。不同生长阶段不同土层,土壤水分计算模型均具有良好的预测能力,R~2达0. 80。成果为实施作物不同生长阶段的灌溉计划提供科学依据。     

气象因子和土壤水分变化对河北省夏玉米产量的影响

利用国家农业气象站河北省10个站点2001年-2010年的农业气象、夏玉米产量和农田土壤湿度等资料,采用线性回归分析等方法,研究了河北省夏玉米产量与降水量、积温及土壤湿度之间的关系。结果表明:多数站点夏玉米产量与降水量、积温、土壤相对湿度呈正相关关系。在夏玉米生长季节内当降水总量为250～450mm、积温大于2 200℃、土壤相对湿度大于田间持水量的70%时,河北省玉米产量可达其最高产量的70%以上。若降水量低于250mm,需通过灌溉补充土壤水分,以保障玉米产量。     

黑龙港地区的农业干旱风险评估

干旱是黑龙港地区最严重的农业气象灾害,评估冬小麦各生育阶段的干旱风险可为合理制定灌溉制度、采取相应的防旱抗旱措施提供依据。基于验证后的APSIM模型所模拟的1961年-2005年31个点的土壤含水量动态,计算得到了冬小麦各生育期的土壤相对湿度干旱指数,分析了农民方案和优化方案的该地区的农业干旱时空分布特征。结果表明,干旱频率发生较高的时期农民方案中是播种-越冬期和返青-拔节期,分别为48.89%和27.60%;基于"吴桥模式"的优化方案是越冬-返青期、返青-拔节期和灌浆-收获期,干旱发生的频率为51.61%、39.78%和62.22%。易发生干旱的地方多位于邢台、衡水南部和邯郸北部。在冬小麦各生育阶段,干旱指数年际变化显示出两种方案的变化趋势基本一致。尽管总体说来优化方案发生干旱的风险要高于农民方案的,但基于"吴桥模式"的优化方案充分发挥了根系带的土体水库功能,减少了灌溉水,能够高效利用土壤水,如果全区31个点在1961年-2005年间,均按照优化方案灌溉,相比农民方案总共可节水61 785mm,表明"吴桥模式"可在黑龙港地区推广,它在一定程度上可规避干旱风险,同时能达到节水、稳产的目标。     

东北三省典型气象灾害对粮食生产影响特征研究

基于改进后的Mann-Kendall趋势检验方法(MMK)对东北三省1949—2015年各省主要作物种植时序变化特征进行研究。利用1949—2015年该地区典型气象灾害(干旱、洪涝、低温、风雹、台风)的受灾、成灾及绝收面积构建对应灾害类型的灾害减产成数,并利用趋势分析、脱钩关系评价模型评价识别各类灾害对东北三省粮食生产的影响特征。研究结果表明:1949—2015年东北三省粮食作物种植面积比例降低趋势显著,典型作物产量由高到低为:玉米、稻谷、小麦及大豆,且四种作物产量均呈增加趋势。东北三省受灾害影响程度由高到低分别为:旱灾、洪涝、风雹、低温及台风。粮食种植面积和粮食产量与典型气象灾害间的脱钩关系相似,2000年以来东北三省旱灾和洪涝灾害与种植面积间以绝对脱钩关系为主。     

The Status and Trend of Water Pollution Control Technology in China

ABSTRACT

The feasibility of predicting total summer crop water use by grassland, based on early or pre-season soil moisture reserves, was investigated. Tests were based on the correlation over time between simulated soil moisture and related variables at six South African climate stations. A weather driven computer budget model was used to simulate daily soil moisture reserves. Results indicate that early prediction of seasonal crop water use is not feasible, but that deep soil moisture is stable enough over time to be a reliable monitoring variable for crop growing conditions. Moisture stored in the deep soil has good potential for monitoring more severe drought conditions.     

