Dissertations / Theses on the topic 'Soil irrigation'
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1
Martin, E. C., S. Husman, R. Wegener, P. Brown, K. Johnson, and L. Schnakenberg. "Determining Soil Moisture for Irrigation Management." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/210311.
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One key component in good irrigation management is the measurement of soil moisture to help determine when to irrigate. In this study, resistance blocks and tensiometers were compared to neutron probe readings to assess how well these devices followed soil moisture and whether the resistance blocks and /or tensiometers could be used to schedule irrigation in cotton production. The resistance blocks were placed at 6, 18, and 30 inches. Tensiometers were placed at 18 and 30 inches. The readings from the resistance blocks and tensiometers were compared to neutron probe readings taken at 6, 18, and 30 inches. The resistance blocks compared well with the neutron probe readings at the 6 inch and 30 inch depth. At the 18 inch depth, there was much scatter in the data. The tensiometers also showed good comparisons at 30 inches and poor comparisons at 18 inches.
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Silvertooth, Jeffrey C. "Soil Management and Soil Testing for Irrigated Cotton Production." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/558523.
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Reviewed 06/2015; Originally published: 02/20015 pp.
In this article we will discuss various aspects of soil evaluation including physical examination, soil sampling and analysis, and soil test interpretation. We will also discuss how these approaches to soil evaluation can be incorporated into both short- and long-term management plans.
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Geremew, Eticha Birdo. "Modelling the soil water balance to improve irrigation management of traditional irrigation schemes in Ethiopia." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-05242009-121531.
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Martin, Edward C. "Methods of Measuring for Irrigation Scheduling - WHEN." College of Agriculture, University of Arizona (Tucson, AZ), 2014. http://hdl.handle.net/10150/333138.
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Revised; Originally published: 20096 pp.
Proper irrigation management requires that growers assess their irrigation needs by taking measurements of various physical parameters. Some use sophisticated equipment while others use tried and true common sense approaches. Whichever method used, each has merits and limitations. In developing any irrigation management strategy, two questions are common: “When do I irrigate?” and “How much do I apply?” This bulletin deals with the WHEN.
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Martin, E. C., K. O. Adu-Tutu, W. B. McCloskey, S. H. Husman, P. Clay, and M. Ottman. "Reduced Tillage Effects on Irrigation Management in Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/197914.
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Conservation or reduced tillage practices in cotton-based crop rotation systems were studied in field experiments initiated at Marana, Coolidge and Goodyear in 2001. Following barley cover and grain crops, soil and water management assessments were made during the 2002 cotton season at the three sites. Cover and grain crop residues and a lack of tillage prior to planting cotton or during the cotton season increased the infiltration of irrigation water into coarsetextured soils, slowed irrigation advance times, and increased the amount of irrigation water used at two of the three sites compared to conventional tillage treatments.
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Killen, Mark Albert. "A physically based analytical model to predict infiltration under surge irrigation." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184379.
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A significant advantage attributed to surge flow irrigation is that for the same volume of water applied the stream will advance farther along the furrow than with continuous flow. This potentially will reduce runoff and deep percolation which will improve uniformity and application efficiency where this advance phenomenon holds. The mechanism for improvement in advance time has generally been ascribed to surface sealing and surface layer consolidation. However, these phenomena do not satisfactorily explain improved advance times in sandy soils. Widely used infiltration equations which require the determination of empirical coefficients are unsatisfactory as predictors of infiltration conditions of intermittent wetting. The Green-Ampt model and a simple redistribution model are combined into an analytical model to predict infiltration under surge irrigation. The model results are compared to infiltration tests on soil columns of three soils of different soil textures. Also the model and the experimental results from the soil columns are compared to predictions made by two numerical solutions of the Richard's equation. One of the numerical models includes the effect of hysteresis by the use of Mualem's model to predict the variation of moisture content with potential, the other numerical model neglects the effect of hysteresis. A comparison of the analytical and the numerical models shows good agreement in their predictions for the soils and surge cycles tested. A comparison of predictions made by all three models shows good correlation to the experimental results. Although the number of tests done on the analytical model were limited it appears to be nearly as good a predictor of infiltration as the numerical models. The greatest strength of the analytical model is that while the numerical models took many hours to do a single run, the analytical model took only a few minutes. Both model and experimental results indicate that there was no reduction in infiltration rates or volumes infiltrated with intermittent as compared to continuous wetting. Thus the reduction in hydraulic gradient is not a factor in the reduced infiltration observed by others.
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Santos, Francisco Lucio dos Reis Borges Brito dos. "SOIL MOISTURE UNIFORMITY IN AN IRRIGATED FIELD." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275377.
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Nyawakira, Bernard 1955. "Evaluation of two furrow infiltration measuring methods and furrow spacings." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277171.
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The effect of furrow spacing on infiltration should be determined in order to properly design an irrigation system. The blocked furrow infiltrometer (BFI) and the flowing furrow infiltrometer (FFI) methods were investigated for this purpose in two areas upon a precision field furrow. Three irrigations were performed in each method. The initial and final soil moisture contents (before and after irrigation), the furrow cross-section (before and after irrigation), the inflow volume and the furrow water surface elevations (during irrigation) were measured in each test furrow. Cumulative infiltration and infiltration rates were determined for each irrigation. The results indicate that the FFI test furrows infiltrated more water than did the BFI test furrows for the same infiltration time. The infiltration rates were higher in the FFI test furrows than in the BFI test furrows until they approach the basic intake rate. The infiltration rates were also higher during the 0.90 m spacing tests than during the 1.80 m spacing tests. The 0.90 m spacing test furrows infiltrated more water than did the 1.80 m spacing test furrows.
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Harper, Samantha (Samantha E. ). "Real-time control of soil moisture for efficient irrigation." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111509.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2017.Cataloged from PDF version of thesis. Page 52 blank.
Includes bibliographical references (pages 31-34).
In the field of precision irrigation control, two classes of controllers have emerged - classical controllers and model based controllers. The most widely-used real-time closed-loop controller is a bang-bang controller that applies water at a predetermined rate, duration, and minimum soil moisture. Due to the ease of installation of soil moisture sensors, this technology has been installed around the world. There have been few studies on altering the controller used with this existing infrastructure. This thesis articulates a model for using a real-time proportional-integral-derivative (PID) controller to minimize water use using HYDRUS- 1D, a software package for simulating the one-dimensional movement of water, heat, and solutes in porous media, to simulate soil moisture. In a direct comparison between the two controllers, the PID controller uses less water. However, small violations of the target soil moisture and optimization of the PID parameters present the current barrier to implementation of this technology. Maintaining soil moisture at or above minimal depletion is critical to support crop health throughout a growing season. PID controllers offer a mid-point between the simplistic bang-bang controllers and the model based controllers that require large datasets, wireless network infrastructure, and robust computing systems. With proper calibration, PID controllers can be implemented in the field with the same sensors that are widely used with bang-bang controllers resulting in a reduction of water use in regions where water is scarce.
by Samantha Harper.
M. Eng.
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Lordan, Sanahuja Joan. "Irrigation and soil management strategies to improve fruit tree response in limiting soil conditions." Doctoral thesis, Universitat de Lleida, 2015. http://hdl.handle.net/10803/289501.
