Browsing by Author "Lacewell, R. D."

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The Agricultural Benefits of Salinity Control on the Red River of Texas and Oklahoma
(Texas Water Resources Institute, 1980-12) Moore, D. S.; Lacewell, R. D.; Laughlin, D. H.
Salinity of the waters from the Red River and its major tributaries has virtually eliminated its use for irrigation of agricultural crops in Texas and Oklahoma. A chloride control project has been proposed whereby the source salt waters will be captured and diverted to storage facilities. The purpose of this study was to estimate the net direct benefits to agricultural producers attributable to the proposed salinity control project. Further, estimates of project costs, municipal and industrial benefits and benefits from improving the water in Lake Kemp were obtained to complete a benefit-cost analysis. The procedure used to estimate agricultural benefits was to use a FORTRAN program to develop initial tableaus of a recursive linear programming model representing agricultural production in the study area. Alternative scenarios involving profit maximizing behavior on the part of producers, current cropping patterns, and with and without SAR crop yield effects were developed to provide a range of benefit estimates. The basis for benefit evaluation was to use parameters prescribed by the U.S. Water Resources Council's Principles and Standards and recent proposed changes along with those developed in this study to estimate the increase in net returns to producers in the study area between a with project and a without project condition for a 100 year period of analysis. Benefits were discounted to their present value with discount rates of 7 1/8 percent and 3 1/4 percent for comparative purposes. Benefits estimated herein were used in conjunction with external estimates of project costs and other benefits to evaluate the economic feasibility of the salinity control project. In all scenarios considered, cotton emerged as the major irrigated X crop. Scenarios involving profit maximizing behavior on the part of producers resulted in benefit estimates of over $65 million and $117 million without and with SAR crop yield effects, respectively, at the 7 1/8 percent discount rate. Under a constrained profit maximization scenario where SAR crop yield effects were included and in which producers were assumed to keep current cropping patterns in 1990, adjust to 50 percent of the optimal land use in 2000, and were fully adjusted to optimal land use by 2010, resulted in agricultural benefit estimates of over $87 million at the 7 1/8 percent discount rate. In a scenario where producers were assumed to maintain current cropping patterns throughout the 100 year period of analysis, benefits were estimated to be $28.8 million and $35.8 million without and with SAR crop yield effects, respectively, at the 7 1/8 percent discount rate. Benefit-cost analysis performed in this study indicated that the proposed project was economically feasible under assumptions of all scenarios considered except where current cropping patterns were followed for the entire analysis period. B/C ratios of 1.068 and 1.291 resulted for the profit maximization scenarios without and with SAR crop yield effects, respectively. Where benefits from the constrained scenario were included in the benefit-cost analysis, a B/C ratio of 1.162 resulted. Finally, with current cropping patterns maintained through 2090, B/C ratio estimates Of .907 and .938 resulted without and with SAR crop yield effects included, respectively.
Break-Even Investment in a Wind Energy Conversion System for an Irrigated Farm on the Texas High Plains
(Texas Water Resources Institute, 1981) Lacewell, R. D.; Hardin, D. C.
The purpose of this study was to quantify the benefits of using a wind energy system for irrigation. The value of wind energy was estimated on both a static basis (where the annual value of wind power was assumed to be constant over the life of the machine) and on a temporal basis (where the annual value of wind power was estimated recursively). The model for static analysis contained two components which were applied consecutively. The first was a linear programming (LP) model for the High Plains region. Production activities were included which allowed both optimal and non-optimal timing of post-plant irrigations, giving the producer added flexibility in the employment of limiting water resources. The optimal irrigation schedule determined by the LP solution was used as input to the second component. A simulation model matched stochastically generated estimates of wind power availability with irrigation fuel requirements (derived from the profit maximizing irrigation schedule) by three-hour time periods throughout a year. For the temporal analysis, a Fortran subroutine was added to the LP model to operate the model recursively over the life of the wind system and to account for the annual decline of the aquifer. Both fixed and variable costs were included. The basic LP model was applied to develop the benchmark case (i.e., without wind power). The farm operation with wind power was analyzed by applying the LP model with the monthly expectations of wind-generated electricity added. Two wind machines were analyzed, with rate outputs of 40 to 60 kilowatts (KW). Each was applied to the Northern and Southern Texas High Plains over a range of land and water resource situations. Breakeven investment was estimated at discount rates of three, five and ten percent. Cropping patterns on the Southern High Plains were dominated by irrigated cotton and were insensitive to changes in crop or electricity prices. On the Northern High Plains, irrigated corn and grain sorghum were the major crops, with acreage reverting to dryland wheat at the higher electricity prices. The cropping patterns in this area were impacted heavily by labor restrictions. Consideration of wind power had little effect in determining optimal cropping patterns. When wind power was applied to an irrigated farm on a static basis, the set of crop prices applied had little effect on the annual value of a wind system. Value of wind power was increased, but by smaller proportions than associated increases in the price of electricity. Each machine size had a greater value when operated on the larger of the two applicable land units (100 acres for the 40 KW machine and 144 acres for the 60 KW system). The 60 KW system was also tested on the 100 acre unit but returned less per KW than the 40 KW system. Available wind power in the temporal analysis was less than in the static analysis, thus temporal estimates of wind system value should be regarded as conservative. On the Southern High Plains, break-even investment was decreased slightly from the static analysis. However, in some situations on the Northern High Plains, break-even investment increased. This indicates that the value of wind power could increase as the aquifer declines in some situations. Break-even investment increased by up to 80 percent when the price of electricity was increased by $.005 per KWH per year. The most significant effect of wind power was that it allowed the maintenance of irrigation levels which, without wind power, had been made uneconomical. These results indicate that, at least in the future when wind system costs decrease and stabilize, wind-assisted irrigation could be an economically viable alternative for Texas High Plains producers. The results are limited by the need for future research regarding the effect of irrigation timing on crop yield as well as some of the long-term characteristics of wind system operation, such as durability and the requirements and costs for system repairs and maintenance.
