Irrigation Zone Research Articles

Predictive ability of machine learning methods for massive crop yield prediction

An important issue for agricultural planning purposes is the accurate yield estimation for the numerous crops involved in the planning. Machine learning (ML) is an essential approach for achieving practical and effective solutions for this problem. Many comparisons of ML methods for yield prediction have been made, seeking for the most accurate technique. Generally, the number of evaluated crops and techniques is too low and does not provide enough information for agricultural planning purposes. This paper compares the predictive accuracy of ML and linear regression techniques for crop yield prediction in ten crop datasets. Multiple linear regression, M5-Prime regression trees, perceptron multilayer neural networks, support vector regression and k-nearest neighbor methods were ranked. Four accuracy metrics were used to validate the models: the root mean square error (RMS), root relative square error (RRSE), normalized mean absolute error (MAE), and correlation factor (R). Real data of an irrigation zone of Mexico were used for building the models. Models were tested with samples of two consecutive years. The results show that M5-Prime and k-nearest neighbor techniques obtain the lowest average RMSE errors (5.14 and 4.91), the lowest RRSE errors (79.46% and 79.78%), the lowest average MAE errors (18.12% and 19.42%), and the highest average correlation factors (0.41 and 0.42). Since M5-Prime achieves the largest number of crop yield models with the lowest errors, it is a very suitable tool for massive crop yield prediction in agricultural planning.

Effect of Irrigation Pattern and Timing on Root Density of Young Citrus Trees Infected with Huanglongbing Disease

Citrus (Citrus sp.) root length density (RLD) can help in understanding and predicting nutrient and water uptake dynamics. A study was conducted at two sites in Florida to investigate root and water distribution patterns among different irrigation and fertigation systems. The results over the 2 years showed that RLD was highest in the 0- to 15-cm soil depth and decreased with depth for all treatments at both sites. About 64% to 82% of the fibrous roots (<1 mm diameter) were concentrated in the irrigated zones of drip- and microsprinkler-irrigated trees and 18% to 36% were found in the nonirrigated zones at the Spodosol site (SS). At the Entisol site (ES), the RLD (<0.5 mm diameter) in the 0- to 15-cm depth soil for intensive microsprinkler or drip irrigation was 3- to 4-fold (nonirrigated zone) and 4- to 7-fold (irrigated zone) greater at the 0- to 15-cm soil depth than that for conventional irrigation system. The trees at SS were symptomatic for Huanglongbing (HLB; Candidatus Liberibacter asiaticus) in the second year, while those at ES were asymptomatic throughout the study. This might have limited the density and extent of root distribution at SS. The water contents remained either close to or slightly above the field capacity. The results showed higher RLD for intensive irrigation and fertigation practices in irrigated zones compared with conventional grower applications suggesting greater water and nutrient uptake potential for the former.

Ammonium and Nitrate Distribution in Soil Using Drip and Microsprinkler Irrigation for Citrus Production

Good management of N is critical for improved citrus production and environmental sustainability on Florida sandy soils. Thus, understanding N movement in the root zone is important to devise appropriate nutrient management strategies. Field experiments were conducted on citrus at two sites in Florida to: (i) determine the soil moisture distribution in the irrigated and unirrigated zones as a function of time and depth; (ii) determine NH4+–N and NO3−–N distribution patterns in the irrigated and unirrigated zones as a function of depth, lateral distance, and fertilizer application method; and (iii) determine NH4+ sorption in a fertilizer mixture due to cation exchange. The treatments were (i) a simulated conventional grower practice, irrigated periodically with a large-pattern microsprinkler; (ii) a simulated open hydroponic system, drip irrigated and fertigated daily in small pulses; and (iii) a simulated open hydroponic system irrigated using a small-pattern microsprinkler. The experiment was arranged in a randomized complete block design with four replicates. Soil moisture contents varied between 5 and 15%, remaining close to field capacity. Approximately 16 to 100% greater NH4+–N and NO3−–N concentrations were observed in the irrigated zones of the intensively managed drip or restricted microsprinkler irrigation than conventional practice. Ammonium adsorption followed a linear isotherm, with sorption coefficients varying between 1 and 2.2 L kg−1. The results suggest the possibility of promoting nutrient retention and availability with intensive fertigation, thereby decreasing the potential for N leaching beyond the root zone.

