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PubMed2001

Regional planning for the siting of local evaporation basins for the disposal of saline irrigation drainage: development and testing of a GIS-based suitability approach.

In order to prevent salinisation of the streams of the Riverine Plain of the Murray-Darling Basin in southern Australia, evaporation basins are used to dispose of saline irrigation drainage water. Local on-farm (individual landholder) and community (shared between multiple landholders) basins are increasingly being used to prevent export of salt outside irrigation districts. There are questions regarding the availability of land suitable for these basins and their impact on the surrounding environment. We describe the use of currently available spatial data to assist in regional planning for the environmentally safe use of these basins. A GIS-based approach was developed using suitability criteria expected to minimise the risk of off-site effects of basin leakage. The criteria were proximity to surface water features, urban areas and infrastructure, water table depth and salinity, and soil hydraulic conductivity. The approach was applied to all of the major irrigation districts at 1:250,000, the scale at which data are available over the entire Riverine Plain. Confidence in well-defined parameters such as proximity to infrastructure, urban areas and surface water features was higher than for those involving interpolated point data such as water table depth, salinity, and hydraulic conductivity. Most critically, hydraulic conductivity, the most important factor for basin leakage, was found to be unreliable at this scale. Use of higher resolution data (up to 1:100,000) available for two of the irrigation districts improved confidence in both water table depth and salinity but not in hydraulic conductivity. Despite these limitations, it was found that: (i) on-farm basins can only be used on an opportunistic basis in the eastern irrigation districts, but can be widely used in the western districts; (ii) community basins can be used anywhere there is suitable land; and (iii) the results raise serious questions as to whether there is enough suitable land in the eastern districts to dispose of all of the drainage water that is produced.

Agriculture↗
PubMed1996

Irrigation Development and Its Environmental Consequences in Arid Regions of India

The present paper examines the nature and dimensions of environmental transformation induced by canal irrigation in the arid region of India. The case study pertains to the Indira Gandhi Canal comand area in Rajasthan where the density and area of vegetation cover have increased due to afforestation, and the cultivated area has expanded due to irrigation. Consequently, there has been a perceptible improvement in the structure and fertility of sandy soils, but it would require a herculean effort on the part of the canal authority and local people to reduce soil erosion and siltation in the lower parts of stage I and the entire command area of stage II. Moreover, the water table has been rising rapidly throughout the command area of stage I. About half of the command area and adjoining Ghaggar basin in Ganganagar District will be facing the danger of waterlogging by the turn of the century. The incidence of irrigation-induced alkalization is higher in the lower parts of stage I. Soil alkalinity has appeared within five years of the introduction of irrigation in the interdunal basins and is manifested as a strong salt regime or calcareous pans near surface. This calls for immediate reclamation of the affected area and prevention of its expansion by altering the strategy of irrigation development, by changing cropping patterns, and by providing soil drainage.

Journal Article↗
PubMed2004

The use of irrigation water in Bulgaria's Plovdiv region during transition.

The amount of water Bulgaria uses for irrigation sharply declined during the transition. Large sections of the existing irrigation systems were abandoned, and those still in use are hardly maintained. Crops such as wheat and barley have replaced more water-intensive crops, such as vegetables, rice, and maize. This problem has an impact on the future development of agriculture and the allocation of the country's water resources. The central argument is that land fragmentation in the wake of decollectivization and restitution contributes to the irrigation systems' abandonment. This article focuses on the institutional factors involved, but also considers additional factors that might have influenced the process. Further, it examines the causes driving these changes and analyzes their effect on irrigation. It is based on a review of the relevant legislation as well as fieldwork in 17 villages located in the Plovdiv region of Bulgaria. The article concludes that institutional settings, in addition to changes in large-scale market forces and the state enforcement mechanism, have contributed to the irrigation decline in Bulgaria.

Agriculture↗
PubMed2004

Irrigation-dependent wetlands versus instream flow enhancement: economics of water transfers from agriculture to wildlife uses.