An Economic Analysis of Erosion and Sediment Damage in the Lower Running Draw Watershed
(Texas Water Resources Institute, 1978-08) Mueller, P. E.; Lacewell, R. D.; Harris, B. L.; Reneau, D. R.; Taylor, C. R.
The development and implementation of agricultural non-point source (NPS) pollution control plans was mandated by the 1972 Federal Pollution Control Act Amendments, Public Law 92-500. The purpose of this particular report is to present the results of a study on the economic impact of implementing potential agricultural NPS pollution controls in Lower Running Water Draw watershed. The study focuses on: (a) the effects of erosion control on farm income, (b) off-site sediment damages in the watershed; (c) the costs of administering and enforcing alternative erosion controls, and (d) on-farm economics of soil conservation practices. Erosion controls considered include the traditional voluntary programs combined with economic incentives as well as possible regulatory programs. The focus of the study is on erosion and sedimentation because sediment is a potential transporter of pollutants. Practices to control agricultural non-point source pollution would probably be aimed at reducing soil loss. Conservation and conservation related practices are, at present, considered the best technical practices to abate agricultural non-point source pollution. This is a study of both conservation and environmental economics, two areas that tend to be closely related. For this project, the concern was over potential pollution (an off-site problem), but because of long-run farm income consequences, this concern cannot be separated from conservation problems (an on-farm problem). Accordingly, the report contains substantial information on the short and long-run on-farm benefits and costs of various soil conservation practices for the specific soil mapping units in Lower Running Water Draw watershed. The results of this study are applicable to the majority of the soils in the High Plains Land Resource Area. Only sheet and rill erosion are considered in the study. The first section of the report describes the selected "Best Management Practices" and examines the on-farm economics of soil conservation. The second section postulates various sediment damage control options and models the economic consequences of implementation, both to agricultural producers as a group, and to society.
An Economic Feasibility Study of Irrigated Crop Production in the Pecos Valley of Texas
(Texas Water Resources Institute, 1979-03) Whitson, R. E.; Lindsey, K.; Hardin, D. C.; Lacewell, R. D.; Condra, G. D.
Public concern over the potential effects of energy price increases on the U.S. food and fiber system has been dramatically justified in the Trans Pecos region of Texas where a 450 percent increase in the price of natural gas was followed by the idling of thousands of irrigated acres and the departure of many of the farmers. This study was conducted to provide the answers to two questions: (l) Can an irrigated farm survive in the Trans Pecos? and (2) If it survives, how profitable will it be? Coyanosa, one of the irrigated areas of the Trans Pecos, was selected as a study area, and the St. Lawrence area of the Edwards Plateau was selected to provide comparative estimates of survival and profitability. A modified MOTAD linear programming-simulation model was developed to generate estimates of survival and profitability by recursive simulation of multiple time periods, as follows: (l) development of a farm plan, (2) generation of stochastic prices and yields, (3) simulation and evaluation of the farm plan in operation, and (4) update of the planning situation to reflect adjustments in expected prices, expected yields, and credit restrictions. The model then returns to step l for simulation of the next time period. The model was applied to the Coyanosa and St. Lawrence regions under alternative future scenarios for inflation rates, energy prices, crop prices, and interest rates. The Coyanosa model was also applied under most likely scenario conditions to analyze the effects of alternative levels of risk-aversion and alternative tenure situations. Each application included 20 simulations of a 1O year planning horizon to develop a distribution of outcome. The Coyanosa farm survived about 8 years under the optimistic scenario and 5 years under all other scenarios. The most likely rate of survival was 20-30 percent with a range of 1O percent to 65 percent for other scenarios. The average life and rate of survival was higher for the St. Lawrence farm under all scenarios. The internal rate of return on equity capital for the Coyanosa farm was 36.8 percent under the optimistic scenario and negative under all other scenarios. The rate of return for St. Lawrence was not significantly different for the optimistic scenario; however, it was higher than Coyanosa for all other scenarios. The level of risk-aversion described by the baseline model appears to be relatively high compared to other studies, but there are indications that it may be relatively low for the St. Lawrence area. Both rate of return and survival increased in response to decreased levels of risk-aversion, however, the latter result may be related to the specification of the risk restraint. Land purchase provided higher estimates of survival and profitability than rental or combined rental and purchase. These results seem to relate to the finding that traditional crop share rental arrangements are unsatisfactory for the Coyanosa area. It was concluded from this study that (l) survival and profitability of irrigated crop production in the Coyanosa area will depend greatly upon future levels of inflation, energy prices, crop prices, and interest rates, (2) survival and profitability for Coyanosa will most likely be lower than St. Lawrence, and (3) land purchase provides greater potential survival and profitability than traditional crop share rental arrangements. These conclusions were limited by need for additional research regarding the effects of beginning equity levels and consideration of risk in farm planning. Conclusions were also limited by the data and assumptions utilized in the study.