黏弹性人工边界地震动输入方法及实现

本文对实现黏弹性边界的常用方法进行了总结,对相应于黏弹性边界的地震动输入公式进行了详细推导,把自由场应力的求解也转化为自由场速度的求解,简化了地震动输入公式,并给出了地震动输入的简化方法。基于ABAQUS软件,进行算例分析并和理论解进行对比,验证了各种黏弹性边界实现方式及本文地震动输入方法的合理性和正确性。最后,对大朝山重力坝典型挡水坝段进行地震响应分析,通过施加黏弹性边界并输入相应地震动,评价了无限地基辐射阻尼的影响,并与无质量地基模型的计算结果进行了比较。结果表明,考虑辐射阻尼效应后坝体地震响应明显降低,故在实际工程抗震分析时对其影响应予以适当考虑。     

Comparison of soil moisture at different depths for drought monitoring based on improved soil moisture anomaly percentage index

To better understand the characteristics and mechanisms of droughts at different drought stages, this study selected the Xiangjiang River Basin in China as the study area, and evaluated soil moisture (SM) at different depths for drought monitoring, through SM data simulated with the variable infiltration capacity (VIC) model. To solve the problem of unreasonable drought/wetness classifications based on the soil moisture anomaly percentage index (SMAPI), an improved soil moisture anomaly percentage index (ISMAPI) was developed by introducing the Box–Cox transformation. The drought/wetness frequency generated by ISMAPI demonstrated preferable spatial comparability in comparison with those from SMAPI. The lag time of ISMAPI relative to the standardized precipitation evapotranspiration index was closely related to soil depth, and was characterized by a fast response in shallow soil layers and a relatively slow response in deep soil layers. SM in shallow soil layers provided a measure for monitoring short-term droughts, whereas SM in deep soil layers provided a better measure for long-term persistent drought events. Furthermore, the occurrence and mitigation time of drought events identified by SM in deep soil layers usually lagged behind that identified by SM in shallow soil layers. Compared with deep SM, SM in shallow soil layers responded faster to meteorological anomalies, thereby resulting in shorter periods of SM persistence in shallow soil layers than in deep soil layers. This can explain the differences of SM at different depths in drought monitoring.     

黄河流域农业干旱特征研究

本文以作物根系层土壤含水率为基础建立了作物干旱指标模型，并综合考虑作物不同生育阶段水分条件对作物的影响，引进敏感系数，建立了干旱等级模型，研究了黄河流域干旱的地域性，季节性，持续性等特征，并对黄河流域区域干旱进行了分析。     

河北省夏玉米生育期气象要素变化特征及相关性

为深入探究气象要素与夏玉米产量的关系, 根据逐日气象数据、逐年作物数据, 采用气候倾向率、M2K 突变检验及相关性检验等方法对河北省夏玉米气象产量及相关气象要素变化特征进行分析, 在此基础上探讨两者相关性 及作用程度。结果显示: 河北省平均、最高、最低气温呈显著上升趋势, 日照时数、降水量、相对湿度、风速则呈显著下降趋势; 1960- 2017 年河北省夏玉米气象产量以每 10 年- 568 kg/ hm2 速度显著减少; 气象产量与平均气温、最 高气温、最低气温负相关, 与日照时数、降水量、相对湿度、风速正相关; 降水量、最低气温、风速是影响河北省夏玉米气象产量的关键气象要素, 最高气温和日照时数对夏玉米气象产量影响较小。研究成果可为优化农业资源结构, 促进地区农业可持续发展提供理论支撑。     

An Empirical Assessment of On-Farm Water Productivity using Groundwater in a Semi-Arid Indian Watershed