Phosphorus and Potassium Distribution and Adsorption on Two Florida Sandy Soils

Phosphorus and K are critical nutrients in citrus production whose deficiency or excess can affect yield, fruit quality, and water quality. However, no study has been conducted to understand the nutrient distribution in the root zone using intensive fertigation practices in Florida’s sandy soils. Thus, experiments were conducted to: (i) compare the performance of intensively managed drip and microsprinkler fertigation systems with conventional grower practices; and (ii) determine P and K adsorption based on recommended fertilizer application rates on Candler (hyperthermic, uncoated Lamellic Quartzipsamments) and Immokalee (sandy, siliceous, hyperthermic Arenic Alaquods) fine sands. Phosphorus and K were applied and tracked with time and distance from point of application. Soil P on Immokalee soil was 27 to 163% higher in the irrigated zone for drip and restricted microsprinkler fertigation than the unirrigated zone and up to 70% greater in the 0- to 15-cm depth of the irrigated zone than conventional microsprinkler practices. Soil K was 5 to 61% greater in the upper 0- to 15-cm of the irrigated zone with drip and microsprinkler fertigation than conventional microsprinkler practices on Immokalee fine sand. Soil P and K on Candler also differed by fertilization method, depth, and between irrigated and unirrigated zones. The linearized P sorption coefficients for Candler were three- to fourfold greater than the corresponding depths for Immokalee, while sorption coefficients for K were similar for the two soils. It is unlikely that P or K would present a water quality concern as strictly related to irrigation practice. The P application rate for Candler should be lowered for young trees (<3 yr old).

Partial root zone drying exerts different physiological responses on field-grown grapevine (Vitis vinifera cv. Monastrell) in comparison to regulated deficit irrigation.

Regulated deficit irrigation (RDI) and partial root zone irrigation (PRI) were compared for 4 years at two irrigation volumes (110mm year-1 (1) and 78mm year-1 (2)) in field-grown grafted Monastrell grapevines (Vitis vitifera L.) to distinguish the effects of deficit irrigation from specific PRI effects. PRI-1 and RDI-1 vines received ~30% of the crop evapotranspiration (ETc) from budburst to fruit set, 13-15% from fruit set to veraison and 20% from veraison to harvest. RDI-2 and PRI-2 vines received around 20% of ETc from budburst to fruit set, no irrigation from fruit set to veraison, and recovery (21-24% ETc) thereafter. Compared with RDI-1, PRI-1 increased irrigation depth and total soil water (θv) availability in the root zone, and stimulated greater fine root growth and water uptake. Increased soil volume exploration supported greater canopy water use, vegetative development, biomass accumulation and internal water storage capacity. PRI-1 vines had higher stomatal conductance, lower leaf-level water use efficiency and increased leaf xylem sap concentration ([X-ABA]leaf) following reirrigation. Compared with RDI-2, PRI-2 decreased total θv availability, fine root growth and water uptake, gas exchange, leaf water status, [X-ABA]leaf, biomass accumulation and storage capacity. Xylem ABA decreased with total θv availability in PRI-2, probably from limited sap flow when θv in drying soil was low (≈20%). For this rootstock-scion combination, high irrigation volumes applied to the wet part of the roots (θv>30%) are critical for increasing root-to-shoot ABA signalling and growth, and improving performance under semiarid conditions.