Economic Implications of Farmer Storage of Surface Irrigation Water in Federal Projects: El Paso County, Texas
(Texas Water Resources Institute, 1981-12) Lacewell, R. D.; Cornforth, G. C.
The Bureau of Reclamation has approved a program for farmer storage of surface irrigation water in Elephant Butte Reservoir, New Mexico. This program would allow individual farmers to store part of their annual surface water allotment in the reservoir subject to evaporation loss to be drawn at a future date upon request. The purpose of this study is to ascertain the economic implications of such a program for farmers in the El Paso County Water Improvement District No. 1. The economic analysis was based on results from a linear programming model developed for crop production in E1 Paso County. The model was designed to maximize net farm revenue. Twelve crops were included in the analysis. The effects of soil type and salinity level of irrigation water on crop yields for all twelve crops were estimated. Input requirements by crop and yield level were identified. Input categories included seed, chemical, water, machinery, labor, harvest, other and fixed costs. Irrigation alternatives included both surface and ground sources. In addition, the water saving technology of laser leveling was incorporated into the model. The model was restricted by acreage of a soil group with a specified level of salinity in the underlying groundwater. Also, the quantity of surface irrigation water available was limited. This static linear programming model was applied for various surface irrigation water allocations ranging from zero to three acre feet per acre of cropland with groundwater assumed available. This procedure produced a schedule of net farm revenues for alternative surface irrigation water allocations for use in conjunction with groundwater. The procedure was repeated with groundwater availability limited to zero. These two schedules of net farm revenues were then used (1) to form the basis of two temporal linear programming models which maximized the real value in 1980 dollars of a stream of net farm revenues, and (23 to evaluate a specified annual surface irrigation water use scenario of two acre feet per acre per year. The temporal models maximized the 1980 real value of net farm revenues. This revenue stream was generated by optimal temporal use of the actual annual surface irrigation water allotments for 1963 to 1980. This optimal use includes the opportunity to store water in Elephant Butte Reservoir subject to evaporation. Results were obtained both with and without groundwater pumping over three surface water use scenarios (actual, optimal temporal and two acre feet per year). The results of this study indicated that, with the ability to store surface water, temporally optimizing surface water use would have increased the real value of net farm revenue $0.84 per acre per year or 0.4 percent above the real value of net farm returns implied by the actual use rates for the groundwater pumping case. For the no groundwater pumping case, the real value of net farm returns increased by $3.56 per acre per year or 2 percent above the net farm returns indicated by the actual use rates. Also, storing surface water for future use, or accumulation, tends to decrease the year to year variability of net farm revenues. Groundwater pumping is also known to decrease this variability. The target surface water allocation of the project administrators is three acre feet per year. The optimal temporal solutions tended to be between this three acre feet allocation and the two acre feet allocation as specified in the two acre feet per year scenario. An optimal temporal allotment of three acre feet appears too high while two acre feet appears too low. Without a system of farmer-held surface water storage, optimizing temporal use of surface irrigation water would not be possible. Thus, this water storage opportunity is an important irrigation management tool for individual farmers in the El Paso County Water Improvement District No. 1.
Economic Implications of Farmer Storage of Surface Water in Federal Projects: Elephant Butte Irrigahon District, Dona Ana and Sierra Counties, New Mexico
(Texas Water Resources Institute, 1982-12) Lacewell, R. D.; Teague, P. W.; Ellis, J. R.