Realistic estimation of irrigation volume applied to any crop at farm level generally requires information on event based discharge rates and corresponding periods of irrigation application. Use of mean seasonal discharge rates leads to erroneous estimation of volume due to unaccounted seasonal fluctuations in the water table, upon which the discharge rate of tube well is dependent. In the absence of such information, an alternative approach of estimating farm level water application based upon water table fluctuation data has been adopted in this study. The total actual water extracted during each irrigation event from the watershed was distributed among the farms irrigating crops in proportion to the product of irrigation time and the pump capacity (h_p). Volume of water withdrawal concurrent to an irrigation event was computed based on the water level fluctuations in the wells in conjunction with potential recharge contribution from the surface storage structures to the groundwater aquifer. A production function approach was used to estimate the marginal productivity of water for selected crops at various stages of plant growth. Water, as an input in the production function, encompassed either in-situ soil moisture storage from rainfall or irrigation from groundwater or both. The inter-season as well as intra-season groundwater use, and the consequent groundwater withdrawals were analyzed based on the marginal value and output elasticity of water at different crop growth stages during the season. The cotton crop realized marginal value product of water, ranging from Rs. 1.03/m³ to Rs. 10.43/m³ at different crop growth stages in cotton. Castor crop had the marginal value product ranging from Rs. 2.89/m³ to Rs. 6.81/m³. The availability and use of water, including soil moisture, in the two seasons, coupled with the local harvest prices received, yielded the differential marginal values of water.     

宽垄沟灌对夏玉米生育进程及产量的影响

通过2013～2015年3年的大田试验,研究了宽垄沟灌和传统种植模式对夏玉米生育进程及产量的影响.结果表明:不同种植方式下,水分胁迫均对作物的生育进程有影响,夏玉米生育周期随着水分处理的增大而延长;与常规种植方式相比,宽垄沟灌方式下,夏玉米的生育周期延长了1～4d.过低或过高的水分胁迫均会抑制作物的正常生长,导致灌浆速度缓慢,适当水分处理(L-70)能有效促进籽粒增长,达到节水高产的效益.2013～ 2015年夏玉米的产量及其构成因子基本上都随着灌水量的提高而增加,较常规种植,宽垄沟灌方式下夏玉米平均增产率为2.38％～6.04％.说明宽垄沟灌能有效改善夏玉米穗部性状,促进籽粒灌浆,达到夏玉米节水高产的目标.     

Optimizing Approach of Water Allocation to Off-Takes During Reduced Flows

Multi-objective optimization models with an index were developed based on farmers’ preferences, local requirements, supplies available at the head of the canal, system losses, crop demand about different growth stages, and field soil moisture balance. The models were applied using linear programming. The Model 1 determines the cropping pattern by maximizing net economic benefits using a monthly basis lumped volume available at the head of the canal and is set to the minimum and maximum area constraints along with the constraint of minimum main crop area. The areas for different crops given by the first model form input for the Model 2. The other inputs of Model 2 included periodic supply available at the head of the primary canal (7-day period in this study), root growth depth, demand, and soil moisture constants. The Model 2 optimizes the sum of relative yields of all the crops and provide the irrigation levels of various crops for specified periods. Finally, the distributed area and irrigation levels determined by Model 2 are used in conjunction with the losses to decide flow rates of off takes. The complete program was implemented in the West branch irrigated area of Mirpurkhas subdivision. The results showed that the resources were allocated to off-takes in a competitive and conflict-free manner.

     

调亏灌溉不同灌水量对玉米生长和产量的影响

为了探究调亏灌溉对玉米生长的影响,设计了玉米不同生育期亏水试验。试验结果表明,拔节-孕穗期复水后玉米株高生长速度最快,进行亏水处理对玉米根系有显著抑制作用。玉米不同生育期的水分亏缺对玉米株高和产量的影响程度排序分别为:拔节-孕穗期>三叶-拔节期>孕穗-灌浆期>灌浆-成熟期。在三叶-拔节期进行适宜程度的亏水处理可以明显提高灌溉水利用率,玉米不但不会减产,反而能提高玉米产量性状。该研究为寻找作物高产、节水的技术方法打下基础。     

Fuzzy Stress-based Modeling for Probabilistic Irrigation Planning Using Copula-NSPSO

