区域农业灌溉用水量长期预报模型研究

农业灌溉用水是一动态、非平衡随机过程,其水量预报中存在灰色不确定信息。如何通过大面积农业灌溉用水量的长期预报,指导灌区用水实时管理,则是水利工程规划管理和农业高效用水中待研究的重要问题。本文基于时间序列分析方法,建立了区域农业灌溉用水量长期预报分解模型,给出了灰色ＧＭ（１,１）趋势预测、方差周期分析以及ＡＲＭＡ（２ｎ,２ｎ－１）随机分析相结合的模型求解方法,并编制了相应模型软件支持系统。该系统具有     

灰色预测模型在广西达开水库灌区农业灌溉用水管理中的应用

在分析现有灌溉用水量预测方法的基础上,运用灰色系统理论,以达开水库灌区1967-2011年农业灌溉用水量为样本,建立了GM(1,1)预测模型,对该灌区未来5年农业用水量进行外推预测。根据预测结果,提出了优化达开水库灌区灌溉用水管理的措施,促进了灌区的管理。     

基于灰色GM(1,1)模型的库尔勒市农业用水量预测

介绍灰色理论建模原理和模型参数辩识方法,并以实例(库尔勒市2000-2006年灌溉用水资料)建立灰色GM(1,1)预测模型,运用残差检验、后验差检验以及关联度检验3种方法对模型进行精度检验,其模型拟合精度达96.9%.用所建立的模型对库尔勒市2007-2011年农业用水量进行外推预测.结果表明,该灰色模型用于农业用水量预测,符合其灰色特性,通用性好,并且所需数据少,计算量适中,预测结果与当地实际情况比较吻合.     

改进灰色预测模型在灌溉用水量建模中的应用

灌溉用水量系统受诸多不确定性因素的影响,采用灰色预测方法对甘肃省灌溉用水量进行建模分析.通过对灰色GM(1,1)模型的预测精度的分析表明,GM(1,1)预测公式系数的选取存在缺陷.因此基于残差和为零准则,就预测公式系数C的选取问题提出新的计算方法,并对系数修正前后的模型分别建模.结果表明;改进灰色模型预测灌溉用水量与实际用水量更接近、精度更高.     

灰色预测在作物需水量推算中的应用

该文运用灰色预测方法进行作物需水量预报。除以１９８０－１９９１年实测数据序列进行整体建模外，还以降雨频率为基础分为正常年及灾年（丰，枯）年型的子序列建立全生育期Ｇ（１，１）模型。同时按水稻不同生育期需水量本身及同相应的积温建立Ｇ（１，１）与Ｇ（１，２）预测模型。经水稻需水量观测数据建模预测，其结果效果好，精度高，得于在灌溉水量预报，制定用水计划，水源调度中广泛应用。     

等维灰数递补动态模型在城市生活用水量预测中的应用

运用灰色系统理论中“等维灰数递补动态模型”对城市生活用水量进行了分析与预测。一是对用水人口进行预测,并运用回归理论对城市生活用水量与用水人口的关系建立模型,对城市生活用水量进行了预测;二是运用等维灰数递补动态模型直接对生活用水量进行预测。     

两种新的灌溉用水管理仪器

美国农业部农业研究机构及水与动力资源局研制了两种新的灌溉用水管理仪器: 一、自动预报计算灌溉日期和灌水量仪这种仪器是将气象数据及土壤水分.作物生态等资料输入电子计算机,可计算不同作物用水量。预报各地块和各种作物下一次灌溉日期和灌水总     

基于DTW-ILC算法的农业灌溉用水量调控方法

为了有效提高农业灌溉用水的利用率,根据农业灌溉的用水量,采用2级灌溉,先蓄水再灌溉的策略。在每次灌溉前,根据动态时间弯曲-迭代学习控制（DTW-ILC）方法的思想,先计算出灌溉用水,将其存放在蓄水池中,再根据实际农业灌溉用水量进行灌溉,反复用计算出来的蓄水池储水量逼近实际用水量,达到修正系统参考模型的作用,同时将下次灌溉的用水存储在蓄水池中,可以很好地预防干旱带来的无水灌溉的问题。仿真结果表明经过几次蓄水灌溉的过程可以很好地跟踪农业灌溉的实际用水量,提前作好蓄水池的蓄水工作,需要灌溉时有适当的灌溉用水,减少浪费,最终达到节水目的。     

灌溉管理应用软件的研究现状及前景

灌溉用水管理是整个灌区的工作重点。决策支持系统等人工智能应用于灌溉管理,辅助管理人员及高层领导正确决策,解决知识处理中的半结构、非结构化问题,缩短预报周期,提高调度的实时性和可靠性,是二十一世纪灌溉系统管理的发展方向。最后介绍了霍泉灌区灌溉用水管理决策支持系统（简记：ＨＱＩＷＡＤＳＳ）的程序结构和主要功能     

