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1
Brown, Peter Derek. "Optimal irrigation scheduling." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2008. http://hdl.handle.net/10092/1255.
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An optimal stochastic multi-crop irrigation scheduling algorithm was developed which was able to incorporate complex farm system models, and constraints on daily and seasonal water use, with the objective of maximising farm profit. This scheduling method included a complex farm simulation model in the objective function, used decision variables to describe general management decisions, and used a custom heuristic method for optimisation. Existing optimal schedulers generally use stochastic dynamic programming which relies on time independence of all parameters except state variables, thereby requiring over-simplistic crop models. An alternative scheduling method was therefore proposed which allows for the inclusion of complex farm system models. Climate stochastic properties are modelled within the objective function through the simulation of several years of historical data. The decoupling of the optimiser from the objective function allows easy interchanging of farm model components. The custom heuristic method, definition of decision variables, and use of the Markov chain equation (relating an irrigation management strategy to mean water use) considerably increases optimisation efficiency. The custom heuristic method used simulated annealing with continuous variables. Two extensions to this method were the efficient incorporation of equality constraints and utilisation of population information. A case study comparison between the simulated annealing scheduler and scheduling using stochastic dynamic programming, using a simplistic crop model, showed that the two methods resulted in similar performance. This demonstrates the ability of the simulated annealing scheduler to produce close to optimal schedules. A second case study demonstrates the ability of the simulated annealing scheduler to incorporate complex farm system models by including the FarmWi$e model by CSIRO in the objective function. This case study indicates that under conditions of limited seasonal water, the simulated annealing scheduler increases pasture yield returns by an average of 10%, compared with scheduling irrigation using best management practice. Alternatively expressed, this corresponds to a 20-25% reduction in seasonal water use (given no change in yield return).
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Fox, Fred Andrew 1956. "Irrigation scheduling decision support." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/288770.
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Irrigation scheduling using the soil water balance approach has been recommended to irrigators for many years. Reasonably good results are normally obtained by researchers using carefully quantified inputs. Irrigators in production agriculture may estimate inputs and then question the validity of the method when the irrigation recommendations conflict with present irrigation schedules. By associating each input with an interval representing possible bias based on the way the input was estimated, and solving the irrigation scheduling model using the intervals as inputs, the output was associated with an interval representing possible bias. This method was also used to evaluate possible bias associated with growing degree day based crop coefficient curves developed from Arizona crop consumptive use measurements. For comparison purposes, roughly estimated inputs based on irrigation system type, soil type, area weather data and available crop coefficient curves were used as default intervals. Improved input intervals consisted of observed irrigation system performance, soil property measurements, local weather data and theoretical improvements in crop coefficient curves. For surface irrigation, field observation of plant stress and soil water content showed the greatest potential to improve irrigation date predictions. For buried drip under a row crop, accuracy of the predicted daily irrigation rate was most improved by a better estimate of irrigation efficacy.
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De, Vries Tonny Tessa. "Irrigation scheduling with integer programming." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273891.
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Scherer, T., D. Slack, J. Watson, and F. Fox. "Comparison of Three Irrigation Scheduling Methods and Evaluation of Irrigation Leaching Characteristics." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204858.
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Three methods were used to schedule irrigations on replicated plots at the Maricopa Ag Center using DPL 90 cotton. The three methods were: a soil water balance model based on historic consumptive use curves, a soil water balance model based on the Modified Penman Equation and daily weather (AZMET), and infrared thermometry using the C.W.S.I. A potassium-bromide conservative tracer was applied at selected sites in the plots to evaluate leaching characteristics. The irrigation scheduling test was duplicated at the Safford Experiment Station and is presented in another report. Results from the 1988 data indicate that there was no significant difference in yield between the 3 methods. There was a significant difference in water applied; the historic consumptive-use curves was the lowest and the Penman equation method was the highest.
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Scherer, T., D. Slack, J. Watson, and F. Fox. "Comparison of Three Irrigation Scheduling Methods and Evaluation of Irrigation Leaching Characteristics." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208305.
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Three methods were used to schedule irrigations during 1989 on replicated plots at the Maricopa Ag Center using DPL 90 cotton. This is a continuation of the research initiated in 1988 using the same field The three methods were; a soil water balance model based on historic consumptive use curves, a soil water balance model based on the Modified Penman Equation and daily weather (AZMET), and infrared thermometry using the C.W.S.I. A potassium- bromide conservative tracer was applied at selected sites in the plots to evaluate leaching characteristics. The irrigation scheduling test was again duplicated at the Safford Experiment Station and is presented in another report. Results from this years data indicate that there was no significant difference in yield among the three methods. However, as in 1988 there was a significant difference in water applied with historic consumptive use (ERIE) the lowest and the Penman equation method (CHECKBOOK) the highest.
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Scherer, Tom, Don Slack, Jack Watson, and Fred Fox. "Comparison of Three Irrigation Scheduling Methods and Evaluation of Irrigation Leaching Characteristics." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208344.
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Three methods were used to schedule irrigations during the 1990 growing season on replicated plots at the Maricopa Ag Center using DPL 90 cotton. This is the final report of the research initiated in 1988. The three methods were: a soil water balance model based on historic consumptive use curves (ERIE), a soil water balance model (AZSCHED) based on the Modified Penman Equation and daily weather (AZMET), and infrared thermometry using the Crop Water Stress Index (CWSI). A potassium- bromide conservative tracer was applied at selected sites in the plots to evaluate leaching characteristics. The irrigation scheduling test was again duplicated at the Safford Experiment Station and is presented in another report. Results from this years data indicate that there was no significant difference in yield between the 3 methods. Also, there was no significant difference in the amount of applied irrigation water. The AZSCHED and ERIE methods will be developed into Extension educational tools and released for use by growers.
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Ahmed, M. "A plant analogue sensor for irrigation scheduling." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378303.
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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, Edward. "Methods of Measuring for Irrigation Scheduling -- WHEN." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009. http://hdl.handle.net/10150/147005.
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Biggs, Niel, and Lee Clark. "Comparison of Irrigation Scheduling Methods on Wheat." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/200544.
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Several improved irrigation scheduling methods are available to farmers to reduce the amount of water used while not reducing crop yield. Each scheduling method has its own advantages and disadvantages. Because of the disadvantages, farmers have been slow in adopting some of the newer irrigation scheduling methods. This study compares two improved scheduling methods, the neutron hydro probe and a simplified bookkeeping method using a personal computer, with the irrigation practices normally used by a farm manager to grow wheat. In addition to the traditional parameters of applied water and yield, the time and difficulty associated with each method were evaluated.
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Clark, Lee J., and Eddie W. Carpenter. "Wheat and Barley Irrigation Scheduling Using AZSCHED." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/201390.
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Irrigations for Aldura wheat and two varieties of barley were scheduled using AZSCHED software. Planting of the crops was delayed by adverse weather so the cropping season was compressed from normal. No statistical differences were seen between the three irrigation treatments, but it was felt that AZSCHED tracked the crop water needs during the season.
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Clark, L. J., E. W. Carpenter, T. Scherer, D. Slack, and F. Fox. "Cotton Irrigation Scheduling, Safford Agricultural Center, 1988." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204840.
