Estimating Crop Yield And Production Changes As A Function Of Irrigation Deficit Based On Watershed And County Level Data
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Estimating Crop Yield And Production Changes As A Function Of Irrigation Deficit Based On Watershed And County Level Data
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Author : Priscila Darakjian
language : en
Publisher:
Release Date : 2000
Estimating Crop Yield And Production Changes As A Function Of Irrigation Deficit Based On Watershed And County Level Data written by Priscila Darakjian and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Crops and water categories.
Response of agricultural crops to irrigation water deficit is well-understood at the field scale. Broader scale (watershed and county levels) studies have been less frequently performed. Data collection at the field level for extensive areas is time consuming and expensive. The importance of studies at a broader scale for evaluating future scenarios of agricultural land use justifies exploring alternative approaches that produce reasonable results in a faster and more economical manner. The objective of this study was to verify the ability of coarser level data to provide general trends of changes in agricultural cropping patterns as a function of water use management in the Willamette basin. In this study, watershed and county level data were used to analyze broader scale crop water relationships, since these data are abundant and easily accessible. Further, future estimates of crop water use, based on estimates of yield and acreage changes, were attempted for a study period spanning current conditions (2000) through 2050. FAO Yield Response to Water Model was used to relate crop yield and production to applied irrigation water. Assumptions made to apply this model at the basin level related mostly to climatic factors and dynamic change of the system. Changes in maximum crop yield for all important crops grown in the Willamette basin were estimated using a logistic function parameterized with historic and current datasets. It was important to consider the dynamic system response when modeling the system to incorporate environmental, technological and socio-economic factors not reflected in the original model. The results for crop yield showed a decrease through time for sweet corn, stable yield for cherries, ryegrass, and grapes, and increasing yield for alfalfa, strawberries and raspberries. Crops showing higher sensitivity to water deficit included snap beans, winter and spring wheat, oats and filberts. Production estimates showed 3 groups of crops: predominantly successful (filberts, cherries, ryegrass, oats and spring wheat), stable (strawberries, alfalfa, orchardgrass, mint and fescue) and predominantly unsuccessful crops (winter wheat, sweet corn, snap beans and berries). County level and watershed level data proved helpful in developing a more comprehensive view of crop production and its irrigation deficit response, using models incorporating information from finer spatial scale experiments. Socio-economic, technologic and environmental variables that might influence agriculture over time should be investigated in further studies.
Deficit Irrigation Practices
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Author : Food and Agriculture Organization of the United Nations
language : en
Publisher: Food & Agriculture Org.
Release Date : 2002
Deficit Irrigation Practices written by Food and Agriculture Organization of the United Nations and has been published by Food & Agriculture Org. this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Technology & Engineering categories.
In the context of improving water productivity, there is a growing interest in deficit irrigation, an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. Under conditions of scarce water supply and drought, deficit irrigation can lead to greater economic gains than maximizing yields per unit of water for a given crop; farmers are more inclined to use water more efficiently, and more water-efficient cash crop selection helps optimize returns. However, this approach requires precise knowledge of crop response to water as drought tolerance varies considerably by species, cultivar and stage of growth. The studies present the latest research concepts and involve various practices for deficit irrigation. Both annual and perennial crops were exposed to different levels of water stress, either during a particular growth phase, throughout the whole growing season or in a combination of growth stages. The overall finding, based on the synthesis of the different contributions, is that deficit or regulated-deficit irrigation can be beneficial where appropriately applied. Substantial savings of water can be achieved with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behavior is required, as crop response to water stress varies considerably.
