Extending the Economic Life of the Ogallala Aquifer with Water Conservation Policies in the Texas Panhandle

The continued decline in the availability of water from the Ogallala Aquifer in the Texas Panhandle has led to an increased interest in conservation policies designed to extend the life of the aquifer and sustain rural economies. Four counties were chosen for evaluation. This study evaluates the effectiveness of five policies in terms of changes in the saturated thickness, crop mix, water use per acre, and the net present value of farm profits over a 60-year planning horizon. The dynamic optimization models were developed using GAMS for the baseline as well as one for all five of the policy alternatives for each county. Results indicate that the policy scenarios of biotechnology adoption and a water use restriction will conserve the most water among the policies analyzed. In terms of economic returns, the biotechnology adoption policy by far provides the greatest benefit to producers due to yield increases that are estimated with current annual growth rates in new seed varieties. The water use restriction policy, on the other hand, has the lowest net present value of returns, indicating that conservation is accompanied with significant costs to producers. The irrigation adoption technology scenario is the next best policy in terms of net present value of returns (following biotechnology);however, it ranks last in terms of reducing aquifer depletion. It is important to note that while the models do not perfectly predict the factors being evaluated, it is the basis for comparison between the policy scenarios which are important. These comparisons will aid policy makers in determining the most effective strategy to conserve water while simultaneously considering the economic costs to producers. In addition, the results of this study can be applied to other areas facing similar conditions, either currently or in the future, throughout the Texas Panhandle.

Water Balance of Two Major Soil Types of the Texas High Plains: Implications for Dryland Crop Production

Crop production in the Texas High Plains is shifting from irrigated to dryland due to the increase of the depth to the water table from the Ogallala aquifer in regions where the saturated thickness of 9 m, the minimum to sustain irrigation, has been reached. Our objective was to use the mechanistic model ENWATBAL to evaluate the daily and annual water balance for three scenarios of rainfall in this region, a dry (189 mm), an average (449 mm) and a wet (669 mm) year. These three scenarios were applied to two major soil series of this region, Pullman and Amarillo. In all simulations, we used hourly input weather data for a location near Lubbock, Texas and used measured soil hydraulic properties to simulate the water balance for each soil series and the three rainfall scenarios. Results showed that in years with average and wet rain, storage of rainfall occurred in the Pullman but not in in the Amarillo soil series. However, storage of water could be enhanced by combining furrow dikes with minimum tillage along with crop covers that provide a surface residue. The implications of our results for dryland crop production in the semiarid climate of the THP suggest that for years with average and wetter rainfall soils in the Pullman series could store water that would be available for crop use. However, this was not the case for the Amarillo soil series and these soils represent a higher risk for dryland crop production.

The Impact of Discount Rate and Price on Intertemporal Groundwater Models in Southwest Kansas

Agriculture plays a vital role in the growth and development of the High Plains Region of the United States. With the development and adoption of irrigation technology, this region was transformed into one of the most agriculturally productive regions in the world [1]. The primary source of irrigation in this region is the Ogallala Aquifer. Currently, water from the aquifer is being used at a much faster rate than natural recharge can occur, resulting in a high rate of depletion from this finite resource. Depletion of scarce water resources will have a significant economic impact on the long-term sustainability of the region. The objective of this study is to evaluate the impact alternative prices and discount rates have on groundwater policy recommendations. Deterministic models of groundwater withdrawals were developed and used in order to analyze and evaluate the impact of high, average, and low crop prices in a status quo scenario as well as a policy scenario reducing irrigated acreage allocation. Furthermore, this study analyzes the effects and associated consequences of alternative discount rates on net and total revenue. As indicated by results of this study, alternative prices, costs, and discount rates utilized in a model have an effect on policy effectiveness.