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Cotton was grown using historical evapotranspiration data in the Erie method a checkbook method using real-time AZMET weather data, an infrared thermometer, and a faint manager to schedule irrigations. Yields of 4 bales per acre were recorded with no significant differences between the scheduling methods. Differences were seen in the plant growth and maturity. More refining will be done in subsequent investigations.
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Biggs, E. Niel, Lee Clark, and Laura Rose. "Scheduling Cotton Irrigation with the Neutron Probe." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219765.
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Stevens, Joseph Benjamin. "Adoption of irrigation scheduling methods in South Africa." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-05162007-173724.
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El-Husseini, Sahar Nazih. "A model for irrigation scheduling with saline water." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332592.
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Haq, Zia Ul. "Application of genetic algorithms for irrigation water scheduling." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/72987/.
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A typical irrigation scheduling problem is one of preparing a schedule to service a group of outlets. These outlets may either be serviced sequentially or simultaneously. This problem has an analogy with the classical earliness/tardiness machine scheduling problems in operations research (OR). In previous published work integer programme were used to solve such problems; however, such scheduling problems belong to a class of combinatorial problems known to be computationally demanding (NP-hard). This is widely reported in OR. Hence integer programme can only be used to solve relatively small problems usually in a research environment where considerable computational resources and time can be allocated to solve a single schedule. For practical applications meta-heuristics such as genetic algorithms, simulated annealing or tabu search methods need to be used. However as reported in the literature, these need to be formulated carefully and tested thoroughly. This thesis demonstrates how arranged-demand irrigation scheduling problems can be correctly formulated and solved using genetic algorithms (GA). By interpreting arrangeddemand irrigation scheduling problems as single or multi-machine scheduling problems, the wealth of information accumulated over decades in OR is capitalized on. The objective is to schedule irrigation supplies as close as possible to the requested supply time of the farmers to provide a better level of service. This is in line with the concept of Service Oriented Management (SOM), described as the central goal of irrigation modernization in recent literature. This thesis also emphasizes the importance of rigorous evaluation of heuristics such as GA. First, a series of single machine models is presented that models the warabandi (rotation) type of irrigation distribution systems, where farmers are supplied water sequentially. Next, the multimachine models are presented which model the irrigation water distribution systems where several farmers may be supplied water simultaneously. Two types of multimachine models are defined. The simple multimachine models where all the farmers are supplied with identical discharges and the complex multimachine models where the farmers are allowed to demand different discharges. Two different approaches i.e. the stream tube approach and the time block approach are used to develop the multimachine models. These approaches are evaluated and compared to determine the suitability of either for the irrigation scheduling problems, which is one of the significant contributions of this thesis. The multimachine models are further enhanced by incorporating travel times which is an important part of the surface irrigation canal system and need to be taken into account when determining irrigation schedules. The models presented in this thesis are unique in many aspects. The potential of GA for a wide range of irrigation scheduling problems under arranged demand irrigation system is fully explored through a series of computational experiments.
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Garrot, D. J. Jr, S. Stedman, and D. B. Benedict. "Tierra Prospera Farms CWSI Irrigation Scheduling Demonstration Test." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204860.
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Martin, E. C., E. J. Pegelow, and S. Stedman. "Comparison of Irrigation Scheduling Methods in Cotton Production." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/210291.
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Three different irrigation scheduling techniques were compared in this study; aerial infrared, hand -held infrared, and neutron moisture gage measurements. There were four treatments with three replications of each. Treatment one was scheduled using aerial infrared imaging and analyzes performed by Agrometrics, Inc. Treatment two was scheduled using a hand -held infrared gun. Irrigations for this treatment were initiated at a crop water stress index value of 0.3. Treatments three and four were scheduled using neutron probe measurements. Treatment three was irrigated at 45% depletion of the available soil water. Treatment four was irrigated at 45% depletion of the available soil water until mid-bloom, when the strategy was changed to irrigate at 35% depletion. Yield results showed no significant difference between the treatments.
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Garrot, D. J. Jr, M. W. Kilby, D. D. Fangmeier, and S. H. Husman. "Quantification of Pecan Water Stress for Irrigation Scheduling." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/215744.
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Jaria, Felix. "Irrigation scheduling strategies for tomato production in Southwestern Ontario." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116875.
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Precision irrigation scheduling is critical to improving irrigation efficiency. It is a combined technical and managerial tool that determines accurately when, how much and how often irrigation is applied to meet optimum crop response. This is particularly challenging in humid regions such as Southwestern Ontario, where soil moisture is often influenced by periodic rainfalls. The overarching goal of this three year research project was to investigate different irrigation scheduling strategies for tomato production in Leamingtion, Ontario. There were four specific objectives. The first sought to develop an optimum irrigation schedule for intensive cultivation of processing tomatoes by examining different irrigation trigger levels. Moisture triggers were expressed as a fraction of field capacity and soil tension, which are also related to soil available water content (AWC). Triggers with moisture depletion levels of ≤ 40 % (AWC) produced the higher yields. However, the best yields were obtained from the tension treatment with an upper and lower moisture threshold of -10 kPa and -30 kPa, which represented 20 to 24% depletion in AWC.The second objective sought to develop a robust protocol for implementing an irrigation scheduling. Three different types of soil moisture sensors were evaluated. The tension based senor emerged with the highest evaluation score. However, all three sensors could be used to effect irrigation scheduling. The sensor based irrigation data was subsequently compared with the Peman-Monteith model. It was found that the soil moisture treatments with a moisture depletion level of ≤ 40 % soil available water content (AWC) adequately met crop water requirements throughout the season.The third objective examined the spatio-temporal variability of soil moisture under drip irrigation in a controlled greenhouse environment. The study indicated that soil moisture content was not uniformly distributed prior to or after an irrigation event. For double row planting of tomatoes with a central drip line, a row spacing of 50 cm was adequate for planting of seedlings, due to the higher soil moisture contents within that zone. Further, due to the lack of uniform distribution of moisture in the soil profile, paired sensors (with one either side of the drip line) can provide a better estimate of soil moisture depletion for sensor based irrigation scheduling.The fourth objective investigated the nutrient dynamics along the soil profile over the growing season. Soil nutrients (P and N) were monitored at three different levels of the profile (0 to 30, 30 to 50 and 50 to 70 cm) and at the pre-planting, mid-season and end of season stages. Statistical significance in Olsen P and NO3-N was obtained both across the season and along the profile for each of the three years. The variability among treatments was not significant. The P and N concentrations at the 50 to 70 cm depths were found to be high, with the potential of being leached through the subsurface drainage system. A modification in the application of P and N can help reduce leaching of nutrients below the rooting zone. This would necessitate a split application of P and more frequent application of liquid N in smaller quantities.La planification précise de l'irrigation est critique à l'amélioration de son rendement. C'est un outil technique et de gestion qui permet d'évaluer avec précision