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Abstract: BACKGROUND: Irrigation water disinfection reduces the microbial load but it might lead to the formation and accumulation of disinfection by‐products (DBPs) in the crop. If DBPs are present in the irrigation water, they can accumulate in the crop, particularly after the regrowth, and be affected by the postharvest handling such as washing and storage. To evaluate the potential accumulation of DBPs, baby lettuce was grown using irrigation water treated with electrolysed water (EW) in a commercial greenhouse over three consecutive harvests and regrowths. The impact of postharvest practices such as washing and storage on DBP content was also assessed. RESULTS: Use of EW caused the accumulation of chlorates in irrigation water (0.02–0.14 mg L−1), and in the fresh produce (0.05–0.10 mg kg−1). On the other hand, the disinfection treatment had minor impact regarding the presence of trihalomethanes (THMs) in water (0.3–8.7 μg L−1 max), and in baby lettuce (0.3–2.9 μg kg−1 max). CONCLUSIONS: Disinfection of irrigation water with EW caused the accumulation of chlorates in the crop reaching levels higher than the current maximum residual limit established in the EU legislation for leafy greens. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Nonpoint source pollution of water is an important environmental issue in Japan. In this study, water samples were collected from 12 selected sites and 4 different periods at the upper stretch of the Ayase River Basin located in Saitatma prefecture, and analyzed. The results revealed that the water in the study area was in eutrophic condition and the extent of pollution varied in different ranges depending on the sites' ambient conditions. Moreover, the growing to harvesting period of crops (mainly mid-September to late-October) showed peak-values for nitrogen/phosphorus levels in water samples. The study recommends that either a strict policy needs to be incorporated or much more care should be taken to control pollution from agricultural runoffs. [ABSTRACT FROM AUTHOR]

The Produce Safety Rule of the U.S. Food Safety Modernization Act includes restrictions on the use of agricultural water of poor microbiological quality. Mitigation options for poor water quality include the application of an irrigation-to-harvest interval of ,4 days; however, dry bulb onion production includes an extended irrigation-to-harvest interval (,30 days). This study evaluated conventional curing practices for mitigating Escherichia coli contamination in a field setting. Well water inoculated with rifampin-resistant E. coli (1, 2, or 3 log CFU/mL) was applied to onion fields (randomized block design; n=5) via drip tape on the final day of irrigation. Onions remained undisturbed for 7 days and were then lifted to the surface to cure for an additional 21 days before harvest. Water, onions, and soil were tested for presence of rifampin-resistant E. coli. One day after irrigation, 13.3% of onions (20 of 150) receiving the poorest quality water (3 log CFU/mL) tested positive for E. coli; this prevalence was reduced to 4% (6 of 150 onions) after 7 days. Regardless of inoculum level, E. coli was not detected on any onions beyond 15 days postirrigation. These results support conventional dry bulb onion curing practices as an effective strategy to mitigate microbiological concerns associated with poor quality irrigation water. [ABSTRACT FROM AUTHOR]

The main aim of this study was to explore the factors affecting optimal management of agricultural water in Hamadan’s area. The statistical population of the study included all Hamadan’s farmers. A number of 148 farmers were selected randomly through a proportional sampling method in two phases. Both questionnaire and interview techniques were used in order to collect data. The empirical and face validity of the questionnaire was verified by a panel of experts consisting of faculty members and natural resource specialists. The questionnaires’ reliability was tested by Cronbach’s Alpha technique and it was 91% (α = 0.91). In addition to quantitative methodology such as descriptive statistics and factor analysis a qualitative methodology was employed for dynamic simulation among variables through Vensim software. In this study, the factor analysis technique was used through the Kaiser-Meyer-Olkin (KMO) and Bartlett tests. From the results, four key elements were identified as factors affecting the optimal management of agricultural water in Hamedan area. These factors were institutional and legal factors, technical and knowledge factors, economic factors and social factors.

The main purpose of the study was to investigate the factors affecting the sustainable management of agricultural water in Hamedan. The study population included all wheat farmers possessing irrigated farms in Hamedan city (N=1800). Of these farmers a sample of 317 people has been selected by using randomized multi-stage sampling method. The data were collected through a questionnaire's tool with help of the interview technique. Accuracy of the questions in the questionnaire was face validated by a panel of specialists. To test the reliability of the questionnaires, the questionnaires were first given to 30 farmers and Cronbach's Alpha was calculated (Alpha=0.92) then the questionnaire was finalized. Data analyzing methods such as Multiple Regression and the coefficient of variation (CV= standard deviation /mean) were used in this study. To determine the level of sustainability of the farms Bossel method proposed for classification and grading the fields was used. The results showed that variables agronomic factors, policy factors and institutional factors were able to explain 34 percent of the dependent variable's changes (sustainable management of agricultural water). According to the results, 95.3 percent of the farmers were categorized into unsustainable group, 4.1 percent into semi-sustainable and only 0.6 percent in sustainable group.