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La transformació de terres marginals, juntament amb un augment dels processos de degradació del sòl (p. e. salinització) estan traslladant l'agricultura a sòls més desfavorables, fet que obliga al desenvolupament de noves estratègies de maneig dels cultius. Durant els últims anys s'han introduït noves estratègies de reg, com el reg localitzat enterrat (subsurface drip irrigation, SDI) o el reg deficitari controlat, tot i que resulta necessari avaluar la seva viabilitat i sostenibilitat quan són aplicades en sòls amb propietats físiques limitants. Alhora, l'ús d'esmenes orgàniques i les tècniques d’aeració forçada estan sorgint com a mètodes de recuperació de sòls a baix cost, que podrien millorar potencialment el rendiment dels cultius en situacions desfavorables. És important estudiar els efectes d'aquestes estratègies i tècniques sobre les propietats del sòl, així com en la fisiologia dels cultius i la seva productivitat, tot i que també sobre paràmetres de qualitat d'importància creixent en el sector fructícola, com el potencial de conservació de la fruita. L'objectiu general d'aquesta tesi ha estat el d'avaluar diferents estratègies de maneig del sòl i de reg, i estudiar els seus efectes en plantacions de presseguer i nectarina en sòls amb condicions físiques limitants.La transformación de tierras marginales, junto con un aumento de los procesos de degradación del suelo (p. ej. salinización) están trasladando la agricultura a suelos más desfavorables, lo que obliga al desarrollo de nuevas estrategias de manejo de los cultivos. Durante los últimos años se han introducido nuevas estrategias de riego, como el riego localizado enterrado (subsurface drip irrigation, SDI) o el riego deficitario controlado, a pesar de que resulta necesario evaluar su viabilidad y sostenibilidad cuando son aplicadas en suelos con propiedades físicas limitantes. Al mismo tiempo, el uso de enmiendas orgánicas y las técnicas de aireación forzada están surgiendo como métodos de recuperación de suelos a bajo coste, que podrían mejorar potencialmente el rendimiento de los cultivos en situaciones desfavorables. Es de suma importancia el estudiar los efectos de estas estrategias y técnicas sobre las propiedades del suelo, así como en la fisiología de los cultivos y su productividad, aunque también sobre parámetros de calidad de importancia creciente en el sector frutícola, como el potencial de conservación de la fruta. El objetivo general de esta tesis fue el de evaluar diferentes estrategias de manejo de suelo y riego, y estudiar sus efectos en plantaciones de melocotón y nectarina en suelos con condiciones físicas limitantes.
Transformation of marginal land along with an increase of soil degradation processes (e.g. salinization) is moving the agriculture into more unfavorable soils, forcing the development of new management strategies. Subsurface drip irrigation (SDI) and deficit irrigation strategies have been widely studied although it is necessary to evaluate their feasibility and sustainability when applied in soils with limiting physical properties. At the same time, organic soil amendments and oxygation techniques are arising as low-cost soil reclamation methods that could potentially improve the crop performance under such situations. It is of paramount importance to study the effects of these strategies and techniques on soil properties as well as on crop physiology and productivity, but also on some quality parameters of growing importance in the fruit sector, such as fruit storability. The general aim of this thesis was to assess various soil management and irrigation strategies and study their effects on peach and nectarine orchards under limiting soil conditions.
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Lindberg, Niklas. "Soil fauna and global change : responses to experimental drought, irrigation, fertilisation and soil warming /." Uppsala : Dept. of Ecology and Environmental Research, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s270.pdf.
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Faraj, Mustafa Ali. "The effect on soil and sugar beet plants of irrigating polyacrylamide treated soil with saline water." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329578.
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Wraith, Jon M. "Soil Temperature Influence on Water Use and Yield Under Variable Irrigation." DigitalCommons@USU, 1989. https://digitalcommons.usu.edu/etd/1996.
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The need for efficient use of water resources has increased the importance of optimum soil water usage in agricultural systems. Soil temperature has been shown to be important in influencing the early development of many plant species. Many agricultural regions have suboptimal soil temperature regimes for plant growth, and some cultural practices have been shown to reduce near-surface soil temperatures. The seasonal influence of soil temperature on soil water extraction and aboveground and belowground plant growth under variable irrigation was investigated at the USU Greenville Farm in Logan, UT. Soil surface mulches and buried heat cables were used to modify soil temperature. A line-source sprinkler system provided a gradient of water application.
During 1987 yields were mainly influenced by irrigation. During 1988 greater soil temperature differences resulted in significant plant growth and yield responses. Soil water depletion corresponded to soil temperature treatments during the early part of the growing seasons. Depth of maximum soil water depletion was about 20 cm deeper for warm treatments. Water uptake rates of earlier-maturing plants in warm treatments were reduced later in the season, so that cumulative seasonal soil water depletion was similar for all temperature treatments. Although depth of rooting was somewhat greater under high than low irrigation during 1988, low irrigation treatments depleted soil water to greater depth. There was no interactive response of plant growth and yield or of soil water depletion to soil temperature and irrigation treatments.
Modifications were made to a computer simulation model of the soil-plant-atmosphere system in order to more mechanistically simulate plant water uptake and to include influences of soil temperature on seasonal rooting growth and soil water extraction. The model adequately simulated both the pattern and magnitude of soil temperature influences on soil water depletion, and conclusions drawn from model simulations agreed with field observations during 1987 and 1988.
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Esfandiari, Baiat Mansour, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty, and School of Agriculture and Rural Development. "Evaluation of furrow irrigation models for south-east Australia." THESIS_FSTA_ARD_EsfandiariBaiat_M.xml, 1997. http://handle.uws.edu.au:8081/1959.7/739.
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The overall objective of this study was to evaluate the performance of selected furrow irrigation models for field conditions in south-east Australia. The other important aspects which were examined during this study include: developing a methodology for estimating of infiltrating characteristics, assessing the applicability of the Manning and other similar equations for flows in furrow irrigation, investigating the variation of shape factor during irrigation developing methodology for estimation of recession time and exploring the sensitivity of the models to the input parameters. Field experiments were conducted at Walla Park in northern N.S.W. and on two selected paddocks at the University Farm, Richmond, in western Sydney,Australia, over a period of three years. The validity of the assumption that the shape factor of advancing water front during furrow irrigation varies between 0.7 and 0.8 was investigated using field data collected from irrigation events monitored in the study. It was found that the average values of the shape factor varied from 0.96 to 1.80 at Walla Park site, from 0.56 to 0.80 at Field Services unit paddock site and from 0.78 to 0.84 at Horticulture Farm paddock site. The value of shape factor was affected by uniformity of furrow cross section along the length, the value and uniformity of furrow slope, furrow length and infiltration characteristics of soil. This means it is difficult to recommend a typical value for the shape factor for a given field situation.The performance of the models for prediction of advance and recession characteristics and runoff were evaluated using different indices of performance. In general, it was found that the Walker-HD and ZI model was the most satisfactory for the field conditions encountered in this study. This finding can provide a basis for initiating work on developing design criteria and management strategies for furrow irrigation in south-east Australia.Doctor of Philosophy (PhD)
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Mzini, Loyiso Lloyd. "The effects of greywater irrigation on vegetable crops and soil." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6609.