区域性水土空间变异的人工神经指示克立格技术研究

本文基于非参数地质统计学的指示Kriging法思想，借助人工神经网络高度非线性逼近的技术优点，以河套灌区内一典型实验区的土壤水盐空间变异性为案例，进行了非参数统计与人工智能技术的创新性融合研究。经与普通克立格、BP神经网络、指示克立格与析取克立格估计值对比分析发现：人工神经指示克立格法具有指示克立格的优点，即对数据无统计假定，不涉及特异值识别与处理，又可以高度逼近线性与非线性函数，很好地解决非线性估值问题，可用于土壤水盐监测及相关工作中。 Based on the spatial variation of soil water-salt at one representative experimental section in Hetao irrigation zone, directed by Indicator Kriging of non-parameter Geostatistic theory, using the high non-linear approximating ability of ANN, this paper innovated fusion of the non-parameter statistic and artificial intelligence technologies. Compared with the Ordinary Kriging, BP, Indicator Kriging, and Distinctive Kriging estimating values, it is founded that Artificial Neural Indicator Kriging has the characteristics of indicator kriging: 1) no need to make statistical assumptions for raw data; 2) not involving identification and specificity values treatment; 3) a high degree of approximation of linear and nonlinear functions; which can solve nonlinear problems effectively, so it can be used to monitor soil water and salt and the related work.

引黄灌区土壤有机碳密度剖面特征及固碳速率研究

PDF HTML阅读 XML下载 导出引用 引用提醒 引黄灌区土壤有机碳密度剖面特征及固碳速率 DOI: 10.5846/stxb201211051537 作者: 作者单位: 南京师范大学地理科学学院,南京师范大学地理科学学院,南京师范大学地理科学学院,中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划“973”资助项目（2010CB950702）；中国科学院战略性先导科技专项资助项目（XDA05050507）；博士后基金资助项目（1202051C） Profile distribution patterns of soil organic carbon and the rate of carbon sequestration in Ningxia Irrigation Zone Author: Affiliation: College of Geographical Science,Nanjing Normal University,College of Geographical Science,Nanjing Normal University,College of Geographical Science,Nanjing Normal University,State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为揭示灌溉耕作对土壤有机碳密度剖面（0-100 cm）分布产生的影响，通过在宁夏引黄灌区进行实地调查与采样，以无灌溉耕作的自然土壤作为对照，研究不同灌溉耕作时间序列下灌区土壤有机碳密度的剖面分布特征，并估算其平均固碳速率。结果表明：灌区土壤有机碳含量具有随土层深度增加而下降的剖面分布特征，灌溉耕作对增加表层土壤有机碳含量作用最明显；灌区土壤剖面碳密度与灌溉耕作时间和土壤类型均显著相关（P < 0.01），相关系数分别为0.63和 0.74，且因灌溉耕作时间和土壤类型的不同，土壤有机碳密度差异性显著（P < 0.05）；灌溉耕作影响的土层深度及剖面土壤有机碳密度的增加量因灌溉耕作时间长短的不同而异；引黄灌区5类土壤的平均固碳速率为0.53 MgC · hm-2 · a-1。引黄灌溉耕作在增加农田土壤固碳中发挥着重要作用。 Abstract:To reveal the effect of irrigation with sediment laden water from the Yellow River on soil organic carbon (SOC) distribution in profile (0-100 cm), Ningxia Irrigation Zone was selected as the study area to carry out the research. Totally, 40 soil profiles of five soil types (Irrigation-silted soils, Fluvo-aquic soils, Sierozem soil, Aeolian sandy soil and Alluvial soils) were collected, including 34 cropland profiles with the irrigated durations ranged from 10 to 2200 years and 6 natural soil profiles never irrigated and cultivated, to analyze profile distribution patterns of SOC content and density under different durations of irrigation and cultivation. The natural soil profiles were used as control profiles and their irrigation duration were set to zero. Pearson correlation coefficients were calculated to determine relationships between SOC density and irrigation durations and soil types. SOC content and density were subjected to analysis of variance (ANOVA) to test difference of irrigation effects from irrigation years and soil types at 5% probability level, respectively. SOC sequestration rate was also estimated by comparing irrigated soils with control ones.Results indicated that SOC content of irrigated cropland showed a decreasing trend with the deepening of soil layers in profile. SOC content of surface layer (0-20 cm) affected mainly by irrigation and cultivation increased more rapidly than those of deeper layers affected mainly by soil parent material. When the irrigated duration was about 50 years, the SOC content showed the most significant difference among the five soil types. The irrigation-silted soil layer formed by irrigation and cultivation activities, usually thicker than 50 cm, were found in those areas with such activities of 50 years over. The depth influenced by irrigation and the increment of SOC density both are different due to the difference of irrigation durations. SOC density was significantly related with irrigation durations and soil types, the correlation coefficients were 0.63 (P < 0.01) and 0.74 (P < 0.01), respectively. SOC density in the profile depth were significant different (P < 0.05) among varied irrigation durations and soil types. SOC density increment was significantly and positively correlated with irrigation durations shorter than 50 years. On average, the SOC density increment of the cropland soils in depth of 0-20, 20-30, 30-60 and 60-100 cm were 14.69, 4.52, 9.84 and 9.52 Mg/hm2 more than the corresponding soil layers of their control profiles. SOC density increment of irrigation-silted soils formed under the long-term alternate activities of irrigation, manure addition, silting and cultivation, was more than other four soil types in Ningxia Irrigation Zone. The linear relationships between SOC density increments and irrigation durations inferred that average SOC sequestration rate reached 0.53 MgC · hm-2 · a-1 from the five soil types in Ningxia Irrigation Zone. The SOC sequestration rate varied among soil types.Results discussion indicated, by stimulating plant and root growth as well as soil biotic activity,irrigation could potentially enhance SOC sequestration of cultivated land in the arid and semi-arid area. In addition, irrigation with sediment laden Yellow River water via sediment with organic matter silting, make the irrigation-silted soil layer thicker at the top of profile, and SOC increased accordingly. Overall, irrigation by the Yellow River water plays an important role in increasing SOC density. 参考文献 相似文献 引证文献