la quantité et la fréquence d'application de l'irrigation afin de répondre à la demande pour une croissance optimale des cultures. Cette planification est particulièrement difficile dans les régions humides, comme celles du sud-ouest ontarien, où l'humidité des sols est influencée par des pluies périodiques. Le but fondamental de ce projet de recherche de trois ans était d'étudier les différentes stratégies de planification de l'irrigation pour la production de tomates à Leamington, Ontario. Il y a eu quatre objectifs spécifiques. Le premier a visé à développer une planification optimale de l'irrigation pour des conditions intensives de culture de la tomate destinée à la transformation en examinant différents facteurs déclencheurs pour l'irrigation. Le taux d'humidité, comme élément déclencheur, a été exprimé par une fraction de la capacité au champ et de la succion du sol, qui sont reliés à la réserve utile (RU) d'eau du sol. Le dispositif de déclenchement avec un appauvrissement en eau de ≤ 40% (RU) a produit les meilleurs rendements. Les meilleurs rendements ont été obtenus lors d'une tension entre les seuils critiques supérieur et inférieur d'humidité de -10 kPa et -30 kPa, ce qui représentait un appauvrissement de 20 à 24% de la RU. Le second objectif a visé le développement d'un protocole robuste pour la mise en opération d'une planification du calendrier d'irrigation. Trois différents types de capteurs de l'humidité du sol ont été évalués. Le capteur basé sur la mesure de succion est sorti gagnant avec la plus haute note d'évaluation. Cependant, les trois capteurs peuvent être utilisés avec succès pour le contrôle du calendrier d'irrigation. Les données obtenues lors de l'irrigation contrôlée par les capteurs ont été comparées avec le modèle de Peman-Monteith. Il a été démontré que les niveaux d'humidité du sol qui ont assuré un appauvrissement en eau de ≤ 40% de la réserve utile (RU) du sol en eau ont permis de remplir les besoins en eau des cultures tout au long de la saison. Le troisième objectif a examiné la variabilité spatio-temporelle de l'humidité du sol lors de l'irrigation au goutte-à-goutte dans une serre à environnement contrôlé. L'étude a montré que l'humidité du sol n'était pas distribuée uniformément et ce avant, comme après l'irrigation. Dans le cas des tomates de champ avec une ligne centrale de goutte-à-goutte, un espacement de rangée double de 50 cm fut adéquat pour le semis des jeunes pousses, grâce au plus haut taux d'humidité du sol dans cette zone. De plus, avec le manque d'uniformité de la distribution de l'humidité dans le sol, des capteurs jumelés (placés de chaque côté de la ligne goutte-à-goutte) pourraient donner une meilleure estimation de l'appauvrissement en eau du sol pour une meilleure programmation de l'irrigation contrôlée par capteur. Le quatrième objectif a étudié la cinétique des éléments nutritifs à travers le profil du sol tout au long de la saison de culture. Les éléments nutritifs du sol (P et N) ont été surveillés à différents niveaux du profil (0 à 30, 30 à 50 et 50 à 70 cm) et au moment précédant le semis, en mi-saison et en fin de saison. La signification statistique de P et N a été obtenue tout au long de la saison et selon le profil du sol et ce pour les trois années de l'étude. La variabilité entre les traitements n'a pas été significative. Les concentrations en P et N aux profondeurs de 50 et 70 cm se sont avérées élevées, avec un potentiel d'être emportées par le système de drainage souterrain. Une modification de l'application de P et N peut aider à réduire le lessivage du sol sous la zone racinaire.
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Bailey, Abby Lee Wright Amy Noelle. "Post-transplant irrigation scheduling of native deciduous shrub taxa." Auburn, Ala, 2009. http://hdl.handle.net/10415/1834.
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Clark, L. J., and E. W. Carpenter. "Wheat Irrigation Scheduling at the Safford Agricultrual Center, 1988." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/200818.
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Wheat irrigations were scheduled using two computer models and an infrared thermometer using two critical threshold values. Yields from these plots were compared with plots scheduled by the farm manager. The highest yield was obtained by the computer model using evapotranspiration data taken from the local AZMET station; the plots scheduled by the infrared thermometer (using the low threshold value) ranked a close second.
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Clark, L. J., and E. W. Carpenter. "Wheat Irrigation Scheduling at the Safford Agricultural Center, 1989." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/201075.
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Wheat irrigations were scheduled using two computer models and an infrared thermometer, using three critical threshold values. Yields from these plots were compared with plots scheduled by the farm manager. The highest yield was obtained by the computer model using evapotranspiration data taken from the local AZMET station; this corroborates results from the previous year. The crop coefficients and the irrigation model that have been developed over the past several years are very accurate for this area. The two lower threshold infrared treatments were second and third in yield and had lower water use efficiencies.
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Garrot, D. J. Jr, D. D. Fangmeier, and S. H. Husman. "Scheduling Pima Cotton Irrigations Using Infrared Thermometers." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204841.
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Plots of pima S-6 cotton were scheduled for irrigation using the Crop Water Stress Index (CWSI). Irrigations were applied when CWSI levels reached 0.08 (wet), 0.34 (medium), and 0.68 (dry) units. The medium treatment had significantly higher lint yield. Preliminary test results indicate the CWSI can be useful in irrigation-management decisions regarding pima cotton production.
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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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Pauliukevičiūtė, Grybauskienė Vilda. "Irrigation Scheduling for Norway Spruce (Picea abies (L.) Karst.) Seedlings." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20110908_114726-07715.
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The objectives of the thesis: • to analyse evapotranspiration of Norway spruce seedlings in irrigated and non-irrigated fields by applying lysimetric method; • to determine crop coefficient of spruce seedlings; • to measure dynamics of soil humidity during vegetation period; • to determine influence of irrigation regime on qualitative indices of spruce seedlings; • to determine optimal irrigation regime; • to set economic advantage of irrigation of Norway spruce seedlings.Darbo uždaviniai: • ištirti paprastosios eglės sodinukų suminį išgaravimą drėkinamuose ir nedrėkinamuose plotuose lizimetriniu metodu; • nustatyti eglės sodinukų biologinius koeficientus; • įvertinti dirvožemio drėgmės dinamiką vegetacijos laikotarpiu; • nustatyti drėkinimo režimo įtaką eglės sodinukų kokybiniams rodikliams; • nustatyti optimalų drėkinimo režimą; • nustatyti paprastosios eglės sodinukų drėkinimo ekonominį efektyvumą.
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Bockhold, Daniel. "Application of canopy temperature for irrigation scheduling in humid environments /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418005.
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Clark, L. J., and E. W. Carpenter. "Irrigation Scheduling on Barley at the Safford Ag Center, 1997." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/202475.
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An irrigation study on barley was made to determine the economical consequences of irrigating the crop when an irrigation scheduling program called for an irrigation compared to waiting 3 to 6 days for a water turn, from the ditch. The plots irrigated when the soil moisture depletion level reached 40% produced the highest yield. Yields were decreased 700 and 1000 pounds respectively for waiting 3-4 days and 6-7 days, respectively. The economics of using the pump are discussed and a chart is given to help determine a break - even point.
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Yagi, Kazuhiko 1957. "Near real-time irrigation scheduling using the Bowen ratio technique." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277106.
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The actual evapotranspiration rate for wheat at the Campus Agriculture Center (CAC) and alfalfa at the Maricopa Agricultural Center (MAC) were measured using the Bowen ratio technique for near real-time irrigation scheduling. The Bowen ratio method underestimated evapotranspiration when compared with AZMET and Penman data. There were problems with the hygrometer and the net radiometer which might have caused this underestimation. The height-fetch ratio requirement was not met, and this may have affected the data. Irrigation scheduling programs and the technique to schedule irrigation in a near real-time were developed. Irrigation programs were not field tested because of the problem with field data. Simulated data was successfully used to demonstrate its application. It was found that irrigation could be scheduled in a near real-time with the programs provided reliable data and proper data acquisition systems are used.