Irrigated agriculture throughout western North America faces increasing pressure to transfer water to nonagricultural uses, including instream flows for fish and wildlife management. In an important case, increased instream flows are needed in Nebraska's Platte River for recovery of threatened and endangered fish and wildlife species. Irrigated agriculture in the Laramie Basin of southeast Wyoming is a potential water source for the effort to enhance instream flow. However, flood irrigation of hayfields in the Laramie Basin has created many wetlands, both ephemeral and permanent, over the last century. Attempting to increase Platte River instream flows by purchasing water rights or improving irrigation efficiency in the Laramie Basin would transform irrigated agriculture, causing a substantial fraction of the Laramie Basin's wetlands to be lost. A creative solution is needed to prevent the sacrifice of one ecosystem on behalf of another. A rotating short-term water-leasing program is proposed. The program allows Laramie Basin producers to contribute to instream flows while continuing to support local wetlands. Permanent wetland desiccation is prevented and regional environmental water needs are met without impairing local ecological resources. Budget analysis is used to provide an initial cost estimate for acquiring water from agriculture through the short-term leasing program. The proposed approach is more expensive than traditional programs but allows contribution to instream flows without major wetland loss. Short-term leasing is a more efficient approach if benefits from wetlands exceed the difference in cost between the short-term lease program and programs that do not conserve wetlands.

Agriculture↗
PubMed2005

Influence of arbuscular mycorrhizal fungi and kinetin on the response of mungbean plants to irrigation with seawater.

Increasing use of saline water in irrigation can markedly change the physical and chemical properties of soil. An experiment was carried out to investigate the interaction between the mycorrhizal fungus Glomus clarum, isolated from a saline soil, and kinetin on the growth and physiology of mungbean plants irrigated with different dilutions of seawater (0, 10, 20, and 30%). The growth, chlorophyll concentration and sugar content of mycorrhizal plants was greater than that of non-mycorrhizal plants under all conditions (with or without seawater). The dry weight of both mycorrhizal and non-mycorrhizal mungbean plants irrigated with 10% seawater was significantly increased by treatment with kinetin. The mycorrhizal symbiosis increased root:shoot dry weight ratio, concentrations of N, P, K, Ca and Mg, plant height, protein content, nitrogen or phosphorus-use efficiencies, and root nitrogenase, acid or alkaline phosphatase activities of seawater-irrigated mungbean plants, with little or no effect of kinetin. Kinetin treatment generally decreased chlorophyll concentration and sugar content in mycorrhizal plants as well as Na/N, Na/P Na/K, Na/Ca and Na/Mg ratios. Root colonization by G. clarum was increased by irrigation with seawater, and kinetin had no consistent effect on fungal development in roots. This study provides evidence that arbuscular mycorrhiza can be much more effective than kinetin applications in protecting mungbean plants against the detrimental effects of salt water.

Kinetin↗
PubMed2006

IWQ index: a GIS-integrated technique to assess irrigation water quality.

The irrigation water quality and the associated hazards to soil characteristics and crop yield is often a complex phenomenon that involves the combined effect of many parameters. From a management point of view, it is sometimes necessary to analyze all related parameters as a combination rather than focusing on a single isolated parameter. With this objective in mind, a new GIS-integrated tool is proposed in this study to evaluate the quality of irrigation waters with regards to potential soil and crop problems. The proposed procedure is mainly an index method that utilizes five hazard groups: (a) salinity hazard, (b) infiltration and permeability hazard, (c) specific ion toxicity, (d) trace element toxicity; and, (e) miscellaneous impacts on sensitive crops. A linear combination of these groups is formulated to form the so-called IWQ index, which is a technique that could be used to classify irrigation waters with respect to three suitability classes. The proposed technique is applied to assess the irrigation water quality of the Simav Plain located in western Anatolia, Turkey. The Simav application is implemented by using a GIS database developed for the plain. Based on the results of this application, the general groundwater quality in the surfacial aquifer is found to be fairly good and the aquifer waters are mostly suitable for irrigation purposes.

Crops, Agricultural↗
PubMed1988

Effects of irrigation with raw and differentially diluted sewage and application of primary settled sewage-sludge on wheat plant growth, crop yield, enxymatic changes and trace element uptake.

An increase in the concentration of Cu, Zn, Cr and Mn, and a decrease in the activities of aspartate amino transferase, alanine amino transferase and peroxidase were observed in the different fractions of wheat plants, following raw and differentially diluted (66% and 50%) sewage irrigation and dry primary settled sewage-sludge amendments of soils. The grain enrichment efficiencies for Cu, Zn and Mn were significantly low under all experimental conditions. On the other hand, the grain enrichment efficiency for Cr was low under all sewage irrigation conditions only. Except in the earheads of wheat plants from sludge-amended soil, catalase activities were significantly low in roots, stems and earheads of wheat plants, under all other treatment conditions investigated. The decrease in the proteinase activity was statistically significant in roots and earheads of sewage-irrigated plants; the activity in the stem was low following irrigation with raw and 66% sewage only. Proteinase activity was also significantly low in all fractions of wheat plants harvested from soil amended with 20 tonnes of sludge per hectare. The observed results appear to be due to an overall decrease in the metabolic status of the plants following sewage irrigation and sludge amendment of soils. Grain yields, however, were not reduced despite this metabolic effect.