To establish the association between microbial indicators and the presence of foodborne pathogens in irrigation water, Escherichia coli was enumerated using two quantification methods (plate counts and PMA-qPCR) and presence/absence of pathogenic microorganisms, including five strains from the Shiga toxigenic E. coli (O157:H7, O26, O103, O111 and O145) and Salmonella spp. were evaluated. The results confirmed that surface water can be considered a microbial hazard when used for irrigation. The levels of viable E. coli were very similar to those of cultivable E. coli , except for irrigation water obtained from water reservoirs. Comparison between the E. coli counts in samples positive and negative for the presence of pathogenic bacteria for the evaluated water sources identified E. coli level of 2.35 log cfu/100 mL as a cut-off able to correctly predict positive and negative samples with 93% sensitivity and 66% specificity, respectively. Thus, for the samples with levels of E. coli under 2.35 log cfu/100 mL (e.g., 2.24 log cfu/100 mL) there was a 90% probability that the samples were not contaminated with pathogenic microorganism in locations with similar prevalence. E. coli levels in irrigation water were affected by the ambient temperature confirming that water source and climate conditions should be taken into account by growers when designing a sampling program and the frequency of the monitoring to make a better and more efficient use of their resources. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to identify effective factors on optimum agricultural water management based on opinions of farmers in Amlash, Guilan Province. The research design of the study was a descriptive study. The target population of this study was the farmers of Amlash in Guilan Province. The instrument used in this study was a questionnaire whose validity was confirmed by university faculty members and agricultural experts. The estimated reliability, using Cronbach’s Alpha, was 0.936, which was an acceptable reliability. According to the F-test result, number of travels to urban area per month, family participation in farming, information access, distance between the farms and agricultural service centers, farmer-owned farmlands, and productivity system significantly affect the optimum water resource management. Results of the factor analysis revealed that based on opinions of farmers in Amlash, six factors (mechanization, technical, economic, social, knowledge and experience) affect the optimum agricultural water management. These factors account for 71.50% of variance of effective factors in optimum water resource management.

Agriculture and the eco-environment are increasingly competing for water. The extension of intensive farmland for ensuring food security has resulted in excessive water exploitation by agriculture. Consequently, this has led to a lack of water supply in natural ecosystems. This paper proposes a trade-off framework to coordinate the water-use conflict between agriculture and the eco-environment, based on economic compensation for irrigation stakeholders. A hybrid Bayesian network (HBN) is developed to implement the framework, including: (a) agricultural water shortage assessments after meeting environmental flows; (b) water-use tradeoff analysis between agricultural irrigation and environmental flows using the HBN; and (c) quantification of the agricultural economic compensation for different irrigation stakeholders. The constructed HBN is computed by dynamic discretization, which is a more robust and accurate propagation algorithm than general static discretization. A case study of the Qira oasis area in Northwest China demonstrates that the water trade-off based on economic compensation depends on the available water supply and environmental flows at different levels. Agricultural irrigation water extracted for grain crops should be preferentially guaranteed to ensure food security, in spite of higher economic compensation in other cash crops’ irrigation for water coordination. Updating water-saving engineering and adopting drip irrigation technology in agricultural facilities after satisfying environmental flows would greatly relieve agricultural water shortage and save the economic compensation for different irrigation stakeholders. The approach in this study can be easily applied in water-stressed areas worldwide for dealing with water competition. [ABSTRACT FROM AUTHOR]

Based on stochastic nonparametric envelopment of data, this paper estimates the shadow prices of agricultural water and the technical efficiencies, using an input-output data of 30 provincial units in Mainland China from 2002 to 2012. The results show that the average shadow price estimates for agricultural water range between 2.57 yuan/m 3 and 3.88 yuan/m 3 ; the estimated price elasticity of agricultural water is 0.12, and that improving technical efficiencies of the agricultural sector has a significant effect on the water demand. That means the prospect of reducing the amount of agricultural water depends on the improvement of technical efficiency and the spread of water-saving irrigation techniques. [ABSTRACT FROM AUTHOR]