Hydrological uncertainties are the main components of a sustainable framework in agricultural water management. Prediction of drought as a meteorological phenomenon should be considered to define the groundwater exploitation strategies. This study was conducted to develop a multiobjective-bivariate structure for reducing the soil moisture deficit and groundwater withdrawal in the Qazvin Irrigation District, Qazvin province, Iran. Therefore, non-dominated sorting theory, self-organizing particle swarm optimization and bivariate copula functions were incorporated under fuzzy uncertainty analysis. The results showed that the generalized extreme values and log-normal distribution functions had the best fitness on the drought peak and severity with Kolmogorov Smirnov amounts of 0.08 and 0.17, respectively. Furthermore, the goodness-of-fit tests were indicated the Joe joint function (MLE = 11) is the appropriate function for estimating the probabilistic values of drought characteristics. Proposed plans were to increase the water use efficiency for improving the expected yield production by an average of 20%. Furthermore, the standardized groundwater index was decreased from 1.1 to –4.3 for winter crops.

     

基于SAPEI的河北省玉米生育期旱涝演变特征

为探究河北省玉米生育期旱涝演变特征,通过构建标准化前期降水蒸散指数(standardized antecedent precipitation evapotranspiration index,SAPEI)和利用气象站点逐日气象数据,对河北省1980—2020年玉米生育期内旱涝特征演变进行时空分析。结果显示：1980—2020年河北省SAPEI在玉米初始生长期、快速发育期、发育中期和成熟期4个生育阶段内波动变化区间为-1.0～1.5,且初始生长期波动呈上升趋势;SAPEI空间变化总体特征表现为初始生长期和快速发育期玉米生长气候湿润化趋势表现明显,生育中期和成熟期东部及南部气象站点表现为变旱趋势;玉米生育期内多年平均旱积指数Q_dl总体呈东南高西北低的格局分布,即西北部大于东南部;多年平均渍积指数Q_wl在21.07～37.85内变化,年均旱积与渍积指数的分布格局与河北省降水分布格局相呼应。研究结果可为河北省农业气象灾害风险评估和防灾减灾管理决策提供理论依据。     

近55年以来漳卫河流域干旱演变特征分析

以漳卫河流域11个气象基准站1957-2011年降水日值资料为基础,基于标准化降水指数选取干旱发生频次、干旱影响范围、干旱强度与历时、干旱重心等指标,分析了流域降水突变前后气象干旱演变特征。结果表明：流域降水在1976年发生突变,降水突变前后,年尺度干旱发生频次和影响范围显著增加,分别由20%、23.2%增加到40%、34.1%;在季尺度上,春旱发生频次和影响范围均有较大程度减少,夏旱和秋旱的发生频次和影响范围有所增大,冬旱的发生频次和影响范围分别有小幅度的增大和减少;年尺度和季尺度干旱的平均干旱历时和强度增加显著,而月尺度干旱的干旱历时和强度略有下降;流域干旱重心在降水突变前后未发生明显的变化。     

基于干旱区的大豆高效节水灌溉制度制定

大豆属于需水较多的旱作物,对土壤水分的要求比较严格,土壤水分充足与否,对大豆各生育阶段的发育及产量形成,都有较大的影响。文章对大豆不同生育期的土壤水分,制定出干旱区大豆的节水灌溉制度。     

作物生长与土壤水氮运移联合模拟的研究Ⅱ——模型验证与应用

在华北平原中国农业大学东北旺实验田开展了水肥耦合灌溉实验,设置了传统和优化水肥4个组合处理,同时应用作者提出的联合模拟模型SPWS对2000年夏玉米生育期内的土壤水分、氮素转化运移以及水氮限制条件下夏玉米的叶面积指数、干物重、吸氮量及籽粒产量进行了模拟,模拟结果与实测数据均吻合良好。水氮平衡分析结果表明,优化灌溉和优化施肥管理措施均能明显减小水分渗漏、硝酸盐淋失和氮素的气体损失,且均有不同程度的增产作用,其中优化水肥处理下水氮利用率分别为1.33kg/m3和31.6kg/kgN,为4个组合处理中最高。