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Research on greywater irrigation has mainly focused attention on the reuse of greywater in relation to its quality and crop biomass but not on quality of edible vegetable crops. Thus a field experiment was established at the Umtata Dam Research Station where combinations of cabbages and onions; spinaches and beetroots; and carrots and lettuce were planted in to coincide with four different planting seasons (from October 2009 to December 2010). Crops were irrigated with greywater generated from bathing and dishwashing. Greywater was collected from a number of households in the vicinity of the Umtata Dam, in the Eastern Cape Province of South Africa. In the field experiment, vegetables were planted in three plots of the same composition of soil properties and then drip irrigated separately either with greywater, potable water, or with diluted greywater at a ratio of 1:1. The greywater quality, yield, aesthetical appeal, plant chemical analysis and soil chemical analysis were measured. Irrigation from diluted greywater showed a significant increase in yield, in the head mass and in appeal of cabbages. Onion yields were significantly higher when irrigated with greywater. Spinach also obtained significantly higher yields when irrigated with greywater, however many leaves from this treatment were infested with leaf-spot disease. Beetroot yield and quality was not affected with greywater irrigation, instead yield was reduced by 47% (4.686 tons/ha). Carrots did not show any significant difference in yield and root girth, but carrots irrigated with potable water were more appealing and longer in length. Lettuce irrigated with dilute greywater was significantly more appealing than other treatments. Sodium (Na) ions were elevated in cabbage, onions and were significantly higher in the case of lettuce and carrots when irrigated with greywater. Crude protein (CP) was observed to be significantly elevated on cabbages and lettuce when irrigated with diluted greywater whereas CP of onions and carrots were significantly lower due greywater irrigation. Significant increases in iron (Fe) were observed on cabbages and spinach when irrigated with diluted greywater, whereas lettuce Fe content was significantly elevated by greywater irrigation. There was no significant difference in cadmium (Cd) caused by irrigating spinach and lettuce with greywater, also those heavy metals that were significantly higher, were within the accepted threshold leaving the conclusion that lower levels of heavy metals posed no health risks to humans. In conclusion, greywater used in this study does not appear to cause an accumulation of salts and heavy metals in plants and soil, which suggests in this instance, that greywater does not pose a threat to plants and soils.
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Ding, Guannan. "Bacterial Movement in Soil During Winter Irrigation of Reclaimed Wastewater." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1409036088.
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Mohamed, Nahla Abdel-Fattah Hemdan. "Irrigation systems." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/16977.
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In der Wintersaison 2005-2006 wurde ein Split-Split Plot-Design Feldversuch mit drei Wiederholungen für jede Behandlung von Kartoffeln, als Indikatorpflanze, unter den ariden Bedingungen der Kharga Oasis in der Westlichen Wüste von Ägypten durchgeführt. Drei Bewässerungslevel (100 %, 80 %, und 60 % of ETc) mit Tröpfchenbewässerung, zwei Mulchvarianten (Zuckerrübenabfall ohne und mit 24 ton ha-1) und 4 Kompostraten (0, 12, 24, und 36 ton ha-1) wurden getestet. Generell und als Ergebnis einer Regressionsanalyse der Versuchsvarianten ohne Kompost war die beste Variante die Tröpfchenbewässerung bei 80% ETc unabhängig ob gemulcht oder nicht gemulcht wurde. Andererseits die Variante mit 36 t Kompost und mit 24 t Mulch ergab die besten Ergebnisse bei 60% of ETc sowohl beim Ertrag und den Ertragskomponenten, bei den hydrophysikalischen Eigenschaften, bei der Bodenwasserretention, beim Wasserverbrauch, bei den Pflanzenkoeffizienten, der Wassernutzungseffizienz, der Düngernutzungseffizienz sowie beim Nettogewinn. Wird die Rate der Kompostgabe aber auf 24 ton ha-1 reduziert, die höchsten Nettogewinne bei der lokalen Vermarktung als auch signifikant beim Kartoffelexport werden erreicht.Under the arid condition of Kharga Oasis in the Western Desert of Egypt, split-split plot design field experiment with three replications for each treatment using potato as an indicator plant was carried out during the winter season 2005-2006. Three irrigation levels of water regime (100 %, 80 %, and 60 % of ETc) using drip irrigation system, two treatments of soil covering (sugar cane wastes at the rate of 0 and 24 ton /ha) and compost rates (0, 12, 24, and 36 ton ha-1) were tested. In general and as a result of the triple interaction among the studied treatments, using drip irrigation either with soil mulching or not, 80 % of ETc as a water regime was the best. On the other hand, reducing drip irrigation water level at 60% of ETc in mulched soil that was treated with 36 ton ha-1 of compost recorded the highest values yield and yield components, soil hydrophysical properties, soil water retention, water consumption, crop coefficients, water economy water use efficiency, fertilizer use efficiency, net profit. But reducing the compost rate to 24 ton ha-1 attained the highest net profit for local potato consumption and achieved the best significant net profit for exportation.
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Ottman, Michael, and Steve Husman. "Irrigation of Small Grains in Arizona." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/147018.
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Husman, S. H., M. J. Ottman, K. L. Johnson, and R. J. Wegener. "Durum Response to Soil Water Depletion Levels." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/205173.
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Research has not been conducted in Arizona to determine when to irrigate wheat based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6479, 5099, 4283, and 4145 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate that more frequent irrigations may be required than is typically practiced to optimize wheat grain yields in Arizona. This work will be repeated during the 1999-2000 growing season and the results from both years will be evaluated before general conclusions are drawn.
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Escurra, Jorge Jose. "Optimal Irrigation Management for Sloping Blocked-End Borders." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/214.
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A robust mathematical model of one-dimensional flow for sloping, blocked-end border irrigation was developed using the four-point implicit method to solve the Saint-Venant equations, the volume-balance solution method, and the implementation of new algorithms to avoid numerical instability and solution divergence. The model has the capability of successfully simulating all surface irrigation phases in blocked-end borders for a range of inflow rates (0.01 - 0.05 m3/s per m), longitudinal slopes (up to 1.00%), and border lengths (100 - 500 m). To achieve numerical stability over the specified parameter ranges, the model was divided into three parts: (1) advance-phase simulation which uses the four-point implicit solution method of the Saint-Venant equations, with an algorithm that changes the spatial and temporal weighting, in addition to an algorithm that handles the water depth profile at the blocked-end downstream boundary upon completion of the advance phase; (2) simultaneous advance-recession-phase calculations using a hybrid algorithm to solve the governing equations; and (3) recession-phase simulation using the four-point implicit method until (and if) divergence occurs, then the volume-method is applied to complete the simulation. The three parts also involve the use of computational grid management algorithms and a parabolic equation which defines the Chezy coefficient as a function of water depth. The model incorporates the downhill simplex optimization method to determine the recommended inflow rate and irrigation cutoff time, maximizing a composite irrigation efficiency (water requirement efficiency and application efficiency). Different optimum values of inflow rate and irrigation cutoff time for a range of longitudinal slopes, border lengths, and soil types were generated. Most of the optimum values are for relatively high inflow rate and rapid cutoff time. In addition, exponential relations were developed, based on the simulation results, to determine the best irrigation time for maximization of the composite irrigation efficiency for specified, non-optimal inflow rates. The exponential relations are particularly useful in practice when it is not feasible to use the optimum inflow rate due to constraints at the water source, or because of irrigation scheduling issues.
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Reyes, Javier. "EXPLORING SPATIAL AND TEMPORAL VARIABILITY OF SOIL AND CROP PROCESSES FOR IRRIGATION MANAGEMENT." UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/107.