Journal Article↗
PubMed1995

Plant uptake of fluoride in irrigation water by ladyfinger (Abelmorchus esculentus).

Because of suggestions that food is a rich source of fluoride to humans and the absence of permissible and upper limits of fluoride for irrigation water, plant uptake studies were conducted using fluoride-rich irrigation water. Ladyfinger was grown in sand and soil cultures for 18 wk and the accumulation of fluoride in various plant parts was studied. The potential for ingestion of fluoride by humans through this route was also considered. The percentage uptake was greater in sand-cultured plants than in soil-cultured plants. The root accumulates most of the fluoride supplied through irrigation water and the fruit accumulates the least. Up to 120 mg fluoride/litre of irrigation water did not harm the plants. The ingestion of fluoride by humans from plants irrigated with water containing 10 mg fluoride/litre would be 0.20 mg per 100 g ladyfinger.

Fluorides↗
PubMed2004

Does irrigated urban agriculture influence the transmission of malaria in the city of Kumasi, Ghana?

To verify the possible impact of irrigated urban agriculture on malaria transmission in cities, we studied entomological parameters, self-reported malaria episodes, and household-level data in the city of Kumasi, Ghana. A comparison was made between city locations without irrigated agriculture, city locations with irrigated urban vegetable production, and peri-urban (PU) locations with rain-fed agriculture. In the rainy as well as dry seasons, larvae of Anopheles spp. were identified in the irrigation systems of the urban farms. Night catches revealed significantly higher adult anopheline densities in peri-urban and urban agricultural locations compared to non-agricultural urban locations. Polymerase chain reaction (PCR) analysis of Anopheles gambiae sensu lato revealed that all specimens processed were A. gambiae sensu stricto. The pattern observed in the night catches was consistent with household interviews because significantly more episodes of malaria and subsequent days lost due to illness were reported in peri-urban and urban agricultural locations than in non-agricultural urban locations. In Kumasi, urban agriculture is mainly practised in inland valleys, which might naturally produce more mosquitoes. Therefore more detailed studies, also in other cities with different water sources and irrigation systems, and a better spatial distribution of sites with and without urban agriculture than in Kumasi are needed.

Adolescent↗
PubMed2004

A malaria risk analysis in an irrigated area in Sri Lanka.

Malaria in Sri Lanka is unstable and epidemic, with large spatial and temporal differences in transmission dynamics. The disease is of great public health significance and identification of underlying risk factors is important in order to use the limited resources in a cost-effective way. The International Water Management Institute (IWMI) recently launched a project of GIS-based malaria risk mapping in Sri Lanka, to investigate whether this tool could be used for epidemic forecasting and for the planning of malaria control activities. This paper presents results for the Uda Walawe region in southern Sri Lanka, an irrigated agricultural area where malaria cases were mapped at the smallest administrative level for each month over a 10-year period. Malaria incidence rates were related to land- and water-use patterns, socio-economic features, and data on malaria control interventions in a multivariate analysis. Areas of high malaria risk were characterized by: (i) higher than average rainfall, (ii) greater forest coverage; (iii) slash and burn cultivation as a predominant agricultural activity; (iv) presence of many abandoned irrigation reservoirs; and (v) poor socio-economic status. Irrigated rice cultivation areas had a lower risk of malaria than non-irrigated areas. This difference could be due to socio-economic factors related to irrigation development and/or transmission dynamics related to vector density or species composition. Our findings call for malaria control strategies that are readily adapted to different ecological and epidemiological settings. Malaria risk maps are a convenient tool for discussing targeted and cost-effective interventions with disease control personnel.

Animals↗
PubMed2005

Effect of irrigated rice agriculture on Japanese encephalitis, including challenges and opportunities for integrated vector management.

