© 2007 Plant Management Network.
A Pasture-Based Model for Extended Drought Management, Long-Term Sustainability, and Economic Viability in the Southern High Plains
Carlos Ortega-Ochoa, Facultad de Zootecnia, Universidad Autónoma de Chihuahua, Perif. Fco R. Almada Km. 1 C.P. 31031 Admon Correos 4-28 Chihuahua, Chih., México; and Michael C. Farmer, Department of Agricultural and Applied Economics, and Carlos Villalobos, Department of Natural Resources Management, Texas Tech University, Lubbock 79409
Corresponding author: Carlos Villalobos. firstname.lastname@example.org
Ortega-Ochoa, C., Farmer, M. C., and Villalobos, C. 2007. A pasture-based model for extended drought management, long-term sustainability, and economic viability in the southern High Plains. Online. Forage and Grazinglands doi:10.1094/FG-2007-1108-01-MG.
Declines in water levels in the Ogallala aquifer will require production alternatives to irrigated agriculture on the Southern High Plains. This underscores an imperative to develop explicit drought management protocols. To meet this challenge we introduce a proof-of-concept drought management protocol for a forage-based rangeland beef production process that operates in concert with a multi-product cash crop system. Initial findings suggest the system is more profitable than dryland cotton and nearly as profitable as irrigated cotton today. The use of native rangeland and WW-B.Dahl bluestems on the range and the intensive multi-crop system with reduced irrigation are independently research-validated models. The immediate benefit of the protocol is that the integrated system withstands a protracted drought, implemented in phases to minimize disruption. The plan relies on blending native rangeland and WW-B.Dahl old world bluestem pastures on the range. Beef production integrates into the cropping system to supply nitrogen while cattle access forages. To sustain a two-year drought, our program moves animals among native rangeland, WW-B.Dahl-improved pastures, and the cropping system to sustain herd size. Incorporating WW-B.Dahl into the drought plan diversifies choices, lowers economic risks of the integrated system and encourages more ecologically sound native rangeland management.
The low recharge rate of the Ogallala aquifer beneath the Southern High Plains has allowed excessive groundwater pumping to deplete the aquifer to a point where more farmers now face pump lift expenditures that are becoming non-economical. New agricultural practices introduced over the last decades improve irrigation efficiencies, but they still rely strongly on irrigation itself. Pumping of the Ogallala aquifer is estimated to be three times its recharge rate (12). Ninety-five percent of water used from the aquifer is for irrigation (14). The reduced water availability and increased costs of the Southern High Plains cotton production appear to be rendering irrigated cotton production unsustainable.
These heavy-irrigation-dependent systems require little in the way of specific or complex protocols to survive an extended drought. Consequently, it is imperative to develop agricultural alternatives that reduce or virtually eliminate irrigation dependence and to equip those alternate best management practices with robust drought management plans. One possible drought management option is to introduce a forage-based beef production system on the range that combines native rangeland with improved warm-season grasses; and the relevant grasses that fit into this system have been tested on Southern High Plains for over 60 years.
Old World bluestem grasses (Bothriochloa spp.) have been used in the Southern High Plains since the early 1920s (5) and became available for commercial use in the 1930s with the release of the Caucasian Old World bluestems (6). Bell and Caudle (2) reported that approximately 670,000 ha had been seeded with varieties of Old World bluestems in pure stands or in mixtures in regions such as the Rolling Plains, South Plains, and the Panhandle of Texas. Berg et al. (3) noted that approximately 2 million ha had been established in Texas and Oklahoma, 50% of them seeded in the last 10 years (18). Hodges and Bidwell (8) reported that this amount of land seeded with Old World bluestems has great potential for beef production system of the region.
Bothriochloa varieties such as Caucasian, Spar, Plains, and WW-B.Dahl repeatedly show excellent growth and hearty stand maintenance under limited precipitation. WW-B.Dahl, formerly known as WW-857, was originally collected in Manali, India. In 1960 it was brought to the Southern Plains Research Station in Woodward, Oklahoma. After 15 years of adaptation and production trials, WW-857 was selected and finally developed into WW-B.Dahl (2,7). WW-B.Dahl was jointly released in 1994 by the USDA-ARS, USDA-SCS, Texas Tech University, and the Texas Agricultural Experimental Station, and is the most recently released variety of the Old World bluestem species. WW-B.Dah bluestem differs from other commonly used old world bluestems in that it begins stem elongation later in the growing season and produces only one crop of seed (6). WW-B.Dahl remains very green and tends to grow into fall some later than the other bluestems at Ardmore, OK (6).