New Data For Representing Irrigated Agriculture In Economy Wide Models
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Author :
language : en
Publisher:
Release Date : 2017
New Data For Representing Irrigated Agriculture In Economy Wide Models written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
We develop a framework to represent the value of irrigated crop production and the expansion potential of irrigated land within economy-wide models, providing integrated assessment capabilities for energy, land, and water interactions. Specifically, we compute the value of production on irrigated and rainfed cropland at both a 5 arcminute by 5 arcminute level (about 10 square kilometers) and for the 140 regions and eight crop sectors in Version 9 of the Global Trade Analysis Project (GTAP) Data Base. For each crop category, we estimate the shares of production on irrigated and rainfed land using estimates of production quantities and prices, compared to approximations based on output volumes used in the GTAP-Water Data Base. We construct a global dataset of evaluation metrics to identify region-crop combinations where there are large differences in irrigated production value shares based on direct calculation and approximated by output volumes. The scope to expand the amount of irrigated land and the cost of doing so is quantified through irrigable land supply curves for 126 water regions globally, based on water availability and the costs of irrigation infrastructure. We also make available our adaptable work stream to calculate crop production values and to estimate irrigable land supply elasticities for use in economy-wide models. Altogether, this work can enhance integrated assessment and economy-wide modeling by more accurately capturing the value of crop production and facilitating the representation of endogenous investment in irrigation infrastructure in response to changing water availability. These data and modeling contributions allow for a more rigorous exploration of the regional and global impacts of water availability on land use, energy production, and economic activity
Optimization Of Water Use Efficiency In Crop Production Systems By Dynamic Simulation Of Crop Behavior Under Stochastic Regimes
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Author : Jamil Ahmed
language : en
Publisher:
Release Date : 1974
Optimization Of Water Use Efficiency In Crop Production Systems By Dynamic Simulation Of Crop Behavior Under Stochastic Regimes written by Jamil Ahmed and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1974 with categories.
Effects Of Irrigation Frequency On Yields Of Winter Wheat
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Author : Brian Clifford Nakamura
language : en
Publisher:
Release Date : 1982
Effects Of Irrigation Frequency On Yields Of Winter Wheat written by Brian Clifford Nakamura and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Irrigation efficiency categories.
Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits affect yields and the interaction of the deficits with the scheduling of irrigations. A field experiment was conducted during the 1981 irrigation season to investigate the effects of high and low frequency deficit irrigation on yields of winter wheat. Yield and water use data were used to construct three production functions. The relationship between the level of water use and the resulting yield were determined for three irrigation frequency regimes. Field plots under daily (high frequency), weekly (normal frequency), and stress (reduced frequency) regimes were included in the field experiment as well as two dryland production plots. The relationships derived from this project were characterized by a large degree of scatter in the results. Highly favorable weather conditions offset the effects of irrigation deficits on plant yields throughout the irrigation season. At this time, a second year of data is in the process of compilation. The results of a regression analysis showed no statistically significant difference in the water use-yield relationships of the three irrigation frequency regimes. The effect of frequency did not lead to any readily apparent differences in the three production functions. The efficiency of water use of the different irrigation frequencies increases with decreasing amount of applied water for the 1981 crop year. The most efficient treatment, i.e., least water use per unit of yield, was the pre-plant irrigated, dryfarmed plots. The density of the wheat, a measure of crop quality also increased with decreased water use in this experiment. The optimal irrigation treatment (measured by production and quality) was the two-week frequency set.
Potential Effects Of Irrigation Practices On Crop Yields In Grand Valley
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Author : Gaylord V. Skogerboe
language : en
Publisher:
Release Date : 1979
Potential Effects Of Irrigation Practices On Crop Yields In Grand Valley written by Gaylord V. Skogerboe and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1979 with Corn categories.
Water Resources And Irrigation Development In Ethiopia
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Author : Seleshi Bekele Awulachew
language : en
Publisher: IWMI
Release Date : 2007
Water Resources And Irrigation Development In Ethiopia written by Seleshi Bekele Awulachew and has been published by IWMI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Irrigation categories.
Irrigation programs / Water use / Reservoirs / Lakes / River basins / Water potential / Water resources
Risk Return Analysis Of Irrigation System Design And Operating Rules
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Author : Kim C. Nielsen
language : en
Publisher:
Release Date : 1982
Risk Return Analysis Of Irrigation System Design And Operating Rules written by Kim C. Nielsen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Irrigation efficiency categories.