Aim The activity of chitosan microparticles ( CM) was examined using a matrix of conditions in order to assess the efficacy of CM as a mitigation against various strains of Salmonella enterica in agricultural water. Methods and Results Different concentrations of CM (0, 0·01, 0·1, 0·2, 0·3% w/v) were examined for antimicrobial activity against log vs stationary phase cells of Salmonella and at different conditions of temperature, salinity and pH. Results showed greatest activity with 0·3% CM at pH 7, 25-37°C without additional of salt. Significant reductions in Salmonella levels were also achieved in natural pond water, although decreases were reduced compared to sterile water. All serotypes were sensitive to CM, with minimal inhibitory concentrations ranging from 0·0031 to 0·0250% w/v. Phylogenic analysis of Javiana strains showed increased resistance appeared in multiple genetic lineages. Conclusion Conditions demonstrating greatest CM activity were compatible with agricultural practices. Although sensitivity to CM varied among Salmonella strains, all strains were sensitive under conditions examined in this study. Significance and Impact of the Study This research indicated that CM, a natural compound with minimal environmental impact, could be an effective alternative for mitigating Salmonella in agricultural water applications. [ABSTRACT FROM AUTHOR]

The U.S. Food and Drug Administration (FDA) has defined standards for the microbial quality of agricultural surface water used for irrigation. According to the FDA produce safety rule (PSR), a microbial water quality profile requires analysis of a minimum of 20 samples for Escherichia coli over 2 to 4 years. The geometric mean (GM) level of E. coli should not exceed 126 CFU/100 mL, and the statistical threshold value (STV) should not exceed 410 CFU/100 mL. The water quality profile should be updated by analysis of a minimum of five samples per year. We used an extensive set of data on levels of E. coli and other fecal indicator organisms, the presence or absence of Salmonella, and physicochemical parameters in six agricultural irrigation ponds in West Central Florida to evaluate the empirical and theoretical basis of this PSR. We found highly variable log-transformed E. coli levels, with standard deviations exceeding those assumed in the PSR by up to threefold. Lognormal distributions provided an acceptable fit to the data in most cases but may underestimate extreme levels. Replacing censored data with the detection limit of the microbial tests underestimated the true variability, leading to biased estimates of GM and STV. Maximum likelihood estimation using truncated lognormal distributions is recommended. Twenty samples are not sufficient to characterize the bacteriological quality of irrigation ponds, and a rolling data set of five samples per year used to update GM and STV values results in highly uncertain results and delays in detecting a shift in water quality. In these ponds, E. coli was an adequate predictor of the presence of Salmonella in 150-mL samples, and turbidity was a second significant variable. The variability in levels of E. coli in agricultural water was higher than that anticipated when the PSR was finalized, and more detailed information based on mechanistic modeling is necessary to develop targeted risk management strategies. [ABSTRACT FROM AUTHOR]

The present work is an effort to develop an appraisal of the hydrogeochemical regime for the aquifers of Dhekiajuli, Sonitpur district, Assam, which is imperative considering: (i) excessive use of groundwater for irrigation; (ii) reported high arsenic (As) contamination; (iii) application of fertilizer is an inevitable process undergoing in this region to achieve higher yield owing to deteriorating water quality; and (iv) study area being the location of many tea estates of Assam, that export tea in many foreign countries. The highest As concentration of 44.39 µg/L was detected in this study (Bachasimalu and Sitalmari region), implying high As-contaminated aquifers being used for drinking and irrigation purposes in the area. The relative abundance pattern of major cations and anions was in the order of Na > Mg > Ca > K and HCO > Cl > SO , respectively. Majority of the samples belong to Na-K-Cl-HCO and mixed water type. Closer inspection of Piper plot reveals that a higher As value (>40 µg/L) was prevalent in HCO water type. Results of hydrogeochemical plots suggest silicate and carbonate weathering, ion exchange and anthropogenic activities to be the dominant processes governing groundwater contamination, including As which is further supported from PCA loadings. The Singri area to the east of the affected areas and adjacent to the Brahmaputra River has oxic aquifers owing to the absence of mass deposition of younger sediments, while reducing conditions prevails in the Bachasimalu and Sitalmari region. High positive correlation between As and Fe ( r = 0.83**) and a negative correlation between ORP and Fe ( r = −0.68**) further add that Fe (hydr)oxides are the direct source of As release in the affected region, the mechanism being reductive hydrolysis of such (hydr)oxides. The study implies that although groundwater is suitable for irrigation use, there is a high probability of As getting into the food chain through tea and other edible plants irrigated with As-contaminated water; thus, the area has a maximum probability of facing health hazards caused by As-contaminated groundwater. [ABSTRACT FROM AUTHOR]