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Irrigation needs to be applied to soils in relatively humid regions such as western Kentucky to supply water for crop uptake to optimize and stabilize yields. Characterization of soil and crop variability at the field scale is needed to apply site specific management and to optimize water application. The objective of this work is to propose a characterization and modeling of soil and crop processes to improve irrigation management. Through an analysis of spatial and temporal behavior of soil and crop variables the variability in the field was identified. Integrative analysis of soil, crop, proximal and remote sensing data was utilized. A set of direct and indirect measurements that included soil texture, electrical conductivity (EC), soil chemical properties (pH, organic matter, N, P, K, Ca, Mg and Zn), NDVI, topographic variables, were measured in a silty loam soil near Princeton, Kentucky. Maps of measured properties were developed using kriging, and cokriging. Different approaches and two cluster methods (FANNY and CLARA) with selected variables were applied to identify management zones. Optimal scenarios were achieved with dividing the entire field into 2 or 3 areas. Spatial variability in the field is strongly influenced by topography and clay content. Using Root Zone Water Quality Model 2.0 (RZWQM), soil water tension was modeled and predicted at different zones based on the previous delineated zones. Soil water tension was measured at three depths (20, 40 and 60 cm) during different seasons (20016 and 2017) under wheat and corn. Temporal variations in soil water were driven mainly by precipitation but the behavior is different among management zones. The zone with higher clay content tends to dry out faster between rainfall events and reveals higher fluctuations in water tension even at greater depth. The other zones are more stable at the lower depth and share more similarities in their cyclic patterns. The model predictions were satisfactory in the surface layer but the accuracy decreased in deeper layers. A study of clay mineralogy was performed to explore field spatial differences based on the map classification. kaolinite, vermiculite, HIV and smectite are among the identified minerals. The clayey area presents higher quantity of some of the clay minerals. All these results show the ability to identify and characterize the field spatial variability, combining easily obtainable data under realistic farm conditions. This information can be utilized to manage resources more effectively through site specific application.
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Aquino, Deodato do Nascimento. "Irrigation and sustainability of soil and water resources in the area irrigation district of baixo Acarau-Dibau-CearÃ." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5235.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoIrrigation is an essential input that has enhanced, substantially, food production and has improved economic development in arid regions. Irrigation, also, has generated negative impacts to the environment and to human health. The aim of this work was to quantify and qualify the irrigation impacts and of the climatic seasonality over soil and water resource in Irrigated District of Baixo AcaraÃ, CearÃ, Brazil. Ten points spread out over the studied area were selected as monitoring stations. Two of them were sited in irrigated fields. Samples were collected monthly from Dezember/2003 to November/2005, November/2006, March and May/2007. The samples were analyzed for: pH, electrical conductivity (EC), Ca2+, Mg2+, Na+, K+, HCO3 -, PO4 -2, Cl-, NH4 +, NO3 -, SO4 -2 and Sodium Adsorption Ratio (SAR). Soil samples were collected in two different types of land use: irrigated field and uncultivated area field. Soils samples were taken for each 50 cm until water table (7 m) was reached, during wet and irrigation seasons. Multivariate statistical method, cluster analysis, was applied to classify the shallow wells inte similar groups in relation to water quality. To identify spacial variability of Na+, Cl-, CE, PO4 -2 e NO3 - in the water table it was used a GIS platform and the software: Global Mapper 5.0, ArcGis 9.1. The geostatistic process was performed using the Surfer 7.0. According to the results the highest values of changeable bases (Ca2+, Mg2+, Na+ e K+), Cl-, SAR AND NO3 - were presented in the water of P1 (sample station 1). These values were over the acceptable limit of Class 1 defined by CONAMA (Resolution 357/05). The analyzed variables showed a high spacial variability and a low temporal variability. The used soil management in the irrigated field, where shallow wells (P3 and P4) were sited, is not contributing to the contamination or water table by salts, yet. Also, the results show have that irrigation caused the groundwater concentration of NO3âN to increase from 1.52 to 19.3 mg L-1, thereby, exceeding the standards of the World Health Organization (WHO).
A irrigaÃÃo se constitui em um importante fator que contribui para a seguranÃa alimentar e possibilita o desenvolvimento econÃmico de muitas regiÃes, principalmente Ãridas e semi-Ãridas. Entretanto, se nÃo manejar adequadamente poderà vir a acarretar danos irreversÃveis ao meio ambiente com potenciais riscos à saÃde humana. Este trabalho teve por objetivo quantificar e qualificar o efeito da irrigaÃÃo e da sazonalidade climÃtica nos recursos solo e Ãgua do Distrito Irrigado do Baixo Acaraà â DIBAU, CearÃ. Foram selecionados 10 poÃos rasos como estaÃÃes de coletas de Ãgua, dos quais 2 (dois) estÃo inseridos no perÃmetro de irrigaÃÃo. As coletas de Ãgua foram realizadas mensalmente de dezembro de 2003 a novembro de 2005, novembro de 2006, marÃo e maio de 2007. As anÃlises quÃmicas foram realizadas no LaboratÃrio de Solo e Ãgua da EMBRAPA AgroindÃstria Tropical. Foram analisados: pH, CEa, Ca2+, Mg2+, Na+, K+, HCO3 -, PPO4 -, Cl -, NH4 +, NO3 -, SO4 -2 e RAS. As coletas de solo foram efetuadas em 2 pontos amostrais inseridos nas imediaÃÃes de dois dos 10 poÃos estudados, ambas coletadas no perÃodo seco e chuvoso, a cada 50 cm de profundidade da superfÃcie atà a zona de saturaÃÃo do lenÃol freÃtico. Para se classificar os poÃos em grupos de categorias semelhantes quanto à qualidade da Ãgua empregou-se a tÃcnica de estatÃstica multivariada, analise de agrupamento, empregando-se o pacote estatÃstico SPSS 13.0. Empregou-se tambÃm a plataforma SIG e os softwares: Global Mapper 5.0, ArcGis 9.1 e o Surfer 7.0 no processamento da geoestatÃstica para determinaÃÃo da variabilidade espacial do Na+, Cl-, CE, P-PO4 - e NO3 - na Ãgua do lenÃol freÃtico; como tambÃm para determinaÃÃo da direÃÃo da linha de fluxo do lenÃol freÃtico. Pelos resultados obtidos,verifica-se que as Ãguas do P1(Alparcatas) destacam-se por apresentar os valores mais elevados das bases trocÃveis (Ca2+, Mg2+, Na+ e K+), Cl-, RAS e NO3-, concentraÃÃes sempre acima dos limites mÃximos aceitÃveis para Classe 1 da ResoluÃÃo 357/05 do CONAMA. Ocorreu uma grande variabilidade espacial entre os poÃos estudados para as variÃveis analisadas, ademais nÃo se observou variabilidade temporal. O manejo praticado nos solos onde estÃo inseridos os poÃos P4 e P5, perÃmetro irrigado, por ainda nÃo estarem contribuindo com a contaminaÃÃo de sais na Ãgua do lenÃol freÃtico do DIBAU. Jà se percebe um aumento preocupante dos teores de nitrato nas Ãguas dos poÃos influenciados pela agricultura irrigada (P4 e P5), excedendo significativamente aos limites mÃximos aceitÃveis pela ResoluÃÃo 357/05 e pela Portaria 518/2004 para consumo humano.
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Husman, Stephen H., Michael J. Ottman, R. J. Wegener, and M. T. Rogers. "Barley Response to Soil Water Depletion Levels, 2000." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204060.
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This research represents the first year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields averaged over the two varieties were 8415, 7735, 7512, and 4553 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 35% soil water depletion is optimal for barley grain yield.