As a grass for livestock production systems, WW-B.Dahl offers flexibility in beef cattle management when an area has erratic and limited rainfall and includes row crop production processes. Allen et al. (1) suggested that WW-B.Dahl, as a part of an integrated cotton/forage/livestock system, could be maintained profitably with 10.5 inches annual irrigation water when delivered with a subsurface drip irrigation system, providing 140 grazing days per hectare for stockers. In the High Plains, about 5.5 million stocker cattle (about 25% of US total) are shipped to the region each autumn and eventually enter the feed yards. With a strong presence of intensive agriculture along with beef production, it is surprising that there is little integration of livestock and crop production (1) other than the grazing of wheat (Triticum aestivum L.) prior to grain harvest, especially when considering dryland systems that might benefit from the flexibility this integration brings.
Excessive groundwater withdrawal from the Ogallala aquifer has resulted in a lowered water table which obligates producers to extend the depth of their irrigation systems or to adopt alternative irrigation schemes. As a result, irrigated crops become less and less competitive as pumping costs become higher and higher. Implementation of forage/beef production systems could bring some relief to the aquifer and introduce diversification in production agriculture to the region, especially if the appropriate grasses are part of that system. Land-use alternatives to irrigated cotton, especially forage-based alternatives, are emerging as plausible and viable economic operations. Since past research has focused on agricultural practices that extend the economic life of the aquifer, proposed solutions to date have included planting crops that use less water (1,9,15) or implementing forage/beef production systems integrated with crops in a closed system that use less irrigation and non-native range grasses (1,11) with no explicit reliance on rangeland areas. Drought planning may amend that existing model. With the frequent occurrence of drought, the increasing length of drought and the increasing geographical spread of drought, at least recently, this work extends the systems currently under experimental testing to suggest a general approach to drought-readiness adaptations and drought management protocols that could survive a two-year drought without herd loss.
Our goal is to identify reasonable adaptations to current integrated systems by introducing several early drought-readiness practices into day-to-day operations so that a systematic phased plan can be activated quite early in response to signals of possible drought (e.g., very low rainfall in September), with ever-increasing defensive activities as signals persist and worsen. In general, we structure strategic movement of stocker cattle and feeder cattle back and forth between a partially improved range and an integrated livestock and cultivated agricultural system. Given existing experimental data, in particular the recent addition of experimental evidence on the performance of WW-B.-Dahl grass during extremely dry years and uniquely wet years, we propose a baseline drought management protocol with implication for drought-readiness practices that deserve directed study.
Since droughts cannot be experimentally controlled, we suggest a model with modest amendments to regular day-to-day practices to motivate appending to systems that preferably are already under experimental review, to be prepared to empirically test the system under drought conditions when they arise. We think these extensions are modest, so as to not interrupt on-going study and that the model respects the state of data today to locate a reasonable program to complete a sustainable agricultural program for the High Plains. For established cow/calf and stocker systems in the region that use winter and warm-season pastures, warm-season grasses such as bermudagrass [Cynodon dactylon (L.) Pers.] require more water to optimize growth. WW-B.Dahl, can produce forage under limited soil water conditions. Recent research on WW-B.Dahl old world bluestem and cattle performance has evaluated different levels of irrigation, grazing systems, and summer and winter supplementation (4,10,16,17). Additionally, different land-use systems which utilize WW-B.Dahl, ryegrass (Lolium spp.), wheat, sorghum [Sorghum bicolor (L.) Moench], native grasses and a cotton monoculture have been evaluated (1). These studies suggest that the application of limited irrigation water can provide excellent cattle body weight gain per unit area.
This conceptual framework proposes to reduce underground water withdrawal using WW-B.Dahl old world bluestem. The goals are to enhance beef production, increase cattle grazing management options, and sustainability of agricultural activities. The general outcome will be to improve the economic and environmental aspects of existing agricultural operations. The model considers the cow/calf, stocker, and feedlot beef production systems and several alternative cattle transfers among these systems that can be adopted as economic situations and rainfall conditions change. The forage resources available in the Southern High Plains also are considered and are scheduled for use when there is higher forage potential or these areas can be grazed without damaging regrowth of WW-B.Dahl old world bluestem. Forage resources in the Southern High Plains include native rangeland, WW-B.Dahl old world bluestem, and winter wheat (Fig. 1).
The conceptual framework details a flexible forage/beef production system in which transfers from one forage resource to another are depicted. A strong benefit of this added flexibility is to maintain a cattle enterprise even when severe drought conditions persist.
WW-B.Dahl Pasture Management
In early spring (April), fertilization is recommended with ammonia sulfate at 120 lbs/acre. If soil water conditions are not adequate at the time of fertilization, limited irrigation (one inch) is advised. Summer grazing is proposed to begin in June when plants have developed enough leaves to fully support photosynthesis. Grazing is ceased in late October, letting plants complete the reproductive stage to recruit tillers and store carbohydrates. The stocking rate that fits well for this grass for summer cattle grazing is around 600 lbs of live body weight per acre. However, if a dry spring and summer are encountered, the stocking rate should be lowered and irrigation increased. Frequency and amount of water applied (maximum of three inches) will depend on degree of plant wilting and response of the WW-B.Dahl to defoliation. In winter, grazing can begin after the first killing frost has occurred, ensuring that plants have become dormant, thus avoiding harm to the plant growing points. These growing points represent the next season herbage production. Additionally, winter grazing should cease in late winter or early spring as soon as the grass begins to "green-up." Similar stocking rates during the winter could be maintained as in summer, but the cattle will probably need to be supplemented with protein.