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Silva, Joana Sequeira dos Ramos. "Planos de gestão de rega em projectos de arquitectura paisagista." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4148.
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Mestrado em Arquitectura Paisagista - Instituto Superior de AgronomiaIrrigation is an essential factor for the success or failure of the landscape. The adequate design and functionality of an irrigation system is determinant to achieve the quality, economic and environmental targets of the landscape. This report starts with a historical outlook of the relevance of water in the landscape, from Antiquity to the present day, where there is a global crisis of water resources. This fact, along with the aesthetic and economic landscape concerns, is the main reason behind the great present interest on the application of Irrigation Management Plans to Landscape Architecture. In order to correctly manage a dynamical procedure such as irrigation, it is recognized that the best solution is to make use of a structured approach based on irrigation decision and efficiency programs. As a result, in this work an Irrigation Management Plan is considered as composed by four main stages, here described in detail: Planning, Scheduling, Monitoring and Evaluation. From this research we conclude in particular that an appropriate and continuously improved Irrigation Management Plan is the key for the successful achievement of any landscape project.
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Upendram, Sreedhar. "Irrigation scheduling, crop choices and impact of an irrigation technology upgrade on the Kansas High Plains Aquifer." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1423.
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Fontanet, i. Ambròs Mireia. "Optimal irrigation scheduling combining water content sensors and remote sensing data." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/668901.
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By 2025, the Food and Agriculture Organization of the United Nations predicts that two-thirds of the world population will experience water stress conditions. In addition, it is expected that world population will increase significantly during the following years. Agriculture is the largest consumer of fresh water, estimated 75%. The optimization of its use is therefore crucial for future. The main objective of irrigation scheduling is to guarantee maximum crop yield while saving significant amounts of water. The main difficulty to determine a correct and optimal irrigation scheduling strategy is due to complexity and variability of the Soil-Plant-Atmosphere continuum. In each field site, this continuous SPA has different patterns as a consequence of environmental conditions, crop, soil hydraulic properties and soil tillage. Several tools and methodologies are employed nowadays to monitor an improve irrigation scheduling. However, they all have advantages and limitations, or, each one is used without considering the information provided by the others, simplifying the system and avoiding information.
This thesis aims to improve irrigation scheduling by combining different tools available at the present time. This combination aims to answer different kind of questions when irrigation scheduling in a field site must be defined. For this, each tool has been used and supported by others. In addition, this thesis will discuss when and how these tools might be employed.
Firstly, we compare different tools and methodologies used to measure water content in an agriculture field. Specifically, we compared gravimetric measurements and water content sensors measurements with DISPATCH algorithm data. This algorithm is one of several algorithms who estimates soil surface water content using remote sensing data. The main goal was determining if remote sensing data can improve water content data measured by sensors. We found that DISPATCH algorithm is no capable to improve water content sensors measurements.
Secondly, we present a methodology where a simulation-optimization problem is solved in order to find an optimal irrigation scheduling strategy. This strategy might guarantee the maximum economic net margin. This methodology has been applied in a real field. The optimal irrigation scheduling of this field is compared with the traditional irrigation scheduling method, based water requirements. Results show that even though the traditional method supplies the volume of water evapotranspired, this methodology of scheduling irrigation is not enough to avoid crop water stress, compromising final crop yield. In this case, optimal irrigation strategy improves the final net margin in comparison the traditional method. We demonstrate that depending on soil properties, optimal irrigation scheduling is different.
Thirdly, we improved the irrigation scheduling in a field site where irrigation was applied with the same criteria. In this part of the thesis we employed NDVI remote sensing data, water content sensors and simulation models to determine the optimal irrigation. The improvement is based on management zones delineation with NDVI data. In this case, water content sensors are used to define if each management zone presents different water content patterns and to verify that when the field is divided into different management zones there is a gain in terms of water content uniformity. Finally, an optimal irrigation scheduling calendar is proposed to allow the consultants to take within-season irrigation decisions. Results show that management zones are dynamic during the growing season and the optimal irrigation scheduling might also be dynamic. In addition, we found that the uniform irrigation applied in the entire field, without considering the possible differences in soil properties, produced waterlogging in two management zones, therefore, transpiration decreases in comparison to the others.El 2025 la "Food and Agriculture Organization" de les Nacions Unides prediu que dues terceres parts de la població mundial patirà condicions d'estrés hídric. A més a més, s'espera que la població mundial augmenti els propers anys. L'agricultura és el consumidor principal d'aigua dolça, concretament un 75%. Considerant aquest context, existeix una necessitat important d'optimitzar l'aigua de reg en un futur proper. La programació del reg és l'encarregada de determinar el moment i la quantitat d'aigua que s'ha d'aplicar. El seu objectiu principal és garantir un rendiment màxim del cultiu i a la vegada estalviar aigua. La dificultat principal per determinar l'estratègia de programació de reg correcta i òptima és degut a la complexitat i variabilitat del continu Sòl-Planta-Atmòsfera. Diverses eines i metodologies són emprades avui en dia per monitoritzar i determinar la programació del reg. Malgrat l'àmplia variabilitat de possibilitats, totes elles tenen avantatges i limitacions, o sovint, cada una d'elles és fa servir sense considerar la informació que poden proporcionar les altres, simplificant el sistema i obviant informació. Aquesta tesis vol millorar la programació del reg combinant diferents eines i metodologies que estan disponibles avui en dia. La combinació té com a objectiu satisfer necessitats diferents en el moment que la programación del reg ha de ser definida, destacant les avantatges i minimitzant les limitacions de cada metodologia i eina, així com l'efecte de l'escala. Primerament, hem comparat diferents eines i metodologies per mesurar el contingut d'aigua al sòl en una parcel·la de cultiu. Concretament, s'han comparat mesures gravimètriques i de contingut d'aigua de sensors amb mesures de l'algorisme DISPATCH. Aquest algorisme és un de varis algorismes que estimen el contingut d¿aigua superficial del sòl emprant dades de teledetecció. L'objectiu principal era determinar si les dades de teledetecció poden millorar les dades de contingut d'aigua mesurades pels sensors. El resultats mostren que, ara per ara i considerant les condicions de camp, el DISPATCH no és capaç de millorar les mesures dels sensors de contingut d'aigua al sòl. Després, presentem una metodologia on es soluciona un problema de simulació-optimització per a determinar una estratègia de programació de reg òptim. Aquesta estratègia ha de garantir un rendiment econòmic net màxim. S'ha aplicat en una parcel·la de cultiu real. L'estratègia de programació de reg òptim ha estat comparat amb el mètode tradicional de programació de reg, que està basat amb el càlcul de les necessitats hídriques. Encara que el mètode tradicional reemplaça per complet l'aigua evapotranspirada, els resultats mostren que la manera de repartir l'aigua no evita l'estres hídric del cultiu, disminuint el rendiment. En aquest cas, la programació del reg òptim millora el rendiment econòmic net. Els resultats mostren que depenent el tipus de sol, la programació del reg ha de ser diferent. Finalment, s'ha millorat la programació del reg en una parcel·la de cultiu on el reg s'havia aplicat uniformement en tota la seva extensió. En aquesta part de la tesis, es fan servir dades de teledetecció de NDVI, dades de sensors de contingut d'aigua al sòl i models de simulació per a determinar el reg òptim. La millora està basada en la delineació de zones maneig amb les dades de NDVI. En aquest cas, els sensors s'han emprat per a determinar si casa zona de maneig representa diferents patrons de contingut d'aigua i per a validar si quan la parcel·la és dividida en zones de maneig, la variabilitat disminueix. Finalment, es proposa un calendari de programació de reg òptim per a poder prendre decisions en la campanya de reg. Els resultat mostren que les zones de maneig són dinàmiques així com el reg òptim. A més a més s'ha vist que el reg uniforme produeix asfixia radicular a dues de les zones de maneig, disminueix la transpiració en comparació amb els altres.