This study estimated the expected regional impact and economic feasibility of a proposed water accumulation or water saving option for agricultural producers operating in the Elephant Butte Irrigation District in southern New Mexico. The water accumulation plan would allow agricultural producers to retain part of a given year's surface water allocation in Elephant Butte Reservoir, providing use of the unevaporated portion in a later year. The analysis was based upon modeling of current cropping practices subject to regional resource constraints within a static linear programming model. Pertinent input/output coefficients and costs were incorporated, with five-year (1976-1980) average output prices assumed for twelve crops spread across 11 soil groups. Applicable fixed costs and interest charges were taken into account. Net returns to the region were maximized assuming 1 and 3 acre-feet of groundwater available per year per acre irrigated. Surface water availability was varied from zero to 3 acre-feet per acre to obtain schedules depicting regional net returns and cropping patterns for varying surface water allocations for both the groundwater situations examined. These schedules were then used to build temporal linear programming models which maximized the present value of net returns for the period 1963 to 1980 subject to historical surface water allocations and reservoir evaporation rates. Calculation of these evaporation rates took into consideration increased lake levels due to surface water storage. The temporal models were used to estimate an optimal allocation of surface water over the 18 year period investigated for the two groundwater availability situations considered. Returns for the optimal surface water allocations were then upper bounds on potential net returns to the region. Projected streams of net returns were also obtained for each of the scenarios analyzed; i.e., optimal temporal allocation of surface water, 2 acre feet of surface water per year limit and actual allocation of surface water given the 1 and 3 foot groundwater limitations. These streams of net returns were valued in 1980 dollars allowing comparison among the alternative scenarios. Differences between the various returns streams for each groundwater situation provided a measure of possible economic effects of the water saving program. Results of the study for current groundwater availability conditions indicate that optimally temporal allocated surface water use would increase average annualized net returns per acre from that of the actual surface water allocation by .82 dollars per year, or less than .2 %. Use of the more realistic two acre-foot per acre limit on surface water use led to an increase in annualized net returns of only .23 dollars per acre per year. Both increases were deemed insufficient to cover anticipated administrative costs of the program. Under conditions of limited groundwater availability (1 acre-foot per acre), percentage increases in annualized net returns over those for the actual surface water allocation were more significant. Use of the water saving option and perfect knowledge of future surface water allocations resulted in increased annualized net returns of $8.41 per acre per year for an increase of 54 z. For the two acre-foot surface water use limitation case, annualized net returns increased by $3.68 per acre per year (23.7 %). In all cases considered, groundwater use increased with use of the water saving option. These economic results, coupled with possible political obstacles faced by the program, suggested that alternative water management schemes should be considered.
Economic Implications of New Crops, Row Damming and Land Clearing in the Texas Winter Garden
(Texas Water Resources Institute, 1983-02) Pena, J. G.; Cornforth, G. C.; Lacewell, R. D.; Muncrief, G.E.
The chief sources of groundwater for the Texas Winter Garden are the Carrizo (Dimmit, Zavala, Frio, and LaSalle Counties) and Edwards (Uvalde County) Aquifers. The major user of groundwater in the region is irrigation. However, insufficient aquifer recharge relative to groundwater use has stimulated interest in alternatives to ease adjustments to diminished groundwater supplies. The impact on net revenue, groundwater utilization, and land use of new crops (guar, guayule, and short-season irrigated cotton), row damming, and conversion of range to cropland was evaluated using a regional linear programming model. Temporal analysis, 1981-2001, incorporated changes in groundwater availability, static groundwater levels, and corresponding fixed and variable costs. Introduction of guar and short-season irrigated cotton (base solution) was associated with increased groundwater pumpage from the Carrizo Aquifer, increased net revenue, and increased irrigated acreages. Edwards Aquifer pumpage remained constant at an upper limit. When guayule entered the base solution, net revenue rose by four million dollars and groundwater pumpage and irrigated acreages declined only in the Carrizo Aquifer. Land clearing without guayule added 17, 25.2, and 26.3 million dollars to net revenue for light; light and medium; and light, medium, and heavy brush clearing; respectively. Under light brush clearing about 480,000 acres were added to cropland and groundwater pumpage remained steady. Pumpage increased under the other land clearing activities. Land clearing with guayule almost doubled net revenue compared to land clearing without guayule. Row damming was the most effective alternative in reducing dependence on groundwater. Row damming in dryland grain sorghum and dryland cotton decreased groundwater pumpage and increased net returns above the base by 6.7 million dollars without land clearing and 18.6, 30.3, and 32.9 million dollars with the respective land clearing alternatives. Carrizo Aquifer groundwater pumpage was significantly reduced in each of the four alternatives and Edwards pumpage was reduced in all but the heavy brush clearing alternative. Under temporal and static analysis for projected (forecast) groundwater pumpage, net revenue, groundwater pumpage, and irrigated acres exceeded those of solutions with restricted (forced conservation) groundwater. Carrizo Aquifer groundwater pumpage was greater under restricted than in the projected groundwater scenarios.