Experimental hut and bioassay evaluation of the residual activity of a polymer-enhanced suspension concentrate (SC-PE) formulation of deltamethrin for IRS use in the control of Anopheles arabiensis

BackgroundThe Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004; the use of DDT for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for indoor residual spraying (IRS) have a relatively short residual duration of action (2-6 months according to WHO). In areas of year-round transmission multiple spray cycles are required, resulting in significantly higher costs for malaria control programs and user fatigue. This study evaluated performance of a new formulation of deltamethrin (pyrethroid) with polymer (SC-PE) to prolong the effective residual action to >6 months.MethodsDeltamethrin SC-PE was evaluated alongside an existing water dispersible granule (WG) formulation and DDT water dispersible powder (WP) in laboratory and hut bioassays on mud, concrete, palm thatch and plywood substrates. An experimental hut trial was conducted in Lower Moshi Rice Irrigation Zone, Tanzania from 2008-2009 against wild, free-flying, pyrethroid susceptible An. arabiensis. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Bioassays were carried out monthly on sprayed substrates to assess residual activity.ResultsBioassays in simple huts (designed for bioassay testing only) and experimental huts (designed for testing free flying mosquitoes) showed evidence that SC-PE improved longevity on mud and concrete over the WG formulation. Both deltamethrin SC-PE and WG outperformed DDT in bioassays on all substrates tested in the laboratory and simple huts. In experimental hut trials SC-PE, WG and DDT produced high levels of An. arabiensis mortality and the treatments were equivalent over nine months’ duration. Marked seasonal changes in mortality were recorded for DDT and deltamethrin treatments, and may have been partly influenced by outdoor temperature affecting indoor resting duration of mosquitoes on sprayed surfaces, although no clear correlation was demonstrated.ConclusionsThere is a limited range of alternative insecticides for IRS, and deltamethrin SC-PE is likely to have an important role as part of a rotation strategy with one or more different insecticide classes rotated annually, particularly in areas that currently have low levels of pyrethroid resistance or low LLIN coverage and year-round malaria transmission.