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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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Ramadan, Mahmoud Hany Abd El-Aziz. "Modelling for irrigation scheduling with particular reference to the potato crop." Thesis, Imperial College London, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300101.
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Teowolde, Haile, Robert L. Voigt, Mahamoud Osman, and Albert K. Dobrenz. "Water Stress Indices for Research and Irrigation Scheduling in Pearl Millet." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/204250.
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The capability to measure the magnitude of water stress in plants is useful for precision irrigation scheduling and other purposes. This paper reports an evaluation of leaf (TL) and canopy (Tc) temperatures, leaf minus air (TL -Ta) and canopy minus air (Tc -Ta) temperatures, and leaf water stress index (LWSI) and crop water stress index (CWSI) in detecting stress in pearl millet (Pennisetum americanum (L.) Leeke) over two growing seasons. Baselines which were used to compute LWSI and CWSI were obtained. The upper and lower baselines for the Tc data, respectively, were Tc -Ta = 4.10 C and Tc -Ta = 3.87- .2001VPD where VPD is vapor pressure deficit in mbars. For the TL data, the upper and lower baselines, respectively, were TL -Ta = 1.97oC and TL -Ta = 1.308- .03006VPD. Tests against photosynthesis, transpiration, and grain yield showed that LWSI and CWSI are better indices of stress than TL -Ta, Tc -Ta, TL, Tc, or Ta. Average seasonal LWSI and CWSI ranged from approximately 0.03 for non- stressed to 0.80 for stressed plants. The reliability of LWSI and CWSI to detect stress and their relation with grain yield suggested the possibility of using these indices for irrigation scheduling decisions.
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Garrot, D. J. Jr, D. D. Fangmeier, S. H. Husman, and S. Stedman. "On Farm Cotton Irrigation Scheduling Management Using Infrared Thermometers in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204859.
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Yildirim, Saadettin. "Use of tensiometers for computer-control of irrigation for container-grown plants." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1300990866.
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Kisekka, Isaya. "Evapotranspiration based irrigation scheduling for a tropical fruit orchard in south Florida." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025090.
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Clark, L. J., E. W. Carpenter, T. Scherer, D. Slack, and F. Fox. "Irrigation Scheduling on Long and Short Staple Cotton, Safford Agricultural Center, 1989." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208306.
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Two irrigation scheduling trials were performed in 1989, one for short staple and one for long staple. Yields in the trials were very good with the best treatments yielding over 1700 and 1600 pounds of lint per acre for DP 90 and S-4 respectively. The treatment using Infrared thermometry was the best overall treatment in the short - staple trial, with the highest yield, the highest percent first pick, the shortest plants, the lowest water use and the highest water use efficiency. The two computer methods were very close to the IR treatment in yield and percent first pick, but grew taller plants with more water and were not as efficient with their water use. The trial on long staple cotton was encouraging in that reasonable yields were obtained using short-staple parameters. The computer model using AZMET data yielded significantly lower than the other treatments, indicating that we need to refine the evapotranspiration crop coefficients.
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Clark, L. J., E. W. Carpenter, T. F. Scherer, D. C. Slack, and F. Jr Fox. "Irrigation Scheduling on Long and Short Staple Cotton Safford Agricultural Center, 1990." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208345.
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Three irrigation scheduling techniques are compared on both long and short staple cotton in replicated small plot trials on the Safford Agricultural Center. The Erie method uses historical evapotranspiration data developed in the Mesa area but mathematically adjusted for the elevation in Safford and incorporated in a computer spreadsheet. The AZSCHED method is a near real -time irrigation scheduling program using AZMET weather date, a modified Penman equation and heat unit based crop coefficients to calculate water deficits. This program will schedule irrigations on up to 60 fields. The third method utilizes infrared thermometry to determine crop water stress indices from foliage temperatures, ambient temperature and relative humidity. This latter method was used to track the crop stress throughout the growing season on all treatments. All three methods were considered successful for both long and short staple cotton with the Erie method yielding higher than the other two for both types of cotton. Further refinements will be made on the AZSCHED method until it performs at or above the Erie method
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Conaty, Warren Charles. "TEMPERATURE-TIME THRESHOLDS FOR IRRIGATION SCHEDULING IN DRIP AND DEFICIT FURROW IRRIGATED COTTON." Thesis, The University of Sydney, 2011. http://hdl.handle.net/2123/7709.
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Water is one of the most limiting factors to Australian cotton production. Improved irrigation scheduling efficient water use is central to the sustainability of the Australian irrigated cotton industry. Irrigation scheduling is a two-fold process where-by the amount and frequency of water applied to a plant is determined. Producers must aim to optimise crop water use through timely irrigation scheduling and efficient utilisation of in-crop rainfall. Currently, furrow irrigation is the dominant form of irrigation delivery and cotton farmers use a limited range of methods to make irrigation decisions. A combination of the cost, accuracy and complexity of these methods has limited their effective use in commercial production. In this study a potentially simpler method based on crop canopy temperatures and the thermal optimum concept was investigated. Compared to well-watered plants, water stressed plants exhibit elevated canopy temperatures. This is a consequence of the closing of stomata, in response to soil water deficits. The closure of stomata results in a decrease in transpiration and consequently a reduction in latent energy flux, leading to a rise in canopy temperatures. However, ambient conditions can have a large influence on canopy temperatures; thus canopy temperatures are a reflection of both plant and environmental factors. In order to develop indicators of the early onset of water and temperature stress, research conducted in the USA developed a theory that defined optimal plant temperatures with respect to the thermal dependence of the Michaelis-Menten constant of an enzyme (Km). The optimal enzymatic function was restricted to a range of ambient temperatures that was termed the thermal kinetic window (TKW), which is an indicator of the optimal temperature range of a plant species. Using alternative diagnostic methodologies of chlorophyll fluorescence recovery rates and analysis of plant physiological function under field conditions, the optimal temperature of an Australian cultivar was identified to be ~28 °C. Although this was consistent with values obtained from US cotton cultivars, and average day-time canopy temperatures that were achieved in the field at close to optimal water applications, it was important to verify this as Australian cotton cultivars are genetically different to US cultivars and the combined effect of different genetics and ecological adaptations may potentially influence the optimal temperature of biochemistry. The TKW theory was used as the basis for the BIOTIC (Biologically Identified Optimal Temperature Interactive Console) protocol. This protocol was developed by researchers at the USDA-ARS, and uses the relationship between canopy temperature (Tc) and plant water status to schedule irrigation using a temperature-time threshold system. Irrigations are commanded when the crop’s Tc exceeds an optimal temperature threshold for a pre-determined period of time. Using the BIOTIC system as a basis, this study aims to assess the physiological base and utility of the thermal optimal approach to schedule irrigation, with particular emphasis on its use in precision application and large soil water deficit irrigation systems of the Australian cotton