Japanese encephalitis (JE) is a disease caused by an arbovirus that is spread by marsh birds, amplified by pigs, and mainly transmitted by the bite of infected Culex tritaeniorhynchus mosquitoes. The estimated annual incidence and mortality rates are 30,000--50,000 and 10,000, respectively, and the estimated global burden of JE in 2002 was 709,000 disability-adjusted life years lost. Here, we discuss the contextual determinants of JE, and systematically examine studies assessing the relationship between irrigated rice agriculture and clinical parameters of JE. Estimates of the sizes of the rural population and population in irrigated areas are presented, and trends of the rural population, the rice-irrigated area, and the rice production are analyzed from 1963 to 2003. We find that approximately 1.9 billion people currently live in rural JE-prone areas of the world. Among them 220 million people live in proximity to rice-irrigation schemes. In 2003, the total rice harvested area of all JE-endemic countries (excluding the Russian Federation and Australia) was 1,345,000 km(2). This is an increase of 22% over the past 40 years. Meanwhile, the total rice production in these countries has risen from 226 millions of tonnes to 529 millions of tonnes (+134%). Finally, we evaluate the effect of different vector control interventions in rice fields, including environmental measures (i.e. alternate wet and dry irrigation (AWDI)), and biological control approaches (i.e. bacteria, nematodes, invertebrate predators, larvivorous fish, fungi and other natural products). We conclude that in JE-endemic rural settings, where vaccination rates are often low, an integrated vector management approach with AWDI and the use of larvivorous fish as its main components can reduce vector populations, and hence has the potential to reduce the transmission level and the burden of JE.

Agriculture↗
PubMed2005

Effects of elevated ozone on leaf delta13C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation.

Stable carbon isotope ratios (delta(13)C) and leaf conductance (g(s)) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O(3)) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative delta(13)C, and the smallest response to the treatments. Irrigation caused more negative delta(13)C, especially in H. lanatus. Irrespective of irrigation, O(3) increased delta(13)C in relationship to a decrease in g(s) in P. lanceolata and T. pratense. The strongest effect of O(3) on delta(13)C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O(3) uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O(3) uptake during dry periods when roots can reach deeper soil layers where water is not limiting.

Agriculture↗
PubMed2005

Biological treatment of clogged emitters in a drip irrigation system.

This study was conducted to investigate microbial organisms that can be used for preventing clogging in drip irrigation systems caused by biological factors. A total of 25 fungi isolate and 121 bacterial strains were isolated from water samples collected from drip irrigation systems in tomato greenhouses in the eastern Anatolia region of Turkey in the spring season of 2001. Biological clogging of emitters in a model drip irrigation system was experimentally caused by application of the microorganisms (fungi and bacteria) isolated in the study. Three antagonistic bacterial strains in the genus Bacillus spp (ERZ, OSU-142) and Burkholdria spp (OSU-7) were used for treatment of biological clogging of the emitters. The results showed that the antagonistic bacterial strains tested have the potential to be used as anti-clogging agents for treatment of emitters in drip irrigation system. This is the first study that demonstrated that antagonistic microorganisms can be utilized for treatment of clogging in drip irrigation systems.

Agriculture↗
PubMed2005

A decision support for an integrated multi-scale analysis of irrigation: DSIRR.

The paper presents a decision support designed to conduct an economic-environmental assessment of the agricultural activity focusing on irrigation called 'Decision Support for IRRigated Agriculture' (DSIRR). The program describes the effect at catchment scale of choices taken at micro scale by independent actors, the farmers, by simulating their decision process. The decision support (DS) has been thought of as a support tool for participatory water policies as requested by the Water Framework Directive and it aims at analyzing alternatives in production and technology, according to different market, policy and climate conditions. The tool uses data and models, provides a graphical user interface and can incorporate the decision makers' own insights. Heterogeneity in preferences is admitted since it is assumed that irrigators try to optimize personal multi-attribute utility functions, subject to a set of constraints. Consideration of agronomic and engineering aspects allows an accurate description of irrigation. Mathematical programming techniques are applied to find solutions. The program has been applied in the river Po basin (northern Italy) to analyze the impact of a pricing policy in a context of irrigation technology innovation. Water demand functions and elasticity to water price have been estimated. Results demonstrate how different areas and systems react to the same policy in quite a different way. While in the annual cropping system pricing seems effective to save the resource at the cost of impeding Water Agencies cost recovery, the same policy has an opposite effect in the perennial fruit system which shows an inelastic response to water price. The multidimensional assessment conducted clarified the trades-off among conflicting economic-social-environmental objectives, thus generating valuable information to design a more tailored mix of measures.

Agriculture↗
PubMed2006

Impact of irrigating rice paddies with groundwater containing arsenic in Bangladesh.