Economically Optimum Agricultural Utilization of a Reclaimed Water Resource in the Texas Rolling Plains
(Texas Water Resources Institute, 1980-09) Lacewell, R. D.; Taylor, C. R.; Zacharias, T.
The U.S. Army Corps of Engineers (COE) has proposed a project that would reduce the flow from saline springs and seeps within the groundwater alluvium of the Red River Basin. While the amount of salts moving through the alluvium would be controlled by the project, total water quantity would not be appreciably affected. Presently, salinity levels in the basin are quite high, making irrigated agriculture an infeasible alternative. In areas affected by salinity, salts accumulate in the active root zone, thereby restricting the availability of soil moisture to the crop and reducing yield. To counteract the deleterious presence of the salts, extra irrigation water is applied to "leach" the salts below the active root zone thus maintaining the yield at some specified level. Waters containing over 13,000 parts per million (ppm) salts have been sampled by the COE in the Pease River watershed (a subsector of the entire area to be impacted by the project). It is estimated that installation of the project would reduce this level to approximately 3000 ppm. Although 3000 ppm is not below the tolerance threshold of most plants, rainfall in the area is sufficient to act as a natural leaching agent. The purpose of this study was to estimate the response of the agricultural sector to the project. A recursive linear program was designed in such a manner that the time path of producer adjustments to the reclaimed water source could be estimated. The Pease River watershed was chosen due to the sizable reduction in the salinity due to the proposed project, relative to other areas within the basin. By considering only a single watershed, the adoption process could be more closely studied. Two scenarios were considered in the analysis in an attempt to better understand the effects of the initial assumptions on the measure of project benefits. The first scenario applied guidelines established by the Water Resources Council (WRC). WRC guidelines required the use of OBERS SERIES E' yield projections, normalized prices, and an interest rate of 7.125 percent to discount future costs and benefits. The second scenario applied in alternative criteria, which assumed no trend in yield, a three-year average of current prices, and a real interest rate of 2.5 percent. Since probabilistic estimates indicating the improvement in water quality through time were unavailable from the COE, it was assumed that all improvement in water quality occurred linearly over time, with full water quality improvement in the tenth year. The adjustment process was then evaluated over a twenty year horizon. Several irrigation strategies were considered for each crop, thereby allowing the model to select an optimal leaching policy given the level of water quality for any point in time. The linear programming model maximized expected net returns from representative crop enterprises on the basis of a three-year moving average of past actual yields. This means expected yield in the linear programming model was slightly less than actual yield for any particular year. When all improvements in water quality had taken place and the model achieved steady state, the economically optimal allocation of the water resource had been determined. Results from the study indicated that a policy of rapid adoption should be undertaken. In the initial year, a 40 percent leaching fraction was economically feasible on limited acreage. Dryland production then shifted quickly to irrigation as water quality improved. Water use also shifted, moving from a 40 percent to a 20 percent leaching fraction. By the ninth year of the analysis, all adjustment's had occurred and a 10 percent leaching fraction was economically optimal on all irrigated acreage. Due to its profitability and for relative salt tolerance, cotton was the only irrigated activity chosen by the model. An optimal cropping pattern of 55,121 acres of irrigated cotton, 14,437 acres of dryland cotton and 7,728 acres of native pasture was selected by the model under the first scenario. For the second, scenario, the optimal cropping pattern consisted of 55,703 acres of irrigated cotton and 25,583 acres of dryland alfalfa. The estimated net present value of benefits attributable to the project over the 20 year planning horizon was approximately $16 million and $30 million for the first and second scenarios, respectively.
Economically Optimum Irrigation Patternsfor Grain Sorghum Production: Texas High Plains
(Texas Water Resources Institute, 1979-03) Zavaleta, L. R.; Lacewell, R. D.; Taylor, C. R.