根域に対する灌水域の割合がカンキツ樹の乾燥ストレスに及ぼす影響

根域に対する灌水域の割合がカンキツ樹の乾燥ストレスに及ぼす影響

不同水氮条件下灌溉方式对玉米干物质量和氮钾利用的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 不同水氮条件下灌溉方式对玉米干物质量和氮钾利用的影响 DOI: 10.5846/stxb201405090921 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重点项目（U1033004）；国家863计划（2011AA100504） Effect of irrigation method on dry mass and nitrogen and potassium utilization of maize under different water and nitrogen conditions Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:由于作物需水随生育期的变化，分根区交替灌溉（AI）的节水效果也会随生育期而发生变化，探明不同生育期分根区交替灌溉对玉米生长和水分养分利用的影响，以期为分根区交替灌溉的实施和充分发挥其节水节肥效果奠定理论基础。通过盆栽试验，在2种灌水水平（正常灌水和轻度缺水）和2种有机无机氮比例（100%无机氮和70%无机氮+30%有机氮）下，以常规灌溉（CI）为对照，分别研究苗期-灌浆初期、苗期-拔节期以及拔节期-抽雄期进行AI对玉米干物质量、氮钾含量和吸收量以及土壤碱解氮和速效钾含量的影响。结果表明，在轻度缺水和有机无机氮肥配施下，与CI相比，拔节期-抽雄期分根区交替灌溉玉米地上部和总干物质量分别增加29.6%和27.4%，地上部和总N吸收量增加50.7%和50.4%。与单施无机氮肥相比，有机无机氮肥配施会在不同程度上增加地上部和总N吸收量，但是一般降低土壤碱解氮和速效钾含量，这说明在轻度缺水和有机无机N肥配施下，拔节期-抽雄期进行分根区交替灌溉提高玉米总干物质量和N吸收量。 Abstract:Crop water requirement varies with the growth stage, so water-saving effect of alternate partial root zone irrigation (AI) also varies with the growth stage. Understanding the effect of alternate partial root-zone irrigation at different growth stages on maize growth and water and nutrient utilization can provide the theoretical foundation for the implement of alternate partial root zone irrigation and fully exerting its effect of saving water and fertilizer. Taking conventional irrigation (CI) as the control, this study has investigated the effects of AI respectively at seedling- early grain filling, seedling-jointing and jointing-tasselling stages on dry mass, nitrogen and potassium contents and uptakes of maize and available N and K contents in soil using a pot experiment under two irrigation levels (normal irrigation and mild water deficit) and two ratios of inorganic to organic N (100% inorganic N and 70% inorganic N + 30% organic N). Results indicate that under mild water deficit and combined application of organic and inorganic N fertilizer condition, AI at the jointing-tasselling stage increased shoot and total dry masses by 29.6% and 27.4%, and shoot and total N uptakes by 50.7% and 50.4%, respectively, if compared to CI. Combined application of organic and inorganic N increased shoot and total N uptakes to some extent, but generally reduced soil available N and K contents when compared to only inorganic N. Thus alternate partial root-zone irrigation at the jointing-tasselling stage could increase total dry mass and N uptakes under mild water deficit and combined application of organic and inorganic N fertilizer. 参考文献 相似文献 引证文献

Effects of Partial Root Zone Irrigation on Leaf Photosynthetic Curves and Chlorophyll Fluorescence Parameters in Naked Oat

The objective of this study was to provide experimental evidence for photosynthetic mechanism under drought stress and practical technique of water-saving irrigation in naked oat(Avena nuda L.).In a pot experiment with instrument to control root zone irrigation and water amount,the effects on relative chlorophyll content(SPAD),photosynthetic curves,and chlorophyll fluorescence parameters were compared among irrigation models of alternative partial root zone irrigation(APRI),fixed partial root zone irrigation(FPRI),and conventional total root zone irrigation(CTRI).Compared to CTRI,partial root zone irrigation,including APRI and FPRI treatments,decreased leaf SPAD,net photosynthetic rate(Pn),and carboxylation efficiency(CE);however,APRI had no obvious effects on reducing initial quantum efficiency(α),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency of PSII(ФPSII),apparent electron transport rate(ETR),and photochemical quenching coefficient(qP).The leaf SPAD of APRI was significantly enhanced compared to that of FPRI(P0.05),and the maximum net photosynthetic rate(Pmax),α,light saturation point(LSP),light use efficiency(LUE),Ci/Ca,CE,CO2 saturation point(Ci,sat),Fo,Fm,ФPSII,ETR,qP,and NPQ were all higher in APRI than in FPRI.The reduction of Pn in partial root zone irrigation treatments resulted from stomatal factors,and structural damage of photosynthetic system II(PSII) was found in FPRI treatment.Clearly,partial root zone irrigation can improve the tolerance ability of naked oat against drought stress;particularly,APRI has the effect to maintain higher Pn than FPRI.