industry. Deficit irrigation is an optimisation strategy where full crop water requirements are not necessarily provided, improving water-use efficiency (WUE). The thermal optimal approach was studied previously; however, its use was limited to irrigation systems that provide full water requirements at high irrigation frequencies and low irrigation volumes. Hence, its application to deficit and furrow irrigation systems was unknown. The physiological basis of the principles underlying the thermal optimum concept for irrigation scheduling was examined through the monitoring of Tc of the commercial cotton cultivar Sicot 70BRF at ‘Myall Vale’ Narrabri Australia. Surface drip irrigation experiments were conducted in the 2007/08 and 2008/09 seasons, where irrigation treatments were based on daily crop evapotranspiration (ETC) rates calculated using the FAO56 protocol with a locally calibrated crop coefficient. A furrow-irrigated experiment was conducted in the 2008/09 season, where irrigation treatments were based on plant available soil water deficits (mm) from field capacity calculated from neutron attenuation data. The objectives of this research were to: (1) confirm that the optimum temperature (Topt) of a current commercial Australian cotton cultivar (Sicot 70BRF) is the same as other measured USA cotton cultivars; (2) determine if Tc can define plant water stress by comparison with soil and atmospheric conditions; and (3) determine the potential of the thermal optimum approach to scheduling irrigation in Australian cotton systems. The hypothesis that Tc provides sufficient information for irrigation scheduling was investigated in the surface drip and furrow irrigated cotton. Irrigation treatments resulted in differences in lint yield, plant architecture, growth, biomass accumulation and Tc. Canopy temperatures were correlated with crop lint yield and the volume of water applied to the crop. Peak lint yields occurred at average day-time (Rn > 300 W m-2) Tc of 26.4 ± 1.7 °C and total water of 108% calculated ETC under surface drip conditions, and at Tc of 28.6 °C ± 0.6 °C and water supplies of 99% calculated ETC under furrow irrigated conditions. Acclimation of Tc due to the wetting and drying cycles of furrow irrigation did not occur and the combination of both furrow and drip irrigated data showed a single relationship where peak lint yields occurred at Tc of 28 °C. This highlights the benefits of maintaining average canopy temperatures close to 28 °C, and supports the potential utility of the thermal optimum concept in Australian drip and furrow irrigated cotton. Although lint yield is proportional to the thermal optimum, the physiological limitations of a plant can mean that a well-watered plant’s Tc can still exceed the thermal optimum. This gives rise to the stress time (ST) concept, where ST represents the average daily period of time that a well-watered crop’s Tc can exceed its optimum temperature. The ST concept was tested and adapted to Australian field-based drip and furrow irrigation systems. Peak lint yields and crop WUE (the ratio of lint yield produced per hectare to the cumulative amount of water used by the crop through evapotranspiration) in drip-irrigated cotton occurred at 4.5 h ST, considerably higher than the empirically calculated threshold of 2.8 h. A thermal optimum protocol was developed to schedule furrow irrigation events through a cumulative ST approach, where one ST h represents 0.6 mm plant available soil water depletion, enabling a producer to determine the desired soil water deficit and schedule irrigations based on cumulative ST. An integrated approach to stress detection was also proposed. This approach, the sum of cumulative ST, is theoretically advantageous as it considers both the degree and duration of time Tc exceeding the optimum. The physiological principle underlying a thermal optimal approach to irrigation scheduling were analysed in this thesis. An independently estimated optimal temperature was determined to be 28 °C. This optimal temperature was correlated with peak lint yields, and Tc was responsive to irrigation. A stress time threshold producing peak lint yield was developed in surface drip irrigation systems, and a cumulative stress time threshold for soil water deficits was outlined for furrow irrigation systems. These modified stress time thresholds provided the information required to detect water stress for irrigation scheduling. The practical implication of this research is that temperature-time thresholds in a thermal optimal irrigation scheduling system have utility in the irrigated Australian cotton industry. However, the time thresholds that were determined in this study were developed by monitoring cotton crops with infra red thermometers, and irrigations were not scheduled with a thermal optimum protocol in this study. With field validation, these irrigation protocols could be used as the basis for a modified BIOTIC system and be adopted by the commercial cotton industry, as it is a simple, cost effective irrigation scheduling system.
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Garrot, Donald J. Jr, Delmar D. Fangmeier, and Stephen H. Husman. "Scheduling Irrigations on Cotton Based on the Crop Water Stress Index." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/204489.
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The Crop Water Stress Index (CWSI) was used to schedule irrigations on drip irrigated cotton research plots in Tucson and on eight acre furrow irrigated fields at the Marana and Maricopa Agricultural Centers. Scheduling irrigations when plots reached 0.30 CWSI units resulted in highest yields with 1403 lbs/acre cotton lint using 33.8 inches of water. The Marana and Maricopa fields yielded 1322 lb/acre on 28 inches and 1767 lb/acre on 58 inches of water, respectively.
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Nikfal, Mohammadreza. "Developing a Soil Moisture-Based Irrigation Scheduling Tool (SMIST) Using Web-GIS Technology." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157621/.
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Software as a service (SaaS) is a primary working pattern and a significant application model for next generation Internet application. Web GIS services are the new generation of the Software as a service that can provide the hosted spatial data and GIS functionalities to the practical customized applications. This study focused on developing a webGIS based application, Soil Moisture-Based Irrigation Scheduling Tool (SMIST), for predicting soil moisture in the next seven days using the soil moisture diagnostic equation (SMDE) and the upcoming seven precipitation forecasts made by the National Weather Service (NWS), and ultimately producing an accurate irrigation schedule based on the predicted soil moisture. The SMIST is expected to be capable of improving the irrigation efficiency to protect groundwater resources in the Texas High Plains and reducing the cost of energy for pumping groundwater for irrigation, as an essential public concern in this area. The SMIST comprised an integration of web-based programs, a Hydrometeorological model, GIS, and geodatabase. It integrates two main web systems, the soil moisture estimating web application for irrigation scheduling based on the soil moisture diagnostic equation (SMDE), and an agricultural field delineation webGIS application to prepare input data and the model parameters. The SMIST takes advantage of the latest historical and forecasted precipitation data to predict soil moisture in the user-specified agricultural field(s). In this regard, the next seven days soil moisture versus the soil moisture threshold for normal growth would be presented in the result page of the SMIST to help users to adjust irrigation rate and sequence.
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Clark, Lee J., and Keller F. Ellsworth. "Irrigation scheduling on small grains using AZSCHED for Windows - Safford Agricultural Center, 2004." College of Agriculture, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/203871.
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The AZSCHED irrigation scheduling software was developed in the early 1990's to be used in a DOS environment on computers (1) and has been used extensively for irrigation scheduling on the Safford Agricultural Center since its development. The new Windows version of AZSCHED (2) was first tested for barley and wheat in 2003. This is a follow-up verification to the first test using a wider range of irrigation depletion levels.
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Clark, Lee J., and Keller F. Ellsworth. "Irrigation scheduling on small grains using AZSCHED for Windows - Safford Agricultural Center, 2003." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/205403.