Saltwater wedge intrusion often renders the quality of water from the Shinkawa River in the city of Niigata (Japan) unsuitable for agricultural use. To determine an effective and economic strategy to limit this intrusion and prevent irrigation water from contamination by seawater, we propose a countermeasure, pushing the saltwater layer outside the river through submerged flow generated by sluice gates near the river mouth. To demonstrate this effect, an in situ experiment was conducted. During that experiment, longitudinal and vertical distributions of the saltwater wedge were observed by an acoustic profiling system and electrical conductivity meters. As a result, elevation of the density interface between freshwater and saltwater was reduced by 1.04 m on average and the longitudinal extent of the saltwater wedge was withdrawn by 1.08 km seawards over about 4 h. With the intrusion extent shortened and the density interface lowered, three of five intake pumping stations could operate without risk of saltwater mixture into irrigation water, and the risk to two other intake pumping stations was reduced. We conclude that the use of the sluice gates to generate submerged flow underneath them is an effective countermeasure to limit the saltwater wedge intrusion along the Shinkawa River and preserve the agricultural water quality during irrigation season. This method may be used in other estuaries suffering from saltwater wedge intrusion. [ABSTRACT FROM AUTHOR]

This commentary argues that the recently approved contract under which the Millennium Challenge Corporation (MCC) is investing US$437 million dollars in Niger over the next five years, most of it on large-scale irrigation, is not a good investment. The paper explains why the programme is not likely to achieve the benefits anticipated. MCC had commissioned a detailed feasibility study, carried out by the authors of this paper, which strongly argued against investing in large-scale irrigation, in part because there is a poor track record for these investments in Niger, and in part because MCC has no comparative advantage in such investments. Instead, the feasibility study presented a strong case for investing in small-scale rainwater harvesting for agriculture and livestock at farm and watershed levels; and individualised small-scale irrigation for high-value nutritious crops and other water uses. The commentary concludes with suggestions on how the funds allocated for large-scale irrigation infrastructure (about US$250 million) could be reallocated to benefit a far larger number of people; and a recommendation that investors in African agricultural water management projects carry out an assessment of the performance and impacts of investment experiences over the past decade to identify lessons that could inform the next decade of investments in agricultural water management. [ABSTRACT FROM AUTHOR]

Chemical sanitizers may induce no injury (bacteria survive), sublethal injury (bacteria are injured), or lethal injury (bacteria die). The proportion of coliform bacteria that were injured sublethally by chlorine and fungicide mixed with agricultural water (pond water), which was used to dilute the pesticide solution, was evaluated using the thin agar layer (TAL) method. In pure cultures of Enterobacter cloacae, Escherichia coli, and E. coli 0157:H7 (representing a human pathogen), the percentage of chlorine-injured cells was 69 to 77% for dilute electrolyzed water containing an available chlorine level of 2 ppm. When agricultural water was mixed with electrolyzed water, the percentage of injured coliforms in agricultural water was 75%. The isolation and identification of bacteria on TAL and selective media suggested that the chlorine stress caused injury to Enterobacter kobei. Of the four fungicide products tested, diluted to their recommended concentrations, Topsin-M, Sumilex. and Oxirane caused injury to coliform bacteria in pure cultures and in agricultural water following their mixture with each pesticide, whereas Streptomycin did not induce any injury to the bacteria. The percentage of injury was 45 to 97% for Topsin-M, 80 to 87% for Sumilex, and 50 to 97% for Oxirane. A comparison of the coliforms isolated from the pesticide solutions and then grown on either TAL or selective media indicated the possibility of fungicide-injured Rahnella aquatilis, Yersinia mollaretii, and E. coli. These results suggest the importance of selecting a suitable sanitizer and the necessity of adjusting the sanitizer concentration to a level that will kill the coliforms rather than cause sanitizer-induced cell injury that can result in the recovery of the coliforms. [ABSTRACT FROM AUTHOR]

This paper introduces Israeli agricultural water price sharing system. According to Israeli agricultural water cost composition, water price sharing by farmers as well as government subsidy and its forms, the financial subsidy-based agricultural water price system has been established on the basis of the farmer' income in our country and reasonable water price sharing, thus to promote the development of water-saving agriculture in China. [ABSTRACT FROM AUTHOR]