Assessing Application Uniformity of a Variable Rate Irrigation System in a Windy Location

<abstract><title><italic>Abstract. </italic></title> Variable rate irrigation (VRI) systems are commercially available and can easily be retrofitted onto moving sprinkler systems. However, there are few reports on the application performance of such equipment. In this study, application uniformity of two center pivots equipped with a commercial VRI system were tested using fixed-plate sprinklers and a range of irrigation rates (100%, 80%, 70%, 50%, and 30%). Catch cans were arranged in transect, arc-wise, and grid patterns to test the accuracy of application depth, and the uniformity of application in the direction of pivot travel and to investigate changes in uniformity along the pivot lateral between irrigation zones. The mean Heermann and Hein coefficient of uniformity (CU_HH) and the mean lower-quarter distribution uniformity (DU_lq) in the direction of pivot travel and along the pivot lateral were approximately 88% and 80%, respectively. Application uniformity was impacted at the border of adjacent irrigation zones along the pivot lateral when zones were applying different irrigation depths. While wind speed and direction did not appreciably decrease uniformity of application, it did impact absolute catch measurements. The mean evaporation and drift loss for all trials was 9.3%, and ranged from 1% to 19%. Applying variable rate irrigation significantly impacted uniformity of application for a distance 3 m wide between irrigation zones of different irrigation depths in spans 1-3 of the three-span, and a distance 6 to 9 m wide between irrigation zones in spans 5 and 6 of the six-span center pivot. Overall, the uniformity of application in the direction of pivot travel and within each irrigation zone was similar to values reported for other VRI sprinkler systems. The root mean square error between the prescribed and actual applied depth was <3.0 mm for catch collected in all spans along the pivot lateral and in the direction of pivot travel. This indicates that this commercial VRI is well suited for site-specific irrigation management. However, uniformity of application could be affected by the width of the irrigation management zones as well as sprinkler design and environmental factors.

Development of genus‐specific primers for better understanding the diversity and population structure of Sphingomonas in soils

Genus Sphingomonas has received increasing attentions due to its somewhat unique metabolic versatilities in the contaminated environment. However, due to the lack of genus-specific primers, the ecological significance of Sphingomonas in polluted soils has been rarely documented by 16S rDNA finger-printing methods. In this study, three genus-specific primer sets targeted at the 16S rRNA gene of Sphingomonas were developed and their specificities were tested with four contaminated soils from Shenfu petroleum-wastewater irrigation zone by constructing clone libraries, amplified ribosomal DNA restriction analysis (ARDRA) and sequencing the represented ARDRA patterns. Meanwhile, the newly designed primer sets and a previously reported primer set were compared, and the results showed that the newly developed primer set SA/429f-933r could detect a larger spectrum (90%) of Sphingomonas strains with higher specificity. Despite the superiority of primer set SA/429f-933r in specifically detecting Sphingomonas from contaminated soils, we cannot blink the fact that different primer sets preferentially amplified different dominant species. Therefore, two or more primer sets are recommended for evaluating the diversity and population structure of genus Sphingomonas. Additionally, a proportion (9.7%) of the cloned sequences discovered in this study were different from known Sphingomonas sequences, suggesting that new Sphingomonas sequences might present in soils from Shenfu irrigation zone.