Agricultural production and associated economic effects of irrigation on the Texas High Plains are seriously threatened by a rapidly declining groundwater supply and a swift upward trend in energy costs. To optimize the amount of irrigation water to be applied during specified periods of the production process, a stochastic open-loop feedback control policy was built into a grain sorghum growth simulation model. The control policy operated under the basis of constant revision of the expectations generated at every starting point for each of the production periods. If discrepancies between the expected and the realized values existed, then, based on current conditions a reevaluation of the control variable, irrigation water, was made and the decision for the first period adopted. This process continued throughout each period of the growing season. Within the stochastic policy designed, the values for the control variable were obtained by numerical search. The model was applied to estimate optimal irrigation strategies and the impact of fuel curtailments on them. Initially, optimal irrigation strategies were developed under the assumption of perfect knowledge. Under this assumption, the results indicated there was not a unique strategy to be applied at all times. The quantities of irrigation water to apply at each period depended on the initial or starting conditions. Since one of the purposes of building the model was to make it perform under stochastic or real world conditions, the assumption of complete knowledge was relaxed to consider the case where the climatic environment was unknown. As in the deterministic case, the optimal amounts of irrigation water, by period. It was also observed, that with the open-loop feedback control, the results obtained for yields did not differ substantially from those obtained in the perfect knowledge case. The discrepancies among the two cases were primarily in the optimal amount of water applied and therefore in net returns. In the stochastic case, the use of irrigation water had a mean value approximately 25 percent more than in the case of perfect knowledge. The effect of a fuel or irrigation curtailment was estimated for alternative time spans. When curtailments had a length of 10 days, there were no perceptible changes in the amount of net returns or yields, as compared to the no-curtailment case. The implication drawn was that by having frequent irrigation periods and applying optimal amounts of water, the adverse effects of 10-day curtailment periods were buffered. The cases of twenty and thirty-day periods were found to have highly negative effects on the outcomes, especially net revenues, which decreased about 50 percent (from $99 to $50) in the curtailment case of 40 - 70 days after plant emergence compared to the no-curtailment value. The effects were not only on a decreased amount of returns perceived but also on an increased spectrum of relative fluctuation (from 18 percent to 68 percent for the same situations mentioned above). It was also found that for the same time-span type of curtailments the effects were conditioned to the period in which they Occurred. However, the 20 or 30 day curtailment period might be applicable to much shorter actual fuel curtailment periods. Producers lose not only the time of fuel curtailments, but also, they must cover many acres with a limited number of wells. As a result, a 10-day fuel curtailment could easily result in a 20 to 30 day delayed irrigation. To summarize, improved irrigation distribution technology could result in increased yields and less irrigation water by simply having very close control on timing and quantity of water applied.
Establishing Crop Acreage Flexibility Restraints for Subregions of the Texas High Plains
(Texas Water Resources Institute, 1977-01) Lacewell, R. D.; Condra, G. D.
Cropping pattern shifts in many aggregate linear programming (LP) models need to be constrained due to institutional, marketing machinery, and price uncertainty factors. The purpose of this study was to estimate constraints which are referred to as flexibility restraints for major crop acreages in subregions of the Texas High Plains for use in a LP model that was developed to derive water and other input demand. Alternative estimating models for establishing acreage flexibility restraints were developed using methodology and model formulation presented in the literature. The results of these models in estimating flexibility restraints were evaluated using statistical measures and subjective analysis. Models which were analyzed ranged from a simple linear regression model in which the current year's acreage is expressed as a function of last year's acreage to a multiple regression model in which economic and climatological variables were considered. The multiple regression model as formulated and estimated did not provide satisfactory results. However, as in many of the earlier studies the simpler models did provide acceptable performance. From among the simpler models one was selected based on statistical measures and a prioria expectations. The model was used to calculate crop acreage flexibility restraints for three subregions of the Texas High Plains.
Impact of Alternative Energy Prices, Tenure Arrangements and Irrigation Technologies on a Typical Texas High Plains Farm
(Texas Water Resources Institute, 1980-05) Whitson, R. E.; Hardin, D. C.; Lacewell, R. D.; Petty, J. A.
Irrigation is a major contributing factor in crop production on the Texas High Plains. It is responsible for greatly increasing crop production and farm income for the region. Two factors, a declining groundwater supply and increasing production costs, are of primary concern because they impact on farm operations and producer economic viability. A recursive linear programming model for a typical Texas High Plains irrigated farm was developed to evaluate expected impact of price changes, tenure and new technology. The model includes a Fortran sub-routine that adjusts irrigation factors each year based on the linear programming solution of the previous year. After calculating new pumping energy requirements, well yield, and pumping lift, the Fortran component updates the linear programming model. This procedure continues automatically to the end of a specified planning period or to economic exhaustion of the groundwater, whichever occurs first. Static applications of the model, in a deep water situation, showed that a natural gas price increase from $1.50 to $2.20 per thousand cubic feet (mcf) would result in reductions in irrigation levels. Irrigation was terminated when the price of natural gas reached about $7.00 per mcf. In a shallow water situation, much higher natural gas prices were reached ($3.60 per mcf) before short-run adjustments in farm organization began to occur. Under furrow irrigation, irrigation was terminated when the natural gas price reached $7.00 per mcf. Increased natural gas prices impact heavily on returns above variable costs (up to 15 percent reductions) for a 60 percent natural gas price increase. The effects of rising natural gas prices over a longer period of time were more significant. Annual returns (above variable and fixed costs) were reduced by as much as 30 percent, and the present value of returns to water was reduced by as much as 80 percent as the natural gas price was increased annually by $0.25 per mcf (from $1.50 per mcf). The economic life of deep groundwater was shortened by as much as 18 years. Renter-operators are even more vulnerable to rising natural gas prices than are owner-operators. With rising natural gas prices, profitability over time for the renter is low. As natural gas prices continue to increase, the greater will be the incentives for renter-operators to seek more favorable rental terms such as a sharing of irrigation costs. With the problem of a declining groundwater supply and rising natural gas prices, an economic incentive exists for producers to find new technologies that will enable them to make more efficient use of remaining groundwater and of natural gas. Substantial economic gains appear feasible through improved pump efficiency. Increasing pump efficiency from 50 to 75 percent will not increase the economic life of the water supply, but can improve farm profits over time; e.g., the present value of groundwater was increased 33 percent for a typical farm with an aquifer containing 250 feet of saturated thickness and 15 percent for 75 feet of saturated thickness. Improved irrigation distribution systems can help conserve water and reduce irrigation costs. Results indicate that irrigation can be extended by 11 or more years with 50 percent improved distribution efficiency. In addition, the increase in present value of groundwater on the 1.69 million irrigated acres of the Texas High Plains was estimated to be $995 million with 50 percent improved efficiency. Limitations in borrowing can substantially reduce annual net returns. This analysis suggests that the farmer can economically justify very high costs of borrowing rather than a limitation of funds available for operating expenses.