Campylobacter species are one of the leading causes of bacterial gastroenteritis in humans worldwide. This twofold study was sought to: i) develop and optimize four single-tube multiplex PCR (mPCR) assays for the detection of six virulence ( cia B, dna J, fla A, fla B, pld A and rac R), three toxin ( cdt A, cdt B and cdt C) and one antibiotic resistance tet (O) genes in thermophilic Campylobacter spp. and ii) apply and evaluate the developed mPCR assays by testing 470 previously identified C. jejuni , C. coli and C. lari isolates from agricultural water. In each mPCR assay, a combination of two or three sets of primer pairs for virulence, antibiotic resistance and toxin (VAT) genes was used and optimized. Assay 1 was developed for the detection of dna J, rac R and cdt C genes with expected amplification sizes of 720, 584 and 182 bp. Assay 2 generated PCR amplicons for tet (O) and cdt A genes of 559 and 370 bp. Assay 3 amplified cdt B cia B, and pld A genes with PCR amplicon sizes of 620, 527 and 385 bp. Assay 4 was optimized for fla A and fla B genes that generated PCR amplicons of 855 and 260 bp. The primer pairs and optimized PCR protocols did not show interference and/or cross-amplification with each other and generated the expected size of amplification products for each target VAT gene for the C. jejuni ATCC 33291 reference strain. Overall, all ten target VAT genes were detected at a variable frequency in tested isolates of thermophilic Campylobacter spp. where cdt C, fla B, cia B, cdt B, cdt A and pld A were commonly detected compared to the fla A, rac R, dna J and tet (O) genes which were detected with less frequency. The developed mPCR assays are simple, rapid, reliable and sensitive tools for simultaneously assessing potential pathogenicity and antibiotic resistance profiling in thermophilic Campylobacter spp. The mPCR assays will be useful in diagnostic and analytical settings for routine screening of VAT characteristics of Campylobacter spp. as well as being applicable in epidemiological studies by providing information that could be related to the risk of human infection. [ABSTRACT FROM AUTHOR]

Agriculture consumes more than two thirds of the total freshwater of the planet. This issue causes substantial conflict in freshwater allocation between agriculture and other economic sectors. Regulated deficit irrigation (RDI) is key technology because it helps to improve water use efficiency. Nonetheless, there is a lack of understanding of the mechanisms with which plants respond to RDI. In particular, little is known about how RDI might increase crop production while reducing the amount of irrigation water in real-world agriculture. In this review, we found that RDI is largely implemented through three approaches: (1) growth stage-based deficit irrigation, (2) partial root-zone irrigation, and (3) subsurface dripper irrigation. Among these, partial root-zone irrigation is the most popular and effective because many field crops and some woody crops can save irrigation water up to 20 to 30 % without or with a minimal impact on crop yield. Improved water use efficiency with RDI is mainly due to the following: (1) enhanced guard cell signal transduction network that decreases transpiration water loss, (2) optimized stomatal control that improves the photosynthesis to transpiration ratio, and (3) decreased evaporative surface areas with partial root-zone irrigation that reduces soil evaporation. The mechanisms involved in the plant response to RDI-induced water stress include the morphological traits, e.g., increased root to shoot ratio and improved nutrient uptake and recovery; physiological traits, e.g., stomatal closure, decreased leaf respiration, and maintained photosynthesis; and biochemical traits, e.g., increased signaling molecules and enhanced antioxidation enzymatic activity. [ABSTRACT FROM AUTHOR]

The pressures of frequent extreme weather, water shortages and increasing food demand pose a continued challenge of maintaining the sustainable development of irrigated agricultural systems. Although rational arable land management is fundamental to alleviating these pressures, the relationship between cropping patterns and irrigation sustainability is understudied. Using the Hexi Corridor as an example, a maximum entropy machine learning model was used to determine the optimal cropping pattern based on crop suitability and to explore the impact mechanism of the optimal cropping pattern on the irrigation sustainability index (SI) from the perspective of reliability, resilience, and vulnerability. An optimal cropping pattern was conducive to sustainable irrigation and reduced irrigation water use by 21.03% from 1960 s to 2010 s with no continued agricultural expansion. Thus, the challenges of food security and sustainability for similar regions, and globally, can be met but will require major changes in cropping planning and management. [Display omitted] • Crop suitability is an important basis for determining optimal cropping patterns. • Irrigation sustainability is assessed under optimal cropping patterns. • Adjusting the cropping pattern is an effective way to alleviate water scarcity. • Sustainable irrigation development needs more attention. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical programming model for the optimal design of water networks in the agriculture. The proposed model is based on a new superstructure that includes all configurations in terms of use, reuse and regeneration of water in a field constituted by a number of croplands. The model also includes the allocation of pipelines, pumps and storage tanks in different irrigation periods. The objective function consists in maximizing the annual profit that is formed by the economic incomes owing to the crop sell minus the costs for fresh water, fertilizer, storage tanks, treatment units, piping and pumping. The proposed multi-period optimization problem is formulated as a mixed integer non-linear programming formulation, which was applied to a case study to demonstrate the economic, environmental and social benefits that can be obtained. [ABSTRACT FROM AUTHOR]