IRRIGATION AND CLIMATE ZONE TRIALS OF PERENNIAL PLANTS FOR SUSTAINABLE LANDSCAPES

Unstable water supplies in the Western U.S. have become more uncertain due to increasingly drier winters and rising urban populations, and chemical laden runoff from over-watered urban landscapes threatens the health of waters that receive the runoff. In California, this has led to regulations on landscape planning and installation that require knowledge of plant water requirements and the use of water-conserving plants to balance turf water needs. However, there is very little research-based data on the water use of landscape plant species. To address these issues, 2-year irrigation and climate zone trials were begun in 2005, 2007, 2009, and 2011 on landscape perennials considered by the University of California Davis Arboretum to be water-conserving, pest tolerant, and disease resistant. In each trial, ten species were evaluated on 4 levels of irrigation based on reference evapotranspiration (ET0), the estimated amount of water loss from a reference crop. Six replicates of each species and treatment were planted and established on regular irrigation (80% of ET0) the first year. The following May through October they received an irrigation treatment at 20, 40, 60, or 80% of ET0. Monthly measurements and qualitative evaluations were made to assess differences between treatments. Many of the same plants were also placed in demonstration gardens in different climate zones across California where UC Master Gardeners evaluated their performance. In many cases, there were no significant differences between irrigation treatments in either plant growth or quality, while a few species showed slight differences in one or both areas. The plant water use data being generated in these trials is helping support the necessary transition to sustainable gardens in summer-dry Mediterranean climates.

Water Use in the Irrigation Zone and Current Environmental Challenges

This article focuses on the problems of irrigation water use in the Kur – Araz lowland of the Azerbaijan Republic. Based on the analysis of the current condition of the irrigation management, it has been proposed the ways of its improvement, taking into account the peculiarities of arid zones of the country with consideration of the ongoing global climate changes and connected with the latter the necessity of optimization of water resources use and environmental protection of the irrigated areas. Importance of climate changes’ consideration in the process of reconstruction and new construction of waterwork facilities in order to ensure the condition for the sustainable irrigation systems operation, allowing improving water use efficiency through the rational use of the available water resources and achieving of the high cropyield has been substantiated.

A framework for the use of decision-support tools at various spatial scales for the management of irrigated agriculture in West-Africa

The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades in a typical theater play of anarchistic water management. With its 1800 km2, this small watershed holds the second largest city of Burkina Faso (Bobo-Dioulasso), a former State ran irrigated rice scheme and several informal agricultural zones. Despite the abundance on water resources, most water users find themselves regularly facing to water shortages due to an increase in population and low irrigation efficiencies. Local stakeholders are hence in need of easy-to-use and low-cost decision support tools for the monitoring and exploitation of the water resources at different spatial and user levels. A top-to-bottom string of adapted water management tools has been successfully installed to tackle the problems: from watershed (top) to field level (bottom), passing by the 1200 ha irrigation scheme. Land use maps have been derived from time-series of free satellite images. Combined with data from a network of hydrologic gauging stations, regional water use maps were established. SIMIS was put in place for the public-private management of the regions irrigated rice scheme. Day to day water use on irrigated plots was followed by soil humidity and crop canopy measurements. A simple field-cropwater balance model Aqua Crop was used by extension workers to draft optimal irrigation charts. Each tool was applied independently, requiring only limited data; but their combined results contributed to an improved integrated water management.

The status of natural radioactivity and heavy metals pollution on soil at Assiut Zone in Central Upper-Egypt

Context: To examine the status of the environmental quality of the soils in Assiut zone in central Upper-Egypt, investigation was carried out to determine the concentration of natural radionuclides (radium [ 226 Ra], thorium [ 232 Th] and 40 K) and the contents of eight heavy metals (Cd, Pb, Ni, Fe, Mn, Cr, Cu, and Zn). Materials and Methods: The measurements of concentration of natural radionuclides were carried out by using the gamma spectrometry (NaI (Tl); 3× 3). Results: The results indicate that the soil samples' radioactivity concentrations of 226 Ra, 232 Th, and 40 K were ranging from 10.4 ± 0.5 to 19 ± 1 Bq/kg; 6 ± 0.3-21 ± 3 Bq/kg and 103.6 ± 5-221 ± 10 Bq/kg respectively. The typical radiation doses (D o ), the external hazard index (H ex ) and annual effective dose rate values for the corresponding samples were also estimated. The concentration of heavy metals was measured by using the atomic absorption spectrometry method. Data were analyzed by using the statistical methods. The representative H ex values for the corresponding samples were also estimated. Generally, heavy metals and major elements concentration of the sediments were found decrease in sequence of Fe > Mg > pb > Zn > Cr > Cu > Ni > Cd. In some locations, the concentration for the investigated heavy metals exceeds the permissible limits recommended by the Canadian Environmental Quality Guidelines. The highest concentration of the most heavy metals (Cd, Pb, Ni, Cr, and Zn) was found in Arab Al-Madabegh region; the sewage irrigated zone. Whereas, the lowest ones was found in the not irrigated lands, which considered as a reference point of analyses. Conclusion: The maximum admitted concentrations of toxic heavy elements in the sensitive areas revealed to be exceed from three to thirty times than the non-irrigated zone.