The Impact of Energy Shortage and Cost on Irrigation for the High Plains and Trans Pecos Regions of Texas
(Texas Water Resources Institute, 1978) Petty, J. A.; Zavaleta, L.; Hardin, D. C.; Condra, G. D.; Lacewell, R. D.
The High Plains and Trans Pecos regions of Texas are semi-arid crop production regions located in the western part of the state. Relatively low levels of rainfall are supplemented by irrigation from groundwater supplies. These regions produced 51 percent of the cotton, 42 percent of the grain sorghum, and 48 percent of the wheat produced in Texas in 1974 (Texas Crop and Livestock Reporting Service). Considering only irrigated production these percentages were 75, 85, and 91 percent of Texas irrigated crop production for cotton, grain sorghum and wheat respectively. The importance of the High Plains and Trans Pecos regions to Texas crop production are not limited to these three crops, however, these statistics do serve to illustrate the significance of these regions in the Texas agricultural economy. While it is easily seen that the majority of irrigated production (for the crops mentioned) in Texas occurs in these regions, it should be noted that the importance of irrigation in the High Plains and Trans Pecos regional economies is much greater than these statistics show. On the High Plains 86 percent of the cotton, 90 percent of the grain sorghum, and 75 percent of the wheat produced in 1974 was harvested from irrigated acreage. Rainfall is somewhat less in the Trans Pecos region and 100 percent of the production of these crops was under irrigation (Texas Crop and Livestock Reporting Service). More than 60 percent of the value of agricultural crops in Texas is produced on irrigated land (Knutson, et.al.). Thus, the crop production of these regions is vitally important to the Texas and respective regional economies. Crop yields are heavily dependent on groundwater irrigation and extremely sensitive to any factor which may affect the availability or cost of irrigation water. Availability and price of fuel used in pumping groundwater are the critical factors which directly affect the availability and cost of irrigation water. About 39 percent of the energy used in Texas agriculture in 1973 was utilized in pumping water, compared to 18 percent used in machinery operations. Of this irrigation fuel, 76 percent was natural gas, the majority of which was consumed in the High Plains (Coble and LePori). Current supplies and reserves of natural gas have reached critically low levels in recent years and producers in the High Plains and Trans Pecos regions are faced with possible curtailments of, and certain price increases for their irrigation fuel (Patton and Lacewell). The threat of possible curtailment of fuel supplies during the irrigation season imposes greatly increased risk to irrigated crop production since curtailment of natural gas supplies during a critical water use period would significantly reduce yields (Lacewell). This threat would also increase financial risk and restrict availability of credit. Continued price increases for natural gas will increase costs of pumping irrigation water and hence the costs of irrigated crop production (Patton and Lacewell). The Ogalalla aquifer underlying the High Plains and many of the alluvium aquifers underlying the Trans Pecos are exhaustible; i.e., there is a negligible recharge from percolation and other sources. Therefore, even with unchanged natural gas prices, these groundwater supplies are being "economically" exhausted over time as pumping depth increases. Increases in fuel prices will lead to reduced groundwater pumpage and result in less groundwater being economically recoverable. Although life of the physical supply will be exhausted, a greater quantity of groundwater will be economically unrecoverable for irrigation without significant product price increases.
Impact of New Irrigation Technology on the Texas High Plains: 1980-2020
(Texas Water Resources Institute, 1983-12) Ellis, J. R.; Lacewell, R. D.; Reneau, D. R.