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Husman, Stephen H., Michael J. Ottman, R. J. Wegener, and M. T. Rogers. "Durum Response to Soil Water Depletion Levels, 2000." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204098.
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This research represents the second year of a project to determine when to irrigate wheat based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6787, 6494, 5460, and 3067 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 50% soil water depletion or less is optimal for wheat grain yield.
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Ali, Sajjad. "Evaluation of the soil moisture sensors for irrigation scheduling of strawberries." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66964.
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Horticultural producers are in need of efficient and timely techniques for determining crop water requirements. The question of when and how much to irrigate, termed irrigation scheduling, is particularly important for high-value crops such as strawberries (Fragaria ananassa). During the growing season, irrigation scheduling decisions are influenced by climatic variables such as rainfall, temperature and humidity, which directly impact soil moisture levels. A field study was therefore conducted to evaluate two soil moisture sensors for irrigation scheduling of commercial strawberries on a farm in Simcoe, Southern Ontario. Strawberries were grown on raised beds with plastic mulch under two management practices – open field and plastic high tunnels. For each practice, two soil moisture sensors based on time domain reflectometry (TDR) were evaluated. The sensors, Campbell Scientific's water content reflectometer (WCR) and ESI's Gro-point (GP) monitored soil moisture continuously over the growing season (May to October 2007). Soil samples were collected to obtain volumetric water content as a unit of reference for the purpose of comparison and evaluation of the two sensors. Equivalent water depths (EWD) were calculated for an effective strawberry rooting depth of 0.3 m. The calculated EWDs were compared with the grower's irrigation scheduling practices. The study found that the WCR and GP reliably recorded continuous trends in soil moisture throughout the growing season. For the WCR sensor, gravimetric analyses of soil samples showed excellent correlation, resulting in R2 of 0.94 and 0.97 for the open field and plastic high tunnel, respectively. The R2 for the GP sensor was good at 0.88 for the open field but poor for the plastic high tunnels, due to a malfunctioning sensor. The EWDs for the two plots were calculated to be 699 mm for the open field and 711 mm for the plastic high tunnels. A significant finLes horticulteurs ont besoin de déterminer avec précision les besoins en eau d'irrigation des cultures. En effet, la bonne gestion de la production et l'obtention d'un meilleur rendement des fraises (Fragaria ananassa) nécessitent la planification de la quantité d'eau à apporter et le jour de l'irrigation. Le climat, la pluviométrie et la variation de la température durant le stade de croissance des plantes sont des variables importantes qui compliquent la tâche de la planification de l'irrigation. La problématique de cette étude s'inscrit dans l'optique d'évaluer l'apport de deux capteurs d'humidité du sol de type TDR (Time Domain Reflectometry) à la planification de l'irrigation des fraises à Simcoe, au sud d'Ontario. Il convient de noter que les fraises ont été cultivées avec la technique du paillis de plastique, en plein champ, ainsi qu'avec la technique du tunnel en plastique. Pour atteindre les objectifs assignés à cette étude, l'utilisation de deux capteurs de type WRC (Campbell Scientific water content reflectometer) et GP (ESI's Gro-point) a permis de suivre d'une manière continue l'humidité du sol pendant le stade de croissance (mai à octobre 2007). Aussi, des échantillons du sol ont été collectés afin d'obtenir la teneur volumique en eau. Cette dernière a été utilisée comme référence et a permis ainsi de comparer et d'évaluer les résultats obtenus à l'aide des différents capteurs. Également, nous avons calculé l'équivalent d'eau en profondeur (EEP) pour une zone racinaire des fraises de 30 cm. Ce procédé nous a permis de comparer l'EEP calculé pour les différentes pratiques d'irrigation adoptées par les producteurs. Les résultats obtenus ont démontré que le WCR et GP représentent la variabilité de l'humidité du sol pendant le stade de la croissance. Pour le capteur WCR, nous avons pu établir une corrélation très intéressante avec l'analyse
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Mbarushimana, Kagabo Desire. "Modelling the soil water balance of potatoes for improved irrigation management." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07192007-134318.
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Rethwisch, Michael D., and Miguel Torres. "Irrigation Timing Effects of Soil Trigger Applicatiions of Alfalfa Hay Yield." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/202453.
Full textAbstract:
The plant growth regulator Soil Triggrr was applied in basin flood irrigation water to the first (following previous cutting) and last irrigations of a third year stand of CUF 101 alfalfa before a late June 1995 harvest. Effect of product on yield may have been limited by pH as irrigation water pH was approximately 7.9. An increase in yield was noted with product usage, with a greater yield increase noted when applied earlier in crop cycle (first irrigation = 136 lbs hay /acre) rather than later in crop development cycle (last irrigation = 34 lbs hay /acre) when compared with the untreated check Yield from the next (July) harvest was not obtained Yield differences were not statistically different or economic for a single harvest in this experiment. Alfalfa quality was not obtained.
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Shedd, Mary L. "Irrigation of St. Augustinegrass with soil moisture sensor and evapotranspiration controllers." [Gainesville, Fla.] : University of Florida, 2008. http://purl.fcla.edu/fcla/etd/UFE0022869.
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Khair, A. "Soil-cement tiles for lining small irrigation canals in developing countries." Thesis, University of Newcastle upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380763.
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Carr, Gemma. "Water Reuse for Irrigation in Jordan : Soil Sustainability, Perceptions and Management." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511676.
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Todman, Lindsay Caroline. "Mechanisms of water transport through soil from a pervaporative irrigation system." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/39345.
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This thesis presents the results of an investigation into the transport of water through soil from a pervaporative irrigation tube. This irrigation system uses a selective polymer membrane that allows water to cross by the process of pervaporation, which releases water into the soil in vapour phase. The polymer membrane is formed into a tube, buried in the soil and filled with saline water. The selectivity of the membrane retains salt within the tube whilst water is released, so the system treats the water and distributes it for irrigation simultaneously. The distribution of water from the system, rather than the treatment efficiency, was the focus of this project. Although in the field the system will interact with the plants it irrigates, in this work, for simplicity, plants were neglected. Instead a series of laboratory experiments were conducted to quantify the flux from the pervaporative tube in different soil types and in different humidity conditions. The results of these experiments highlighted, for the first time, the significance of vapour flow and condensation in the soil during the pervaporative irrigation process. Soil types with high water sorption at low relative humidity (e.g. saline sand) had an increased amount of condensation in the soil which resulted in an increased flux from the pipe. A moisture sorption isotherm was a useful predictor of this behavior. A numerical model was then developed to simulate the experimental findings. Experimental results had demonstrated that diffusion and condensation of water vapour through the soil were significant processes hence these were the main focus of the modelling work. Liquid flow was also simulated when the water content in the soil was sufficient. To simplify the representation of the pervaporative tube it was assumed that the membrane acted as a 100% humidity boundary in the soil thus it was assumed that it was the transport of water through the soil that limited the flux of water from the pervaporative tube rather than the membrane structure itself. The similarity between the observed and simulated results supported the basis of this conceptual understanding of pervaporative irrigation. This research raises a number of further questions regarding the interaction between plants and pervaporative membranes. These include how plants might interact with vapour flows through the soil and the influence of soil salinity on the interaction between the pervaporative membrane and the plant roots.
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Liang, Baochang. "Soil organic carbon and soil nitrogen fractions in a Quebec soil as influenced by corn plant population, hybrid, irrigation and fertilization." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55697.