Finger Millet: An Alternative Crop for the Southern High Plains

In the Southern High Plains, dairies are expanding to take advantage of favorable climatic conditions. Currently, corn (Zea mays L.) and forage sorghum [Sorghum bicolor (L.) Moench] are the two major crops grown in the region to meet silage demands for the expanding dairy industry, but they have relatively large water requirements of about 840 and 690 mm, respectively, to achieve desirable results. With rising energy costs and declining water levels in the underlying Ogallala Aquifer, crops that use less water, like finger millet (Eleusine coracana (L.) Gaertn) could become alternate forage crops for dairies to corn or forage silage. In this study, we evaluated the adaptability of five finger millet accessions to the Southern High Plains and compared nutritional quality of their forage to that of corn and sorghum. Results indicated that finger millet can be grown in the Southern High Plains. Comparison of nutrient composition has shown that the quality of finger millet is relatively higher than that of corn and sorghum in terms of calcium, potassium, and phosphorus levels in their forage. However, potential forage yield of most commonly grown corn and sorghum in the region is higher than that of finger millet. Therefore, finger millet may provide a unique opportunity to improve the dairy-fed silage quality by mixing it with corn or sorghum silage while meeting the growing regional forage demand. Further field research is needed to measure its water requirements in the Southern High Plains.

Modeling Resource Use Responses to Macroeconomic Changes: Water in the US Southern Great Plains

This study addressed the impacts of the 2008 US recession on water extraction rates from the Ogallala Aquifer in the Southern High Plains of Texas by examining the differences in projected macroeconomic variables and how they impact agricultural production and irrigation water use. The approach used pre- and post-recession FAPRI-based projections of commodity markets and an economic optimization model formulated for the Ogallala Aquifer to simulate water use adjustments. Results indicate that, based on the projections used, the 2008 recession decreased, then increased water use slightly in the representative counties, ceteris paribus, with minimal cumulative effect, and water use responsiveness to economic forces within the region was variable. This analysis also demonstrates that relating policy and economic changes to resource use changes is possible.

Annual Rainfall and Dryland Cotton Lint Yield—Southern High Plains of Texas

Agriculture in the Texas High Plains (THP) is in a transition phase of producing crops with a diminishing supply of irrigation-water from the Ogallala aquifer to dryland production systems. This shift is driven by the fact that the depth to the water table of the Ogallala aquifer continues to increase. Dryland cotton production systems are prevalent in the southern counties of the THP and our purpose was to use the long-term dryland cotton lint yields from these counties as precursors of the future cotton production patterns that will emerge in this region. For this purpose, from 1972 to 2018, we calculated the ratio of dryland cotton lint yield per unit of annual rainfall at the county level. This ratio is called crop water productivity (CWP) and has units of mass per unit volume (g/m3). In our analysis, we used cotton lint yield data provided by the National Agricultural Statistics and rainfall data provided by the National Oceanic and Atmospheric Administration. Our results indicated that the three datasets used in our analysis, i.e., cotton lint yield, rainfall and CWP were all normally distributed. In this time period, 1972 to 2018, only one year 2011—a year with a record drought of 179 mm of rain failed to produce a dryland cotton crop in all the counties used in our analysis. The mean cotton lint yield ± standard deviation ranged from a high of 400 ± 175 kg/ha in Lubbock County to a low of 252 ± 144 kg/ha in Andrews County. However, the counties with the largest CWP > 90 g/m3 were Glasscock, Midland and Martin County. The importance of this result is that these counties are in the southern region of the THP and are subject to extreme environmental conditions and yet cotton producers manage to produce a cotton crop in most years. We conclude that management production methods used by these dryland producers represent the future schemes that will need to be adopted in other counties to sustain the emerging dryland cropping systems across the THP.

美国西部奥加拉拉含水层水位下降原因初探

从奥加拉拉含水层的天然条件、开采量增加和地下水污染等方面进行分析,探究20世纪美国工农业蓬勃发展时期,奥加拉拉含水层地下水水位不断下降的原因,为更好地管理地下水开采提供依据。