Crop production on the Texas High Plains is constrained by limited and erratic rainfall, hence irrigation is important. Presently, 6 million acres, or 50% of regional cropland, are irrigated annually. Irrigation water is drawn from the Ogallala Aquifer, which has a recharge rate near zero, and is being depleted at the present rate of use. Future crop production is dependent on technology, as well as the resources available. Because water is a major limiting resource, technologies that increase plant available water, such as advanced irrigation distribution systems and soil moisture conserving tillage methods, are of particular interest, and are the focus of this study. Two levels of analysis were included. The first, a farm level analysis based upon representative counties showed the similarities and differences of response given particular resource endowments, technological options and price situations. Part of the analysis considers the impact of annual qroundwater withdrawal constraints on discounted net present value for a forty year planning horizon. The discounted net revenue was higher for lower discount rates, better commodity prices, and more advanced technology. However, alternative discount rates, prices, and technology did not change the optimum annual withdrawal limit. Lower initial groundwater resources reduced the revenue level and the optimal annual groundwater decline limit. The other part of the farm firm analysis covers expected costs, returns and cropping patterns for a single period. Prices have a significant influence on production, but a far greater impact on net returns. The value of production is 64% to 85% higher for normal prices versus low prices, while net returns are from 8 to 30 times higher. The amount of available groundwater was not as important as price in the determination of production levels, but it too had a significant impact on net returns. Comparing across representative counties, with prices, technology and groundwater situations held constant, the value of production varied more than $150 per acre, but net returns changed very little. The value of production increases 17% with advanced technology, but net revenue more than doubles. The second level of analysis, a regional analysis, addressed expected changes in cropland use, groundwater pumpage, production levels, input demand, and farm income over the next forty years, under select technology and price assumptions. Water availability and hence use, drops over time, reducing irrigated cropland, gross returns and net revenue. The demand for other inputs does not decline as quickly as water usage, indicating input substitution. Further, the decline in net revenue is greater than the reduction in gross returns or variable costs of production. The intensity of crop production declines and the mix of crops changes, reducing purchased input demand and lowering regional farm income. Advanced technology enhances the value of the groundwater resource, increasing water use especially in the later periods of the time horizon. Nontheless, over the whole 40 years, technologies which improve dryland, as well as irrigated, crop production, such as limited tillage and crop rotations, have a greater impact than advanced irrigation technology. While advanced technology enhances productivity and increases net returns, technology is not a substitute for irrigation. Nor does technology save groundwater resources in the large, since the increased value of the water, given advanced technology, encourages greater use, overall. Advanced technology, however, is important to the future of crop production in the region, since it increased the level of production, and net revenue. Further, the impact of technology was proportionally greater under the low commodity price scenarios than for average prices.
Outlook for Energy and Implications for Irrigated Agriculture
(Texas Water Resources Institute, 1977-09) Lacewell, R. D.; Patton, W. P.
Agriculture uses large quantities of energy to pump groundwater for irrigation. This means the cost of energy has important implications for the industry in terms of costs and profitability. Increases in the prices of energy sources such as natural gas, electricity, liquid petroleum gas and diesel can cause economic hardship for irrigators, particularly if those increases are unanticipated. The purpose of this paper is to briefly summarize important trends in the current domestic energy situation that could have significant impacts on the future cost and availability of energy, and to show what the implications of those trends are for irrigated agriculture. The primary focus of this study will be on trends in natural gas, since natural gas is the major fuel used for irrigation in the Great Plains states.
Recursive Programming Model for Crop Production on the Texas High Plains
(Texas Water Resources Institute, 1984-02) Ellis, J. R.; Lacewell, R. D.; Reneau, D. R.
A flexible, recursive programming model of crop production on the Texas High Plains was developed. Besides the linear programming (LP) Optimization routine and recursive feedback section, the model also includes a matrix generator and report writer to make scenario definition and output analysts faster and easier. The production activities for each run of the model, are defined for one acre of a specific crop or crop rotation, irrigated at particular times, using a chosen irrigation distribution system and tillage method, on a given land class. The irrigation level may be zero (i.e. dryland) and the land class can include terracing when appropriate. The objective function for the LP optimization routine is the maximization of net returns (gross returns minus all variable, or variable and fixed, costs) to land, water and management. For static runs, the maximization includes net returns over variable costs only; for temporal runs, over variable and fixed costs. LP constraints include land by soil class, irrigation water availability for each of 18 irrigation periods and a total annual water use constraint. The model can be run as either a static single period optimization or as a recursive, temporal model When operated in the recursive mode, the model will loop through up to 20 iterations, rebuilding the LP matrix for each iteration and writing a report for each period. The feedback section of the recursive model is used to update the groundwater situation after solution of each iteration. The amount of groundwater used is summed and that usage translated into the reduction in aquifer saturated thickness, increased pump lift and reduced well yield per period. The new groundwater situation plus any inputted changes in prices, technical efficiencies or crop yields form the data, from which the production activities and constraints for the next iteration are built. At the end of the prescribed number of iterations, a summary report covering the whole time horizon is written and the discounted present value of net returns is calculated at three prescribed discount rates.