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Radtke, Robert N. Jr. "Boron Composition of Alfalfa in Utah as Related to Soils and Irrigation Waters." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/3662.
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Eighteen field plots at 15 locations were selected throughout the state to evaluate the status of the boron content in irrigation waters, soils, and alfalfa (Medicago sativa) plant tissue under irrigated conditions.
No boron deficiency symptoms were observed in any of the alfalfa plants at any of these locations, nor were any of the plant tissue boron levels inadequate. Only two locations were found in which the alfalfa plants exibited toxicity symptoms. These locations were along the Indian and Antelope Creeks in Duchesne County which contain high boron levels in the water. All the alfalfa and soil tested and irrigated by either Indian or Antelope Creek waters are the only ones tested and found to contain, naturally occuring, high levels of boron in Utah.
The light sandy soils were found to contain less available boron than the heavier clay soils. The sandy soil of the Grand County location at Moab showed no available soil boron, while the clayey soils in Duchesne County irrigated with high boron waters were the only soils found to contain excessive levels of available soil boron.
The application of 2.8 kilograms of boron per hectare in the form of Solubor significantly increased the available soil boron content by 19.07 percent in the Cache County plots.
The 12 alfalfa varieties grown in the Morgan and Tooele County plots showed significant differences with respect to location and tissue boron contents when the results of the two locations were combined. Overall, variety desert had the highest average boron content of 69.5 milligrams boron per kilogram and AS-49R contained the lowest boron content (Y=69.91+13.64X; R2=0.79) or the available soil boron content (Y=63.15+7.66X; R2=0.82).
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Grant, Angela. "Greenhouse gas emissions from cranberry fields under irrigation and drainage in Quebec." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123175.
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Agricultural management practices influence the fluxes of greenhouse gases by altering the physical, biological and chemical environment of the soil. Cranberry farming is of particular concern because production takes place on soils with high water tables and the fields are flooded at various times of the year. These conditions initiate reductive processes which lead to the production of greenhouse gases. Weekly dark chamber flux measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were taken in two farmed cranberry fields in Quebec over the 2012 and 2013 growing seasons. Findings show that commercial cranberry fields are not significant sources of greenhouse gases throughout most of the growing season. CO2, CH4 and N2O fluxes ranged from 1-142 CO2-C m-2 hr-1, -0.01 to 0.04 mg CH4-C m-2 hr-1, and -0.0013 to 0.0013 mg N2O-N m-2 hr-1, respectively. However, when the fields are flooded during the spring melt and for harvest, they become sources of carbon dioxide and methane. Fields that remain flooded for extended periods of time thus emit significantly more greenhouse gases than those which are flooded and drained quickly.Les pratiques de gestion agricole influencent les flux de gaz à effet de serre (GES) en modifiant l'environnent physique, biologique et chimique du sol. La production de canneberges est particulièrement affectée par ces pratiques puisqu'elle a lieu sur des sols avec une nappe phréatique élevée et dont les champs sont inondés à divers moments de l'année. Ces conditions initient des réactions d'oxydo-réduction qui conduisent à la production de GES. Durant chaque semaine, des mesures du flux de dioxide de carbone (CO2), de méthane (CH4) et d'oxyde nitreux (N2O) ont été prises à l'aide de chambres à air sombres, dans deux champs de canneberges situés près de la ville de Québec, pendant la période de croissance des plantes des saisons 2012 et 2013. Les recherches démontrent que la production commerciale des champs de canneberges n'est pas une source significative de GES. Les flux de CO2, CH4 et N2O varient entre -142 CO2-C m-2 hr-1, -0.01 à 0.04 mg CH4-C m-2 hr-1, et -0.0013 à 0.0013 mg N2O-N m-2 hr-1, respectivement. Cependant, lorsque les champs sont inondés durant le printemps, ainsi que pour la période des récoltes, ils peuvent devenir des sources de dioxide de carbone et de méthane. Les champs qui demeurent inondés pendant de longues périodes de temps émettent alors une plus grande quantité de gaz à effet de serre que ceux qui sont inondés et drainés rapidement.
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Beletse, Yacob Ghebretinsae. "The environmental impact and sustainability of irrigation with coal-mine water." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-05242009-125253.
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Cid, João Filipe Xavier. "Response of grapevine to irrigation with treated wastewater." Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19445.
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Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do PortoClimate change, population growth, industry expansion and increasing water demand in agriculture are pressuring water resources in dry, warm-climate regions, such as Mediterranean Europe. The aim of this study was to evaluate the possibility of using treated wastewater (TWW) for vineyard irrigation, as a strategy to maintain grapevine's water status within acceptable levels, while contributing to decrease the pressure on natural water resources. To achieve this goal, the effects of TWW and conventional water (CW) on grapevine and soil were compared after two years of irrigation. TWW appears to have had a significant impact on soil salinity, with TWW irrigated soil having a 10% higher salinity (VIC) than the CW irrigated one. Concerning grapevine growth rate and ecophysiology, shoot length of TWW irrigated vines was significantly lower (15%), though there were generally no differences in phenology and reflectance indexes (PRI and NDVI) between treatments. In one measurement during summer peak, though, NDVI values were significantly lower for TWW irrigated vines. Also during summer peak, berries of TWW irrigated vines were significantly darker and greener, and had higher total acidity than CW irrigated vines. Canopy traits such as exposed leaf area, total leaf area and leaf layer number did not differ between treatments, and the same occurred for grape and wood yield, suggesting that TWW had no impact on vine balance and yield. It is crucial to continue exploring the use of TWW for irrigation as an answer to drought and water scarcity, while studying its effects on crops and soil within wider time periods, to scout for long-term impacts of this practice
N/A
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Johnston, Christopher R. "Soil chemical and physical changes resulting from irrigation with coalbed natural gas co-produced water effects of soil amendments and water treatments /." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445033651&sid=10&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Khandker, Md Humayun Kabir. "Crop growth and water-use from saline water tables." Thesis, University of Newcastle Upon Tyne, 1994. http://hdl.handle.net/10443/580.
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How much water can a crop abstract from below a saline water table and how does the salinity affect yield? These questions are important because shallow groundwater may represent a substantial resource in flat, low-lying areas, but may also represent a threat to sustainability where salinity is high. A series of experiments in a glasshouse aimed to elucidate irrigation management practice under salinity conditions and to develop a root uptake model under both osmotic and matric stresses. The extraction of soil water and groundwater by lettuce and perennial ryegrass crops were measured in three instrumented lysimeters. Water table depths were 0.6,0.9 and 1.2 rn below the soil surface. The lysimeters were initially saturated with saline water (electrical conductivity 4.5 dS m- 1 for lettuce, 9.4 dS m- I for the first crop of ryegrass and 0.4,7.5 & 15.0 dS m-1 for the second crop of ryegrass) and drained until an equilibrium soil water profile was attained. Water with the same electrical conductivity was then supplied by Marione siphons to maintain the constant water table. The water table contribution was recorded and water losses from the soil profile were estimated from daily readings of soil water potential using tensiometersa; nd gypsum blocks. Solute samples were extracted periodically for salinity measurement. The cropping period of lettuce was 90 days from sowing and the lst & 2nd cropping periods of ryegrass were 223 & 215 days respectively. The first ryegrass experiment showed that the water table depth (60,90 and 120 cm) did not have significant contribution (37,36 and 36 mm) on either total soil moisture use or groundwater contribution. Similar results were found for total soil moisture use for lettuce, though the groundwater contribution varied significantly. The second ryegrass experiment showed that salinity at the water table strongly influenced total soil moisture use, but the total groundwater contribution varied only slightly. The overall crop experiments show that the groundwater contribution was within the range of 25-30% of the total water use, except for the 15 dS m7l treatment where the contribution was greater than the soil moisture use. Groundwater contribution rate was higher when the plants were subjected to more osmotic and matric stresses. Yield component data show that increasing salinity leads to a reduction in total yield, but the drymatter proportion was higher. Higher salinities occurred in the upper 15 cm of the root zone, because of the greater soil moisture depletion. Below that depth the salinization rate was smaller, because of the greater groundwater contribution in the later part of the season. There is reasonable agreement between measured and estimated (based on convective transport theory) values soil salinity. Salinities increased in the root zone by about 3-fold of initial salinity for lettuce and around 4-fold for ryegrass in the top 5 cm depth, but below 15 cm depth it was less than 2 fold. Finally, a simplified model was developed to describe the interaction of root-zone salinity and water uptake, considering salinity and water stress as additive. The model shows that the higher the root-zone salinity stress, the higher the predicted water uptake while plant uptake considered -1.5 MPa. This variation is ranged from 4 to 17% for 0.4 to 9.4 dS m-1 and 30 % for 15 dS m-1. The model was developed in a climate with low atmospheric demand, but needs testing in a more severe environment.