The main aim of this study was to explore the factors affecting optimal management of agricultural water in Hamadan’s area. The statistical population of the study included all Hamadan’s farmers. A number of 148 farmers were selected randomly through a proportional sampling method in two phases. Both questionnaire and interview techniques were used in order to collect data. The empirical and face validity of the questionnaire was verified by a panel of experts consisting of faculty members and natural resource specialists. The questionnaires’ reliability was tested by Cronbach’s Alpha technique and it was 91% ( α = 0.91). In addition to quantitative methodology such as descriptive statistics and factor analysis a qualitative methodology was employed for dynamic simulation among variables through Vensim software. In this study, the factor analysis technique was used through the Kaiser-Meyer-Olkin (KMO) and Bartlett tests. From the results, four key elements were identified as factors affecting the optimal management of agricultural water in Hamedan area. These factors were institutional and legal factors, technical and knowledge factors, economic factors and social factors. [ABSTRACT FROM AUTHOR]

Summary The continuous increase in global population and simultaneous decrease in good quality water resources emphasizes the need of using surface water and groundwater resources conjunctively for irrigation. The conjunctive use allows the utilization of poor quality water, which cannot be used as such for the crop production due to its harmful effect on soil and crop health. This paper presents an overview on issues and methods of the conjunctive use of surface water and groundwater resources for sustainable irrigated agriculture. The background of the conjunctive water use and its applications for the management of poor quality water and management of rising watertable are presented. The management of conjunctive water use through the computer-based models is also covered in this review. The advantages and disadvantages of the approach have been described. Conclusions are provided based on this review which could be useful for all the stakeholders. [ABSTRACT FROM AUTHOR]

The main objective of this study is to examine the factors influencing the optimal management of agricultural water in the city of Hamedan. 148 farmers who are farming in the city of the Hamedan where randomly selected as the research sample. The Data was collected via questionnaire and interview. The accuracy of the indicators and the items of the questionnaire or the face validity were confirmed by the specialists of the course. The methodology used in this study was based on a combination of qualitative and quantitative approaches including dynamic simulation using Vensim software and analytical- descriptive methods. In data analysis, different statistical methods were used (KMO value is equal to 0.848 and Bartlett amount equals 3315 that was significant at 0.01 level of significance). The results showed that from farmers' points of view, the optimal management of water is analyzable and identifiable via four factors. These factors explain more than 79.21 percent of the total variance. Finally, some pieces of advice are recommended to achieve the optimal development of water resources in Hamedan. [ABSTRACT FROM AUTHOR]

The occurrence and diversity of thermophilic Campylobacter species (C. jejuni, coli, and lari) were studied in water samples from four river basins located across Canada. These basins located in Quebec (Bras d'Henri), Alberta (Oldman), Ontario (South Nation), and British Columbia (Sumas) represented some of the most intensive farming areas in Canada for hog, beef cattle, dairy cattle, and poultry, respectively. This study analyzed 769 water samples collected from 23 monitoring sites with agricultural influence, and four reference sites with limited or no agricultural influence. Water samples were collected bi-weekly over two years and analyzed for Campylobacter using a semi-quantitative minimum probable number (MPN) enrichment protocol. Putative isolates were confirmed by genus- and species-specific multiplex polymerase chain reaction (PCR) assays. A total of 377 (49%) water samples were positive for campylobacters with 355 samples having a cell density ranging from 4 to 4000 MPN L-1. Campylobacters were more common at agricultural than reference sites in each river basin, although this difference was not significant in the Oldman and South Nation (p > 0.05). Campylobacter was significantly more common in the Bras d'Henri and Sumas (63%) compared to the South Nation (45%) and Oldman (33%) River basins (p < 0.05). C. jejuni, C. coli and C. lari were detected in each river basin, and these species occurred in 45% (n = 168), 34% (n = 128) and 19% (n = 73), of all Campylobacter positive samples, respectively. The remaining Campylobacter positive water samples without these three species (n = 67; 18%) were identified as other Campylobacter species. C. jejuni was the predominant species occurring in the Sumas, Oldman and South Nation River basins. However, in the Bras d'Henri River basin with intensive hog production, C. coli was the predominant species. This study found campylobacters to be common in some agricultural systems with intensive livestock farming activities, and different river basins could have strikingly different profiles of either C. jejuni or C. coli as the predominant waterborne thermophilic Campylobacter species. [ABSTRACT FROM AUTHOR]