加权马尔科夫链模型在农业灌溉用水预测中的应用研究

应用加权马尔科夫链数学模型对农业灌溉用水进行年和月尺度预测,并对比分析未加权马尔科夫链的预测精度,研究结果表明:相比于传统未加权马尔科夫链,加权马尔科夫链的农业灌溉用水预测精度明显有所改善,其与调查的农业灌溉用水的年和月尺度相关系数分别达到0.712 1和0.866 6,高于未加权的马尔科夫链的预测精度;对于不同时间尺度而言,加权马尔科夫链模型预测的灌溉用水和调查灌溉用水量虽在月尺度相关系数大于年尺度相关系数,但年尺度预测相对误差明显小于月尺度预测相对误差。     

平原井灌区地下水多年调节配水模型及其应用

华北平原纯井灌区水资源严重不足。限水灌溉是保持地下水平衡、农业可持续发展的必要条件,通过对作物耗水规律及地下水动态规律的分析,在保持地下水多年平衡的前提下,不追求个别年份高产,以多年粮食总产量最高为目标,提出了地下水均衡开采的调节配水模型,并采用非线性规划理论对该模型进行了论证。应用该模型可计算出不同水文年地下水开采量及各作物灌溉定额,进而计算灌溉制度,可广泛应用于纯井灌区的井灌工程的规划设计。     

Sustainability of conjunctive water use for salinity control in irrigation areas: theory and application to the Shepparton region,Australia

The long term sustainability of conjunctive water use for controlling irrigation salinity is affected by increase in groundwater salinity over time. This paper uses mass conservation of salt and water to assess groundwater degradation over long time scales. Management options which affect this rate of degradation are also examined. The groundwater model developed is illustrated using data from the Shepparton Irrigation Region in the Murray Basin, Australia. The model predicts rapid groundwater deterioration when conjunctive use is conducted over only a fraction of the area of influence of a groundwater pump. Where the pumped aquifer is underlain by deeper groundwaters, the rate of groundwater degradation is also affected by leakage into or out of the conjunctive use system. Surface redistribution of groundwater from pumps installed in zones of regional groundwater discharge to areas recharging the regional groundwaters, reduces excessive degradation in the zones of discharge. With optimal surface distribution of groundwater, the rate of degradation is low. The rate of groundwater degradation also depends on salt inputs from irrigation water and rainfall, and the average depth from the soil surface to the base of the aquifer. The rate of degradation resulting from applied salts in surface water and rainfall is typically about 0.01 dSm^-1 per year for shallow aquifers in the Shepparton region, but the rate is lower where deeper aquifers are pumped. Partial irrigation also reduces the rate of degradation because of the reduced rate of salt inputs. Where poorer quality groundwater lies within the area of influence of the groundwater pump, a greater rate of deterioration in the quality of pumped groundwater can be expected from groundwater mixing. In some irrigation regions limited export of groundwater through surface water conveyance structures to a river is possible, so that a regional surface salt balance could be maintained. However, salt exports made equal to the rate of surface imports into the irrigated area will only significantly impact groundwater salinity in the very long term, or where only shallow aquifers can be pumped. In addition, this export can be costly for downstream water users, or if construction of additional conveyance infrastructure is extensive; export can have a detrimental impact on riverine ecosystems. Other management options such as the depth of pump installation and the spatial distribution of irrigation water and pumped groundwater, which affect the redistribution of salts within the groundwater system, have the potential to have a much greater impact on local groundwater salinity.     

Long-term solute dynamics and hydrology in irrigated slowly permeable soils

Summary A simple model is given, based on mass conservation of a non-transformed non-absorbed solute or ion (such as the chloride ion), which allows long term trends in the concentration of this solute to be predicted. The method involves solution of an implicit equation for the long term through-drainage flux below the maximum depth of sampling. A knowledge of the initial chloride ion concentration in the soil depth of interest, and its value after a known application via irrigation water provides sufficient information for the model to be applied. The model is applied to data from an irrigated slowly permeable swelling clay soil. A drainage flux of 8 cm yr^–1 beneath paddy rice was inferred, and some twenty-five years after commencement of irrigation an equilibrium soil salinity of 22 meq/l at saturation was predicted.     

作物节水灌溉需水规律研究

基于节水灌溉条件下作物需水量试验资料,分析了控制灌溉和覆膜旱作节水灌溉的水稻需水规律以及节水高效灌溉模式下冬小麦、夏玉米和棉花作物的需水规律。结果表明,节水灌溉模式通过对水稻、冬小麦、夏玉米和棉花等作物产生的生长调控作用与补偿生长效应,使植株蒸腾量和棵间蒸发量较大幅度减少,各阶段需水量、需水强度和需水模系数均发生显著变化,形成了节水灌溉模式的主要农作物新的需水规律。可为节水灌溉制度的制定、节水型灌区动态配水及灌溉预报等提供科学依据。     

节水灌溉的作物需水量试验研究

对节水灌溉条件下的冬小麦、夏玉米、棉花和水稻需水量进行试验研究 ,结果表明 ,节水灌溉模式对作物需水量变化产生较大影响。与浅水灌溉模式相比 ,控制灌溉模式的水稻需水量减少 3 4.6% ,覆膜旱作节水模式的水稻需水量减少 3 9.94%。采用节水灌溉模式后 ,冬小麦需水量减少 1 0 %左右 ,夏玉米需水量减少1 3 % ,棉花需水量减少 3 0 %。因此 ,对大田农作物进行高效节水灌溉 ,能在获得高产 (增产 )的前提下 ,较大幅度地减少作物的蒸发蒸腾量 ,其中无效蒸腾量的减少成为主要因素之一     