The Transnational dimensions of Mexican irrigation, 1900-1950

In the growing field of Mexican water history, the influence of foreign people and ideas has scarcely been recognized. The transnational dimensions of this history, however, are strong and manifold, and this article outlines an avenue of research on the topic. Commercial agriculture in the Southwest US was a model for agricultural development in Northern Mexico, and in consequence, influenced its irrigation politics. Also, engineers and engineering institutions in the two countries worked closely to carry out the model of largescale irrigation followed by the Mexican government, especially during the first decade (1926-1935) of existence of the Mexican National Irrigation Commission (the Comision Nacional de Irrigación, or CNI). In particular, the White Engineering Company, a U.S. company, played a significant role in jump-starting irrigation in Mexico. Finally, the economic viability of Mexico's new irrigated zones was linked closely to a cotton economy centered in the U.S, but which incorporated northern Mexico during and after the Revolution. By outlining this transnational water history, this article contributes to an effort to rethink and refine historical narratives about the subordination of Mexico to its northern neighbor.Key words: irrigation, northern Mexico, politics of irrigation.

An easy and low-cost method for preprocessing and matching small-scale amateur aerial photography for assessing agricultural land use in Burkina Faso

In recent decades, the Kou watershed in south-western Burkina Faso has suffered from poor water management. Despite the abundance of water, most water users regularly face water shortages because of the increase in the amount of land under irrigation. To help them achieve a more equitable allocation of irrigated land, local stakeholders need an easily managed low-cost tool for monitoring and mapping these irrigated zones. The aim of this study was to develop a fast and low-cost procedure for mosaicing and geo referencing amateur small-scale aerial photographs for land-use surveys. Sets of tens (2009) and hundreds (2007) of low-altitude aerial photographs, with a resolution of 0.4m and 0.8m, respectively, were used to create a detailed land-cover map of typical African small-scale irrigated agriculture. A commercially available stitching tool and GIS allowed geo referenced 'mono-images’ to be constructed; both mosaics were warped on a high-resolution SPOT image with a horizontal root mean square error (RMSE) of about 11m. The RMSE between the two image datasets was 2m. This approach is less sensitive to atmospheric conditions that are non-predictable in programming satellite imagery.

Identifying irrigation zones across a 7.5-ha ‘Pinot noir’ vineyard based on the variability of vine water status and multispectral images

Vine water status, yield and berry composition are variables within a vineyard. There is current interest in defining zones of similar yield and berry composition. The aim of this study was to compare two methods for identifying zones of similar yield within a 7.5-ha ‘Pinot noir’ vineyard. The two methods were based on: spatial distribution of average midday leaf water potential (ΨL) and plant cell density (PCD = near-infrared/red) which is a vegetation index. A proposal for splitting the vineyard into eight new irrigation zones was assessed. A ‘blind’ zonation based on regular polygons of equal sizes was also established as a standard for comparison. Coefficients of variation (C v) in yield for both methods were compared with that of the blind zonation. In 2006 and 2007, a k-means cluster analysis indicated that variability in ΨL was mainly effected by soil properties. In both years, the vineyard was fully irrigated (100 % ETc). The two methods did not improve yield C v for full irrigation in 2006 and 2007 compared to blind zonation. In 2009, regulated deficit irrigation (RDI) was applied resulting in higher variability in ΨL and yield. The ΨL method of zonation significantly reduced coefficient of variation under RDI but PCD method did not despite the reduction in C v by 16.7 %. We recommend irrigation zonation based on ΨL when RDI is applied.