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The AZSCHED irrigation scheduling software was developed in the early 1990's to be used in a DOS environment on computers (1). Since it’s development it has been extensively used for irrigation scheduling on the Safford Agricultural Center. Changes in computer systems from DOS to Windows has made it imperative that a new Windows version of AZSCHED be developed. That version has been developed and is now in use at our location (2). This report covers the use of this software in scheduling irrigation for barley and wheat.
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Clark, L. J., and E. W. Carpenter. "Irrigation Scheduling on Barley and Durum Wheat at the Safford Agricultural Center, 1998." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/208277.
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A study was done on durum wheat and barley to determine the economical consequences of irrigation scheduling. Delays of 3 days and 7 days were applied after AZSCHED software called for irrigations to similate a wait for water from the irrigation canal. Yields were reduced by the delays, but with the crop values reduced by the cost of irrigation no money was lost in delaying irrigations on the durum wheat and $8-9 per acre was lost on the barley.
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Garrot, D. J. Jr, S. Stedman, D. D. Fangmeier, S. H. Husman, and B. Benedict. "Pima Cotton Irrigation Scheduling Using Infrared Thermometers and the Crop Water Stress Index." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208265.
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The Crop Water Stress Index (CWSI) was used to schedule irrigations on Pima S-6 cotton on 12 four-acre furrow-irrigated test plots in Coolidge and 20 drip- irrigated test plots at the Campus Agricultural Center in Tucson. Scheduling irrigations between 0.30 and 0.50 CWSI units resulted in highest lint production and plant water use efficiency at both locations.
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Husman, Stephen H., Donald J. Jr Garrot, Delmar D. Fangmeier, and Norman F. Oebker. "Sweet Corn Irrigation Scheduling Using Infrared Thermometers and the Crop Water Stress Index." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/214474.
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The Crop Water Stress Index (CWSI) was used to schedule irrigations on Jubilee sweet corn on 12 drip- irrigated plots at the Campus Agricultural Center in Tucson. Irrigations were to be scheduled at 0.15, 0.35, and 0.50 CWSI values to represent a wet, medium and a dry treatment. Actual average CWSI values at time of irrigation were for 0.14, 0.36, and 0.48. There were no significant yield or quality differences for the wet and medium treatments with exception of a greater ear diameter in the wet treatment. Yield and quality significantly decreased for the dry treatment scheduled at a CWSI value of 0.48. Irrigation application totals were 26.4, 24.2 and 18.3 inches for the wet, medium and dry treatments respectively.
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Zeywar, Nadim Shukry. "Water use and crop coefficient determination for irrigated cotton in Arizona." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185887.
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Crop coefficients (K(c)) are a useful means of predicting how much water is needed for irrigating a crop. The crop water stress index (CWSI), on the other hand, is a means of knowing when to irrigate. Two field experiments were conducted during the summers of 1990 and 1991 at Maricopa Agricultural Center and Marana Agricultural Center, respectively, to evaluate water use (evapotranspiration, ET) of different cotton varieties, to develop crop coefficients for cotton grown in the state of Arizona, and to evaluate empirical and theoretical crop water stress indices under field conditions. For the 1990 experiment, ET from the cotton variety DPL 77 was obtained using soil water balance (SWB) and steady state heat balance (SSHB) techniques. For the 1991 experiment, ET from two cotton varieties (DPL 20 and Pima S-6) was estimated using the Bowen ratio energy balance (BREB) method and the steady state heat balance method. Reference evapotranspiration (ETᵣ) was obtained from weather stations located close to the experimental plots. Average daily ET from the SSHB measurements ranged from 8.24 to 15.13 mm and from 10.34 to 12.12 mm for the 1990 and 1991 experiments, respectively. Total ET from the SWB was approximately 19% less than the total ET estimated by the SSHB. Total ET from individual plants was well correlated with average stem area over the evaluation periods. Daily ET from the two cotton varieties (DPL20 and Pima S-6) was approximately similar when irrigation conditions were the same, but differed later by as much as 48.4% as irrigation continued for the variety Pima S-6 only. Daily ET from the BREB measurements and ETᵣ were used to develop a crop coefficient curve for cotton grown at Marana, Arizona, which had a maximum smoothed value of 1.21. A critical value of CWSI equal to 0.3 was obtained by observing the pattern of the CWSI values over well-watered and drier conditions, and from previous research. Using the developed crop coefficient curve and the CWSI should provide a useful means of scheduling irrigation for cotton grown under climatic conditions similar to those at Marana, Arizona.
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Van, der Westhuizen Rykie Jacoba. "Irrigation scheduling of tomatoes (Lycopersicon esculentum Mill.) and cucumbers (Cucumis sativus L.) grown hydroponically in coir." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1086.
Full textAbstract:
Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: The use of capacitance water sensors for the scheduling of irrigation for hydroponic tomato and cucumber crops grown in coir was investigated in a series of laboratory and glasshouse experiments in the Free State province of South Africa. Laboratory experiments in a climate controlled chamber were conducted to accurately calibrate ECH2O capacitance sensors, models EC-10 and EC-20, in coir with an improved calibration procedure. Water content predictions by the coir-specific calibration and manufacturer’s calibration equations were compared to actual water content measured from mass loss of the coir sample. The manufacturer’s calibration equation indicated a poor accuracy of prediction, which mostly underestimated the volumetric water content, compared to the near perfect prediction of the coir-specific calibration of individual sensors. A rapid calibration procedure for EC-10 and EC-20 sensors was proposed to reduce the calibration time of the sensors and promote their commercial use for irrigation management in coir. The accuracy of prediction by the rapid calibration procedure for the plant available water content range was high for both EC-10 and EC-20 sensors and allowed for the compensation for variation between sensors. Glasshouse studies aimed to characterise the water retention and ability of coir to supply water to greenhouse tomato and cucumber crops through the continuous monitoring of medium water content in small and large growing bags with the EC-10 and EC-20 capacitance sensors during a drying cycle, compared to well-watered plants. Stages of crop water stress were identified and, based only on the plant’s response to the drying cycle, it was suggested that water depletion can be allowed to the point of mild water stress for both greenhouse tomato and cucumber crops, which can be detected by soil water sensors. In a second series of glasshouse experiments, the identified stages of crop water stress were used to determine and apply depletion levels in coir and compare this irrigation strategy to a well-watered treatment for greenhouse cucumber and tomato plants, with regard to the water balance components, yield and water use efficiency for different bag sizes. Results indicated that irrigation was successfully managed to the pre-determined water depletion levels for cucumber and tomato plants in coir, through the use of in situ calibrated capacitance sensors. For both crops the depletion of water varied between bag sizes, indicating that various bag sizes require different irrigation management strategies. Scheduling to the highest pre-determined by 124 L m-2 in the small and 240 L m-2 in the large bags for cucumbers and 427 L m-2 in the small and 487 L m-2 in the large bags for tomato plants, compared to the well-watered treatments. Yields achieved by the greenhouse tomato plants in the large growing bags and cucumber plants in the small and large bags were maintained or improved when scheduled to the highest depletion level (approximately 60% available water content) compared to the well-watered treatment. The combination of reduced irrigation and improved or maintained yields resulted in improved water use efficiencies (based on irrigation and transpiration) for the highest depletion level compared to the well-watered treatments. In all glasshouse experiments the well-watered treatment resulted in luxury water use by the plants. Finally, a study was conducted in order to compare crop water stress of greenhouse cucumber and tomato plants under luxury water supply and cyclic water deficit conditions. The comparison was based on the transpiration ratio and yield, while the use of capacitance sensors was evaluated for irrigation scheduling in coir for both crops. Transpiration data indicated that cucumber and tomato plants subjected to luxury water supply experience water stress earlier than plants subjected to cyclic water deficit conditions, irrespective of bag size. Results also indicated that irrigation scheduling according to water depletion levels in small bags is not yet recommended for greenhouse tomato and cucumber plants grown in coir, until further research is conducted. Scheduling to water depletion levels in large bags is, however, justified by the improved or maintained yields of the greenhouse cucumber and tomato plants. The estimated depletion levels for large bags beyond which yield are reduced was at 85% for tomatoes and 70% for cucumbers. In conclusion, the results clearly indicated that the use of capacitance sensors in large growing bags improves irrigation management of hydroponic cucumbers and tomatoes in coir by eliminating over-irrigation and improving water use efficiency. More research is needed before a conclusion can be made regarding irrigation scheduling with capacitance sensors in small growing bags.