灌区节水潜力估算的方法及应用

从作物需水量出发 ,考虑有效降水、地下水、输水损失、田间损失、无效蒸腾等因素后 ,构造了一个理论节水潜力的计算公式 ,继而利用一个调节因子 ,求得实际节水潜力     

Agricultural water management in a humid region: sensitivity to climate,soil and crop parameters

A sensitivity analysis of irrigation water requirements at the regional scale was conducted for the humid southeastern United States. The GIS-based water resources and agricultural permitting and planning system (GWRAPPS), a regional scale, GIS-based, crop water requirement model, was used to simulate the effect of climate, soil, and crop parameters on crop irrigation requirements. The effects of reference evapotranspiration (ET_o) methods, available soil water holding capacities (ASWHC), crop coefficients (K_c), and crop root zone depths (z) were quantified for 203 ferneries and 152 potato farms. The irrigation demand exhibited a positive relationship with K_c and z, a negative relationship with ASWHC, and seasonal variations depending on the choice of ET_o methods. The average irrigation demand was most sensitive to the choice of K_c with a 10% shift in K_c values resulting in approximately 15% change in irrigation requirements. Most ET_o methods performed reasonably well in estimating annual irrigation requirements as compared to the FAO-56 PM method. However, large differences in monthly irrigation estimates were observed due to the effect of the seasonal variability exhibited by the methods. Our results suggested that the selection of ET_o method is more critical when modeling irrigation requirements at a shorter temporal scale (daily or monthly) as necessary for many applications, such as daily irrigation scheduling, than at a longer temporal scale (seasonal or annual). The irrigation requirements were more sensitive to z when the resultant timing of irrigation coincided with rainfall events. When compared with the overall average of the irrigation requirements differences, the site-to-site variability was low for K_c values and high for the other variables. In particular, soil properties had considerable average regional differences and variability among sites. Thus, the extrapolation of site-specific sensitivity studies may not be appropriate for the determination of regional responses crop water demand.     

基于CROPWAT的泾惠渠灌区玉米和棉花灌溉需水量时空分布研究

基于泾惠渠灌区30a的气象资料,采用CROPWAT模型分析了泾惠渠灌区作物蒸发蒸腾量及灌溉需水量的变化,并运用SPSS软件,计算了灌区作物需水量与气象因子的相关系数。分析表明:玉米蒸发蒸腾量平均值为524.33mm,蒸发蒸腾量高峰期出现在7月中旬到8月下旬;棉花蒸发蒸腾量平均值为869.13mm,峰值出现时间与玉米一致;灌区玉米在抽雄-开花期灌溉需水量为130.12mm,籽粒形成-乳熟期灌溉需水量为359.32mm,9月下旬以后,灌溉需水量下降;棉花生育期需水量空间分布比较均匀,平均值为869 mm,整个灌区灌溉需水量平均值为453.6mm,棉花苗床期灌溉需水量开始增加,花铃期达到最大值,吐絮期灌溉需水量减小;灌区作物需水量与气温呈正相关,与降水呈负相关,与风速和相对湿度相关性较小,与日照时数相关性较大。     

A field test of a conceptual computer simulation model for predicting water and salt distribution

Summary The unsaturated flow and unsaturated chemistry submodels of a conceptual computer simulation model, developed at the United States Bureau of Reclamation to predict water and salt behaviour in soils, were tested under field conditions. The comparison of results was done with data obtained from an irrigation trial with alfalfa over a period of four years. The model simulated the actual physical and chemical processes taking place in the soil to a fair degree of accuracy. The predicted moisture contents compared reasonably well with ob served data, especially in the soil layers between 480 and 1200 mm (Figs. 1 and 2, Tables 3 and 4). The simulation of moisture distribution was more accurate for plots receiving a high irrigation frequency than for plots given a low irrigation frequency. On a depth-weighted-mean scale, the predicted salt concentration of the soil layers shallower than 1200 mm was within 11% of the observed data. However when the salt content of the soil layers between 1200 and 1920 mm was taken into account, the percentage error increased to about 40% (Table 6). The results indicate that this simulation model can be extremely useful in predicting the long and short term effect of irrigation water on the root zone of a soil. Field data are however at all times needed to calibrate the unsaturated flow model for specific soil types.     

A statistical approach for estimating irrigation water usage in western Saudi Arabia

This paper presents a statistical practical approach to the estimation of irrigation water requirement in the western region of Saudi Arabia. The approach describes the variation in water requirements as a function of regional climatic parameters, types of crop grown and irrigation techniques used. Irrigation water requirements are also calculated, for comparison purposes, by Modified Penman and Blaney-Criddle methods, taking leaching requirements and losses into consideration. It is found that irrigation water requirements for vegetables and perennial crops are close to the values estimated by Blaney-Criddle method, while for fodder and cereal they are close to the values estimated by Modified Penman Method.