Soil and soil-water As profiles were obtained from 4 rice paddies in Bangladesh during the wet growing season (May-November), when surface water with little arsenic is used for irrigation, or during the dry season (January-May), when groundwater elevated in arsenic is used instead. In the upper 5 cm of paddy soil, accumulation of 13+/-12 mg/kg acid-leachable As (n=11) was observed in soil from 3 sites irrigated with groundwater containing 80-180 microg/L As, whereas only 3+/-2 mg/kg acid-leachable As (n=8) was measured at a control site. Dissolved As concentrations averaged 370+/-340 microg/L (n=7) in the upper 5 cm of the soil at the 3 sites irrigated with groundwater containing 80-180 microg/L As, contrasting with soil water As concentrations of only 18+/-7 microg/L (n=4) over the same depth interval at the control site. Despite the accumulation of As in soil and in soil water attributable to irrigation with groundwater containing elevated As levels, there is no evidence of a proportional transfer to rice grains collected from the same sites. Digestion and analysis of individual grains of boro winter rice from the 2 sites irrigated with groundwater containing 150 and 180 microg/L As yielded concentrations of 0.28+/-0.13 mg/kg (n=12) and 0.44+/-0.25 mg/kg (n=12), respectively. The As content of winter rice from the control site was not significantly different though less variable (0.30+/-0.07; n=12). The observations suggest that exposure of the Bangladesh population to As contained in rice is less of an immediate concern than the continued use of groundwater containing elevated As levels for drinking or cooking, or other potential consequences of As accumulation in soil and soil-water.

Agriculture↗
PubMed2006

Effect of irrigation on the survival of total coliforms in three semiarid soils after amendment with sewage sludge.

Sewage sludges are increasingly used in soil amendment programmes, although not without risk since they contain, among other potential hazards, high concentrations of total coliform bacteria. In this paper we have studied the effect of irrigation on the survival of total coliforms in three semiarid degraded soils with different agricultural practices. Fresh sewage sludge was added at 50 g kg(-1) soil, and incubated in both the presence and absence of irrigation. The absence of irrigation led to a sharp decrease in the number of total coliforms in all soils, with the bacteria disappearing in 40 days. Irrigation produced a substantial initial increase in the number of coliforms in the three soils, although after 80 days there was none growing in any of the soils. The results showed that there were significant differences in the survival of coliform bacteria due to the presence or absence of irrigation.

Agriculture↗
PubMed2004

Municipal-treated wastewater reuse for plant nurseries irrigation.

Results of an experiment aimed at assessing the possibility of reusing reclaimed wastewater for nursery ornamental plants are presented. Tests were carried out in Pistoia (Italy). A pilot plant for tertiary treatment (filtration and peracetic acid + UV disinfection) of the local wastewater treatment plant (WWTP) effluent was set up. An experimental plot with six containerized ornamental species was irrigated with the tertiary effluent and growth and physiological parameters were monitored. A control plot irrigated with fertigated water (nutrient-enriched groundwater) was also set up in order to compare the plants response to different kinds of irrigation water. The refinery treatment by filtration and disinfection with Peracetic Acid (PAA) and UV together was very effective in bacteria removal. The value of 2 MPN of Total Coliforms in 100 ml set by Italian law (until June 2003) for unrestricted irrigation was constantly satisfied. Agronomic results indicate no major limitations to the use of a tertiary effluent as an irrigation source in an ornamental plant nursery. The nutrient content of the tertiary effluent was able to maintain good plant growth as well as fertigated water for most of the tested species.

Agriculture↗
PubMed2006

Long-term changes in pollutant load outflows and purification function in a paddy field watershed using a circular irrigation system.

A long-term investigation on the water quality and hydrology was carried out for 8 years and 7 months (from October 1991 to April 2000) in a paddy field watershed using a circular irrigation system. The annual amount of rainfall ranged from 1270 to 2226 mm and it was found that the amount of irrigation water tended to decrease as rainfall increased. Phosphorus and chemical oxygen demand (COD) concentrations tended to decrease with the river flowing down, whereas nitrogen concentrations showed no significant difference. The annual outflow loads (sum of the net-outflow load during irrigation periods and the outflow load during non-irrigation periods) of total nitrogen (T-N), total phosphorus (T-P), and COD ranged from 13.6 to 75.3 kg ha(-1)yr(-1), -3.55 to 2.21 kg ha(-1)yr(-1), and -24.7 to 48.5 kg ha(-1)yr(-1), respectively. The negative values for T-P and COD loads indicated that the study watershed performed a purification function. The change in annual pollutant loads was primarily attributed to the amount of hydrological water volumes (the annual amount of rainfall or that of rainfall plus irrigation water) for T-N and COD loads and partially for T-P load. In addition, the purification function was related to the hydraulic retention time, and the study watershed allows sufficient retention for pollutant purification for phosphorus and COD contents and partially for nitrogen content.

Agriculture↗