A model was developed to simulate winter wheat production on irrigated farmland similar to that found near Hermiston, Oregon. The simulated farm is irrigated with a side roll sprinkler system. A well is located adjacent to the wheat field and the water is delivered by an electrically powered pump. The major components of the model are: 1. The soil moisture component which estimates daily soil moisture level. The soil moisture level is a function of daily precipitation, daily irrigation and daily evapotranspiration. Evapotranspiration is calculated as a function of measured pan evaporation, wheat plant stage of development and the soil moisture level. 2. The irrigation component which schedules daily irrigation based on the decision strategies supplied by the model user. There are three major parts of each strategy, the irrigation system design, the set time in hours and the soil moisture level that initiates irrigation. 3. The yield component of the model which estimates wheat grain yield as a function of daily temperature, daily soil moisture, and stage of plant growth. The scheduling of irrigation will create variability in the soil moisture level across the field. This variability of soil moisture is incorporated in the yield component. 4. The risk/returns component which calculates the net returns and utility. Utility is equal to the average net return minus the standard deviation weighted by a risk aversion factor. Wheat production was simulated for 19 years of daily weather data from the Hermiston Agricultural Experiment Station from 1963-1981. Several strategies were compared. The comparisons were made of the yields, water use, irrigation costs, net returns, risk and utility of the various strategies. The strategies were ranked according to maximum utility. The results indicated that designing irrigation systems for maximum yields did not result in the highest utility. The optimum strategies were those that initiated irrigation at a low level of soil moisture depletion and used a system with a relatively lower capital investment. The average annualized investment cost f or the five strategies with the highest yields was $76.43 per acre. The annualized investment cost for the five strategies with the highest utility was $57.54 per acre. The difference in average utility between the two groups was $19.37 per acre. The strategy with the highest yield had a utility level of $295.77 per acre. The strategy with the highest utility had a utility level of $337.12 per acre. The analysis included only those costs associated with irrigation. Utility was more sensitive to labor costs and water charges than to the cost of energy and interest rates. The level of risk aversion made very little difference in the relative level of utility for the different strategies. If the moisture holding capacity of the soil was reduced then the level of risk aversion made a bigger difference in the relative level of utility.
Estimating Irrigation Water Demand With A Multinomial Logit Selectivity Model
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Author :
language : en
Publisher:
Release Date : 2007
Estimating Irrigation Water Demand With A Multinomial Logit Selectivity Model written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
Understanding irrigation water demand is vital to policy decisions concerning water scarcity. This thesis evaluates irrigation water-use responses to changes in prices, while accounting for cross-sectional characteristics of irrigators' resource settings. An irrigator's profit-maximizing decision is modeled in two stages. In the first stage, he decides which crop to plant, and in the second stage he decides how much water to apply given the crop choice. This thesis employs an econometric modeling technique not previously used in the irrigation water demand literature, a multinomial logit selectivity model. This econometric technique allows the intensive (change in water use for each crop in the short run) and extensive (change in water use in the long run due to changes in crop-choice) margin effects to be computed in a simultaneous equation system. A multinomial logit selectivity model has applications to many resource issues in production agriculture where the two-stage decision process is common. The model is estimated from field-level data on water use and crop-choice for a 25-county region in western Kansas over the period 1991-2004. Water use was found to be highly inelastic to the price of natural gas, but becomes more elastic as the price increases. The intensive margin effect was significant for natural gas price. The extensive margin effect only comprised half the total effect under high natural gas prices and was negligible for low prices. However, the extensive margin effect under high natural gas prices declined over time due to more efficient irrigation systems and improved crop varieties. The intensive margin effect explained most of the water use response from changes in other variables, including corn price. An increase in corn price has a negligible extensive margin effect because corn is most often substituted with alfalfa, which has a similar water requirement. Inelastic demand implies that policies aiming to conserve the Ogallala Aquifer by increasing the price of water will not accomplish their purpose and will affect irrigators' incomes. More effective policies would be voluntary or mandatory quantity restrictions. However, efficient restrictions would need to account for spatial variation in the rate of depletion and the remaining saturated thickness.
Limitations To Efficient Water Use In Crop Production
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Author : Howard M. Taylor
language : en
Publisher:
Release Date : 1983
Limitations To Efficient Water Use In Crop Production written by Howard M. Taylor and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1983 with Technology & Engineering categories.