Fe3O4-SiO2-C18paramagnetic nanoparticles have been synthesised and used as magnetic solid-phase extraction (MSPE) sorbent for the extraction of Zineb from agricultural aqueous samples under ultrasonic condition and quantified through a first-derivative spectrophotometric method. The produced magnetic nanoparticles were characterised by using scanning electron microscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy and zeta potential reader. The Fe3O4-SiO2-C18paramagnetic nanoparticles had spherical structures with diameters in the range of 198–201 nm. Further, MSPE was performed by dispersion of Fe3O4-SiO2-C18paramagnetic nanoparticles in a buffered aqueous solution accompanied by sonication. Next, the sorbents were accumulated by applying an external magnetic field and were washed with 4-(2-pyridylazo) resorcinol-dimethyl sulfoxide solution, for the purpose of desorbing the analyte. The extraction conditions (sample pH, washing and elution solutions, amount of sorbents, time of extraction, sample volume and effect of diverse ions), as well as Zineb-PAR first-order derivative spectra, were also evaluated. The calibration curve of the method was linear in the concentration range of 0.055–24.3 mg L−1with a correlation coefficient of 0.991. The limit of detection and limit of quantification values were 0.022 and 0.055 mg L−1, respectively. The precision of the method for 0.27 mg L−1solution of the analyte was found to be less than 3.2%. The recoveries of three different concentrations (0.27, 1.37 and 13.7 mg L−1) obtained 98.3%, 98.5% and 96.0%, respectively. The proposed Fe3O4-SiO2-C18paramagnetic nanoparticles were found to have the capability of reusing for 7.0 times. [ABSTRACT FROM PUBLISHER]

Abstract: The main purpose of this study was to identify effective factors on optimum agricultural water management based on opinions of farmers in Amlash, Guilan Province. The research design of the study was a descriptive study. The target population of this study was the farmers of Amlash in Guilan Province. The instrument used in this study was a questionnaire whose validity was confirmed by university faculty members and agricultural experts. The estimated reliability, using Cronbach’s Alpha, was 0.936, which was an acceptable reliability. According to the F-test result, number of travels to urban area per month, family participation in farming, information access, distance between the farms and agricultural service centers, farmer-owned farmlands, and productivity system significantly affect the optimum water resource management. Results of the factor analysis revealed that based on opinions of farmers in Amlash, six factors (mechanization, technical, economic, social, knowledge and experience) affect the optimum agricultural water management. These factors account for 71.50% of variance of effective factors in optimum water resource management. [Copyright &y& Elsevier]

Wuliangsuhai Lake is the largest lake in the basin of Yellow River, and is a very important irrigation and drainage system in the Hetao Irrigation Area. From 2005 and 2010, water quality trends for 21 sites in the lake were examined for 9 parameters: water temperature (WT), pH, electrical conductivity (EC), suspended solids (SS), dissolved oxygen (DO), chemical oxygen demand (COD), chlorophyll a (ChI a), total nitrogen (TN), and total phosphorus (TP). Data were statistically analyzed using Microsoft Excel 2003 and Geostatistical Analyst in Arc GIS 9.3. In temporal trends, TN changed to a larger range from 1.05 to 10.99 mg/L, and TP fluctuations ranged from 0.057 to 0.622 mg/L. Decreased trend in COD was detected from 2005 to 2008 but increased trends in COD in 2009 and 2010 were because of the change of pollution sources in the upper channel. Overall, decreased trends in ChI a and EC were detected but increased trends in SS, pH, and DO. Changes in TN, TP, and COD were mainly related to agricultural irrigation, towns' sewage, and industrial wastewater, respectively. Changes in these parameters reflect the quantity of three kinds of wastewater, to some extent. In relation to season's variability, the values of TN, TP, and COD were significantly higher in winter than in other seasons, with values of approximately 91, 160, and 39% higher, respectively. These phenomena were caused by frozen lake water in which ice in the freezing process could discharge most pollutants from its body and the water under it. This unique phenomenon can help researchers find new ideas for lake water repair. In spatial distribution, variations are mainly related to the lake water source, the Main Drainage Channel. Moreover, water quality at the outlet of the lake is much better than that of the drainage channel. The average concentrations for TN, TP, COD, and Chl a in the exit compared with the entrance, were reduced to approximately 88, 81, 40, and 85%, respectively. [ABSTRACT FROM AUTHOR]