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Molatakgosi, Goitsemodimo. "Impact of infield irrigation management by Botswana cabbage farmers on soil salinity." Thesis, Cranfield University, Cranfield University at Silsoe, 2005. http://hdl.handle.net/1826/1224.
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Some vegetable farmers in the semi- arid Botswana are struggling or closing down
their enterprises citing the cost of irrigation and salty water as the problem.
Irrigation with water from the salt-laden underground water is known to be the main
sources of salts for arid and semi-arid agricultural land. Crops grown in saline
environments show symptoms similar to those shown by drought-affected crops
hence more irrigation is needed therefore increasing the irrigation cost. Research
from other semi arid areas shows that water with high salinity levels can be used for
irrigation without increasing soil salinity to values beyond critical levels. A lot of
studies have been done which show that the impacts of saline irrigation water
depend on the irrigation management. This study therefore aims at recommending
infield irrigation management practices to be used by cabbage farmers in Botswana
without increase in soil salinity to levels that will affect crop yield.
A survey was conducted to identify the infield irrigation management practices
presently used by cabbage farmers in Botswana. Rootzone salinity trend due to the
identified infield irrigation management was simulated for 20 years using WaSim
simulation model. Recommendations on irrigation management practices were made
for those soil salinity trends that reached critical levels.
It was realised that there are no common infield irrigation management used by
farmers. The way farmers manage infield irrigation could not be identified with the
factors involved in irrigation scheduling. Infield irrigation management by the
farmers contribute to the soil salinity increase in their fields and some of the farmers are already using saline soils. Most farmers are not aware of the saline conditions they are farming on and those who know do not know about the soil salinity measures. The study recommends a need to educate farmers on irrigation under
saline environments and also a need for farmers to include soil salinity control in
their irrigation planning.
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Memon, Nisar Ahmed. "Experiments with subsurface irrigation and drainage on a sandy soil in Quebec." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72002.
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Field experiments were conducted on St-Samuel sandy loam soil in 1982 and 1983, with eight replicates of irrigated and non-irrigated maize plots. Soil moisture regime, root density and maize yields were determined to demonstrate the effect of subsurface irrigation and drainage systems.Laboratory experiments were conducted on large and small undisturbed soil cores to determine pertinent soil properties, relating drainable volume and steady upward flux to water table depth.
A water balance model was developed and used with a stress-day-index to predict water table depth, excessive and deficit soil moisture conditions and effects on corn yield. Economic analyses were made to identify subsurface irrigation/drainage designs which optimize the profit for a corn crop.
A simple method based on first and second order moments was proposed to determine the effects of parameter uncertainty in the relationship of steady upward flux vs water table depth on subsurface irrigation/drainage design parameters.
Based on the above information, a realistic subsurface irrigation/drainage design was proposed and operational recommendations were made for an example field.
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Vasanth, Arjun. "Evaluation of Evapotranspiration-based and Soil-Moisture-based Irrigation Control in Turf." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-01252008-171457/.
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Turfgrass is a major part of the landscape in North Carolina with its acreage equal to 44% of the stateâs harvested crop acreage. Proper irrigation of residential, industrial and commercial turf areas is required to ensure healthy and acceptable turf quality. With increasing competition for water resources and better turf quality, an efficient irrigation control technology is essential in meeting the dual goals of water conservation and turf quality. The objective of the research was to compare two general types of commercially available irrigation control technologies; one based on estimates of evapotranspiration (ET) and the other based on feedback from soil moisture sensors. Water application and turf quality resulting from using these technologies were compared to results from using a standard time-based irrigation schedule. The study also incorporated the effect of irrigation frequency. The experimental area, located at North Carolina State University Lake Wheeler Turf Field Laboratories, Raleigh, North Carolina, consisted of forty 4-m x 4-m plots established to âConfederateâ tall fescue (Festuca arundinacea Schreb) using sod. There were ten treatments combining control type and watering frequency (3 technologies x 3 frequencies + 1 on-demand technology) with four replicates in a randomized complete block design. Technologies included three systems: a time-based system, a soil-moisture-based âadd-onâ system, an ET-based system each with three frequencies: once per week, twice per week and seven days per week irrigation, and a soil-moisture-based âwater on-demandâ system which was allowed to schedule irrigation everyday. Rain sensors were connected to the timer-based and ET-based systems to prevent irrigation in case of rainfall. The add-on soil-moisture-based system applied the least amount of water while the ET-based technology applied the most water averaged across frequencies. Once a week irrigation frequency applied the least amount of water, and daily irrigation frequency applied the most when averaged across all technologies. Minimally acceptable turf quality was met by all the treatments when averaged over the duration of the study period, although during the last month of the study some technologies, especially the timer-based and add-on systems had noticeably drought stressed plots. In general, the ET-based system and the water on-demand system had the best turf quality. The water on-demand system resulted in the best combination of water use efficiency and turf quality. Canopy temperatures were measured once a week and there were significant differences in canopy temperature among treatments averaged over the season. The ET system plots had the lowest canopy temperature while the add-on system plots had the highest canopy temperature. Also there was no significant difference between mean weekly reference ET estimates from an atmometer and Penman-Montieth reference ET estimates using a weather station at the site.
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Mancino, C. F., L. Salo, A. Hayes, I. Pepper, and D. M. Kopec. "The Influence of Effluent Irrigation on Specific Soil Microbial Populations and Parameters." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/215852.
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Hayes, A. R., C. F. Mancino, W. Y. Forden, D. M. Kopec, and I. L. Pepper. "Irrigation of Turfgrass with Secondary Municipal Sewage Effluent: Soil and Turf Aspects." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/216076.