AFRIKAANSE OPSOMMING: Die gebruik van kapasitansie water sensors vir besproeiingskedulering van tamatie en komkommer plante wat hidroponies in kokosveen gegroei is, is ondersoek in ‘n reeks laboratorium en glashuis eksperimente in die Vrystaat provinsie van Suid Afrika. Laboratorium eksperimente is uitgevoer in ‘n klimaat beheerde kas om ECH2O kapasitansie sensors, modelle EC-10 en EC-20, akkuraat te kalibreer vir kokosveen deur ’n verbeterde kalibrasie prosedure. Waterinhoud voorspellings deur die kokosveen spesifieke kalibrasie en die vervaardiger se kalibrasie vergelykings is vergelyk met die werklike waterinhoud wat gemeet is deur die kokosveen monster se massaverlies te monitor. Akkuraatheid van voorspelling deur die vervaardiger se kalibrasie vergelykings was swak en het meestal die volumetriese waterinhoud onderskat in vergelyking met die byna perfekte voorspelling deur die kokosveen spesifieke kalibrasie van individuele sensors. ’n Vinnige kalibrasie prosedure vir die EC-10 en EC-20 sensors is voorgestel om die kalibrasie tyd te verkort en die kommersiële gebruik van die sensors vir besproeiingsbestuur in kokosveen aan te moedig. Die akkuraatheid van voorspelling deur die vinnige kalibrasie prosedure, binne die grense van plant beskikbare waterinhoud, was hoog vir beide EC-10 en EC-20 sensors, terwyl die prosedure ook voorsiening maak vir variasie tussen sensors. Glashuis studies is uitgevoer om die water retensie en vermoë van kokosveen om water te voorsien aan tamatie en komkommer gewasse in kweekhuise, te karakteriseer. Dit is bereik deur die mediumwaterinhoud van klein en groot plantsakke deurlopend te monitor met behulp van die EC-10 en EC-20 kapasitansie sensors gedurende ’n uitdroging siklus, en dit te vergelyk met ’n waterryke behandeling vir elke gewas waarvolgens die plante agt keer per dag besproei is. Fases van gewas waterstremming is geïdentifiseer en, volgens die reaksie van die plant tot die drogingsiklus, is dit voorgestel dat wateronttrekking toegelaat kan word tot die punt van matige waterstremming wat aangewys kan word deur kapasitansie water sensors vir beide kweekhuis tamatie en komkommer gewasse. In ’n tweede reeks glashuis eksperimente is die geïdentifiseerde fases van gewas waterstremming gebruik om onttrekkingsvlakke vir kokosveen te bepaal en toe te pas as besproeiingskeduleringstrategie vir kweekhuis komkommer en tamatie plante. Toegepaste vlakke is vir elke gewas vergelyk met ’n waterryke behandeling ten opsigte van die waterbalans komponente, opbrengs en watergebruiksdoeltreffendheid in verskillede sakgroottes. Resultate het aangedui dat besproeiing suksesvol bestuur is tot die voorafbepaalde wateronttrekkingsvlakke vir komkommer entamatie plante in kokosveen, deur gebruik te maak van in situ gekalibreerde kapasitansie sensors. Die onttrekking van water deur beide gewasse het verskil tussen klein en groot sakke, wat aangedui het dat verskillende sakgroottes verskillende besproeiingsbestuur strategieë vereis. Skedulering tot die hoogste voorafbepaalde onttrekkingsvlak het, in vergelyking met die waterryke behandelings, besproeiing verminder met 124 L m-2 in die klein en 240 L m-2 in die groot sakke vir komkommers, en 427 L m-2 in die klein en 487 L m-2 in die groot sakke vir tamatie plante. Opbrengste van kweekhuis tamatie plante in die groot plantsakke en komkommer plante in die klein en groot sakke is gehandhaaf of verbeter deur skedulering tot die hoogste onttrekkingsvlak (ongeveer 60% van beskikbare water inhoud), in vergelyking met die waterryke behandeling. Die kombinasie van verminderde besproeiing en verbeterde of gehandhaafde opbrengste het gelei tot verbeterde watergebruiksdoeltreffendheid (besproeiing en transpirasie) vir die hoogste onttrekkingsvlak, in vergelyking met die waterryke behandelings. In al die glashuis eksperimente het die waterryke behandeling gelei tot oorvloedige watergebruik deur plante. ’n Finale studie is uitgevoer om gewas waterstremming van kweekhuis komkommer en tamatie plante wat onderwerp is aan oorvloedige watervoorsiening deur agt keer per dag te besproei en sikliese watertekorttoestande, te vergelyk. Die vergelyking is gebaseer op die transpirasie verhouding en opbrengs, terwyl die gebruik van kapasitansie sensors vir besproeiingskedulering in kokosveen vir beide gewasse geëvalueer is. Transpirasie data het aangedui dat komkommer en tamatie plante wat onderwerp is aan oorvloedige watervoorsiening vroeër waterstremming ervaar as plante wat onderwerp is aan sikliese watertekorttoestande, ongeag van die sakgrootte. Resultate het aangedui dat besproeiingskedulering volgens wateronttrekkingsvlakke vir klein sakke nog nie aanbeveel kan word vir kweekhuis tamatie en komkommer plante alvorens verdere navorsing gedoen is nie. Skedulering tot wateronttrekkingsvlakke vir groot sakke word egter geregverdig deur die verbeterde of gehandhaafde opbrengste van kweekhuis komkommers en tamaties. Die beraamde laagste onttrekkingsvlakke vir groot sakke wat nie opbrengs betekenisvol sal beïnvloed nie is 85% vir tamaties en 70% vir komkommers. Ten slotte dui die resultate duidelik daarop dat die gebruik van kapasitansie sensors in groot plantsakke besproeiingsbestuur van hidroponiese komkommers en tamaties in kokosveen verbeter deur oorbesproeiing uit te skakel en die watergebruiksdoeltreffendheid te verbeter. Meer navorsing is nodig alvorens ’n gevolgtrekking gemaak kan word ten opsigte van besproeiingskedulering met kapasitansie sensors in klein plantsakke.