The scarcity of water resources in Egypt has triggered the need for using different types of low-quality water. Agricultural drainage water (ADW) is considered as a strategic reserve for coping with increasing fresh water demands. In this paper, an organized and general methodology for determining the optimum reuse discharges is presented. The physical properties of a drainage network are modeled by using a developed simulation water quality model. The genetic algorithm technique is used as an optimization tool for finding the optimum ADW reuse quantities at specific points of withdrawal. The simulation-optimization process was applied twice during the summer and winter seasons. The results show that the reuse quantities represent 75.50 and 87.12% of the available ADW in the study area for summer and winter, respectively, representing 40.57 and 43.52% of seasonal canal delivery. The use of the simulation-optimization model is suitable for decision support leading to near-optimum reuse selection of ADW for irrigation. [ABSTRACT FROM AUTHOR]

For the efficient management of water resources in the target basin, this study proposed a method to improve the reliability of a long-term hydrological simulation model by applying to the model agricultural water more approximate to actual water uses (than planned water demands) through their adjustment based on the effects of small-scale hydraulic structures. To verify agricultural water uses estimated using the proposed method, they were applied to a basin management model. And then, simulated runoff at main station points was compared with measured runoff. As a result, there occurred errors with large differences from measured data, mainly, at station points where their dependency on river water was high. To verify simulated return rate, return rate for a test zone was estimated, and then compared with the simulated return rate. Correlations between annual rainfall and runoff errors were analyzed. As a result, it was found that those errors were enlarged in dry years. Long-term runoff simulation analysis showed that simulated runoff came to be negative when a farming season began. This could be significantly improved using water uses adjusted to consider the effects of small-scale hydraulic structures. Also, correlation analysis quantitatively confirmed that simulated runoff after adjustment was more correlated with measured runoff than before adjustment. Finally, fitness tests for runoff simulations before and after adjustment were carried out through a residual analysis to analyze residual normality and independence. As a result, the fitness of runoff simulation after adjustment was significantly improved. [ABSTRACT FROM AUTHOR]

Abstract: Agricultural industry is directly affected by climatic conditions and changes; therefore, it is essential to understand the effects of climate change on agricultural water resources and to minimize negative effects on stable and sustainable crop production. In South Korea, very little research has been conducted on design water requirements (DWR) of paddy rice, which is a key part of the design and operation of agricultural water resources systems. This study aims to simulate climate data based on SRES A1B, A2 and B1 scenarios and analyze the DWR of paddy rice in South Korea using frequency analysis methods as affected by climate change. Average changes of the DWR in eight agro-climatic zones were compared to baseline period and results were −2.7% (2025s), −2.2% (2055s), and 2.5% (2085s) for the A1B scenario, −0.7% (2025s), −0.1% (2055s) and −0.7% (2085s) for the A2 scenario, and −1.0% (2025s), 2.0% (2055s) and −1.6% (2085s) for the B1 scenario. The change rates of total paddy water demand (PWD) for the three scenarios ranged between −2.7% and 2.7% for the A1B, −1.0% and 0.0% for the A2, and −1.3% and 2.4% for the B1. In both the PWD and DWR cases, the change rates were below 3%. Trends in the DWR changes of the temporal and spatial distribution were estimated from climate changes. The results of this study can be used as basic data for the development of agricultural water resources, which will contribute to the establishment of counter-measures for droughts and agricultural water policies in the future. [Copyright &y& Elsevier]

A micro liquid-liquid extraction (MLLE) flask designed for the extraction of bioavailable synthetic pyrethroids from agricultural and ground water samples is used. The method is simple, rapid, and reproducible. Extracts are analyzed off-line by reversed-phase high-performance liquid chromatography (RP-HPLC). A volume of 100 µL n-hexane is sufficient for recovery of the three pyrethroids from 100 mL water. Further clean-up is not required before injection into HPLC. The method is linear in the range of 0.5 to 1000 µg L-1. The method detection limits (MDLs) are in the range of 0.05 to 0.08 µg L-1; recoveries range from 84.7 to 94.5% and enrichment factors from 1058 to 1181. Real surface water samples were analyzed to check the applicability of the proposed method. Cypermethrin (CYP) was detected in agricultural water samples. [ABSTRACT FROM AUTHOR]

The agro-climatic resources of Cameroon are examined in light of the potential for food crop production and challenges presented by climate change. We find that the diversity of Cameroon's agro-climate offers the potential for the cultivation of a variety of food crops. This feature of Cameroonian agriculture can be used in addressing the country's adaptive capacity to climate change. However, the Savanna zones of the country, which are its most productive, are also the most vulnerable to climate change. The main climate change challenge in these Savanna zones is that of drought and associated agricultural water demand. Appropriate management strategies to address agricultural water demand can also address important problems in Cameroonian agriculture, such as the effects of climatic uncertainties in small-scale food crop production and soil nutrient depletion. To ensure the success of these management strategies, a number of obstacles may have to be addressed. [ABSTRACT FROM AUTHOR]