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This field experiment evaluated the use of secondary municipal sewage effluent for irrigation of two turfgrass species. In April 1987 common bermudagrass (Cynodon dactylon L. Pers.) was seeded to a gravelly sandy loans soil and maintained under fairway conditions. Perennial ryegrass (Loliman perenne L.) was overseeded in the fall to maintain an actively growing turf. Plots were irrigated identically with either effluent or potable water. Soil and irrigation water samples were collected periodically and analyzed for pH, electrical conductivity (EC), sodium (Na), calcium + magnesium (Ca +Mg), bicarbonates (HCO₃), nitrogen (N), phosphorus (P) and potassium (K). Effluent water was found to contain a higher sodium absorption ratio (SAR), EC and greater concentrations of all the above elements with the exception of pH. Effluent irrigation lead to significantly lower seed germination and resulted in higher EC, Na, nitrate- nitrogen (NO₃-N), P and K concentrations in soils. Turf quality was assessed by visual evaluation under four N fertilization rates in each irrigation regime. Established effluent irrigated turf did not show signs of osmotic stress with a 15-20% leaching fraction and responded to the nutrient content of this water during periods of higher irrigation rates. However, no single fertilization rate or irrigation regime consistently produced a superior turf quality. Secondary municipal sewage effluent was used successfully for turf irrigation but the greater EC, Na and nutrient content of the water need to be considered by the turf professional making management decisions.
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Monteil, Oscar Vazquez. "Wastewater irrigation of crops : the influence of nitrogen on soil-plant interactions." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303449.
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Balkcom, Kris Brandon Mitchell Charles Clifford. "Effects of subsurface drip irrigation on chemical soil properties and cotton yield." Auburn, Ala, 2009. http://hdl.handle.net/10415/1661.
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Al-Ghawas, Samir A. "Some fertility problems associated with Kuwaiti calcareous soil and brackish irrigation water." Thesis, Bangor University, 1994. https://research.bangor.ac.uk/portal/en/theses/some-fertility-problems-associated-with-kuwaiti-calcareous-soil-and-brackish-irrigation-water(d3c74d9d-cf4e-452a-8c2c-73d98636cffe).html.
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The study was undertaken to improve phosphorus (P), iron (Fe), zinc (Zn) and manganese (Mn) availability and crop uptake in Kuwaiti calcareous soils. Field, glass-house and laboratory studies investigated the effectiveness of i) pyrophosphate (PP) mixed with orthophosphate (OP) fertilizers and ii) elemental sulphur (S') as a soil acidulent. In the field PP was incorporated with OP at a PP: OP P ratio of 0: 100,5: 95 and 10: 90 and applied at recommended agronomic P rates to Zea mays (corn) and Triticum spp (wheat) with micronutrients as subtreatments. Crop yields did not differ for all treatments receiving P probably due to high P residual levels in the soil but plant P uptake and P-tissue concentrations were significantly higher with PP treatment and Zn-tissue concentrations increased above the control treatments by 17% and 34% for the corn and wheat respectively, whereas with OP only treatments there was a slight decline in Zntissue concentrations. A further two experiments were conducted in the glass-house utilising a similar soil and experimental design to grow Zea mays and Avena sativa (oat) under distilled or brackish water irrigation regimes. PP amended treatments increased plant yields in the glass-house experiments by 15-18% and 20-25% for the corn and oats, respectively, while plant P-uptake increased by 83% and 32% when PP was incorporated with OP for the corn and oats respectively. Similarly, PP treatments stimulated higher plant Zn-uptake. In the glass-house Zn concentrations in plant tissues were higher by 24-40% for treatments with PP than with OP only. These findings were supported by NaHC03 P and DTPA-Zn soil extraction, where levels moved from "marginal" to "adequate" ranges with the inclusion of PP with OP. Generally there were no significant improvements when PP/OP ratio increased from 5 to 10%. Furthermore, brackish water irrigation had no direct influence on PP soil reaction or hydrolysis. Elemental sulphur (S') was applied in quantities that could theoretically neutralise 0,25,50,100 and 200% of the soil CaCO3 with two rates of P and micronutrient combinations in a split-split plot design. In the field experiment corn and wheat were grown as test crops, while in the glass-house corn was grown with distilled or brackish water after the soil/S' mixture was incubated at 30'C and approximate field moisture capacity for six months. The oxidation of S' to H 2SO4 did not proceed in a linear fashion; there were lower rates of S' oxidation at the high S' application, better monitored by the generated SO42 than the decline in either soil pH or CaCO3 content. Soil pH decline was moderate until soil CaCO3 content dipped below 6%. At these levels soils became acidic. The dissolution of soil CaCO3 was proportional to the S' applied, but its effective size distribution changed from coarse clay/fine silt to that of coarse silt/fine sand with the highest S' rates. This would have profound effects on its surface area and activity. The S' treatment also resulted in higher soil salinity; EC increased from 3-4 to as high as 12 dSm-1. Simultaneously there was a build up of gypsum which under SEM examination revealed that soil particle surfaces were shielded by gypsum crystals. Plants did not respond favourably to S' inclusion, and yield declined by 35% with the highest S' rates. However, at moderate rates the yield was similar to the control. Soil-P increased (NaHCO3 P extraction) at moderate levels of S' and then declined at higher rates. Extractable soil-Fe (DTPA) significantly increased only at higher S' rates, while Zn (DTPA) did not have a clear response and DTPA-Mn steadily increased even with the lowest S' rate. Plant tissue concentration and element uptake were difficult to assess in the light of declining plant growth and changed soil nutrient availability. Nevertheless S' treatment equivalent to 25% CaCO3 neutralisation maintained yield, P and Zn uptake while significantly increasing Fe and Mn uptake by 63 and 12% respectively for the field grown wheat. In none of the studies was there consistent response to micronutrient fertilisation. Furthermore, brackish irrigation did not interfere with the soil nutrient extractions or plant uptake.
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Ottman, Michael J., and Stephen H. Husman. "Barley response to soil water depletion levels at Maricopa, 2002." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203859.
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This research represents the second year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields for the 35, 50, 65, and 80% depletion levels were 8319, 7296, 5606, and 3404 lbs/acre for Baretta and 9164, 8403, 6463, and 3416 lbs/acre for Max, respectively. The yield increase averaged across varieties from irrigating at 35% rather than 50% depletion is 893 lbs/acre, which has a value of $45.54/acre assuming a grain price of $5.10/cwt. However, the cost of producing this grain is $54.33/acre due the cost of two additional irrigations ($44/acre), 30 lbs additional nitrogen per acre ($8.10/acre), and increased hauling cost ($2.23/acre). The profitability of irrigating at 35% rather than 50% depletion is improved with an increase in grain price or decrease in water cost.
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Ottman, Michael J., and Stephen H. Husman. "Durum response to soil water depletion levels at Stanfield, 2002." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203860.
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This research was conducted to test the effect of soil water depletion levels on durum productivity. An experiment was conducted at a commercial farm in Stanfield where irrigations were applied at 35, 50, or 65% depletion of plant available soil water. These soil water depletion levels were estimated from soil texture and weather data. The grain yields obtained with 35, 50, and 65% depletion were 6718, 6324, and 4752 lbs/acre, respectively. Grain protein decreased and HVAC increased by irrigating more frequently at lower depletion levels. Irrigating at 50% depletion was the most economical in this study considering irrigation costs and grain quality discounts.
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Samak, Abdel-Lateif Abdel-Wahab [Verfasser]. "Soil moisture, crop yield and soil salinity relocation under partial rootzone drying irrigation / Abdel-Lateif Abdel-Wahab Samak." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1024386198/34.
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Lindberg, Niklas. "Impact of climate change on soil fauna diversity : effects of experimental drought, irrigation, soil warming and nutrient addition /." Uppsala : Swedish Univ. of Agricultural Sciences, 2001. http://epsilon.slu.se/avh/2001/99-3576673-X.pdf.
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