Base Cow Herd
The model proposes two options for the cow/calf operation (Fig. 2). First, the base cow herd grazes native rangeland during the winter and spring, and then is moved to WW-B.Dahl pastures to graze all summer and part of the autumn. We suggest designing a breeding program that takes advantage of the high quality summer forage with a stock density that enhances the conception rate. In late October, the cow herd can be returned to native rangeland. The second option is to graze WW-B.Dahl in winter with weaned replacement heifers. Heifers should be supplemented with a high quality protein source during the winter to ensure desirable body condition for the breeding season. During spring move the heifers to native rangeland and bring them back to WW-B.Dahl pasture in summer and early autumn for breeding. After breeding, move the heifers back to native rangeland during autumn. Using this option allows native rangeland to be lightly stocked or rested during summer and early autumn to stockpile forage for potential drought periods and store sufficient carbohydrate reserves in the stem bases and basal crowns for growth next season.
Flexibility is mandatory in stocker operations. Four alternatives can be developed using the forage resources available in the Southern High Plains (Fig. 3). The first alternative starts by grazing weaned steers or heifers from the cow/calf operation on winter wheat. Stockers graze during the winter and spring on wheat pasture and then are moved to WW-B.Dahl in the summer. After 90 days of grazing in WW-B.Dahl, the stockers should be ready to send to the feedlot. In the second alternative, place weaned stockers on WW-B.Dahl during the winter, supplement with protein to maintain or gain weight. During the spring, the stockers can be moved to native rangeland. If winter precipitation is not favorable, then the stockers need to be supplemented. The stockers can graze WW-B.Dahl for three months during summer before going into the feedlot in the autumn. The third alternative proposes that stockers initially graze winter wheat during winter and spring and graze the WW-B.Dahl during the summer and early autumn. They could be finished on native rangeland in late autumn. The last alternative considers keeping weaned stockers on native rangeland during the winter and spring. Stockers should be provided energy and protein supplement to achieve good livestock performance. The stockers can then be moved to WW-B.Dahl for the summer after which they will be sent to the feedlot.
Economic and Environmental Implications
In general, the conceptual model for using alternative grazing schemes on the Southern High Plains relies on the use of forages produced under natural rainfall conditions. The economic outcomes are: (i) reduction in beef production costs due to a reduction in inputs (mainly water and the related energy cost of pumping); (ii) diversification in agriculture to reduce dependence on a cotton monoculture; and (iii) diversification of livestock management options that make use of rangeland to preserve the base herd under recurrent drought conditions.
Managing cropping systems and water use to expand the life of the aquifer has become the objective of many water and producer groups. Integrating cattle management systems into land management programs may be an alternative for farmers to practice water conservation and maintain profitability (1). Contributions of cattle in the system would bring a decrease in water and chemical use with decreased variable costs. Many grass cultivars require less water, fertilizers, and pesticides than crops to generate sustainable production. From an ecological point of view this alternative model proposed will used less water than the conventional cotton system. Therefore, farmers would be able to see the effect of their operation on the environment. They could conserve 12 acre-inches of water per year and reduce nutrient and pesticide loadings.
Results (10) showed that stocker steers grazing on non-irrigated WW-B. Dahl provided higher net returns than those under irrigated WW-B. Dahl pastures during 2003 and 2004, dry and wet years, respectively (Table 1). Further, comparing the net returns from this experiment with stockers in non-irrigated WW-B. Dahl (10) ($124/acre and $90/acre) to the next best enterprises likely to compete for this same land and water, Allen et al. (1) reported net revenues from irrigated cotton in the region of $125/acre for the 1996-2004 period. Sides et al. (13) reported net revenue for monoculture irrigated cotton of $96.09/acre in the absence of current government program payments and $127.27/acre with government assitance. As irrigation costs rise and pumping water requires more energy the close competition of non-irrigated WW-B. Dahl (or limited irrigation of 4 inches) with irrigated cotton in both wet and dry years suggests the system proposed merits further study. If we add the benefits of injecting supporting rangeland into integrated forage/cropping systems, a picture emerges of a sustainable production agriculture land use which meets the increasingly severe droughts in the region without harsh economic disruption. A future study that examines this proof of concept for its economic viability is likely to measure also the extent to which the system conserves groundwater and is less management and labor intensive than some competing alternatives.
Table 1. Net returns per acre ($/acre) in six combinations of irrigation-supplement scenarios in a WW-B. Dahl (Bothriochloa bladhii) pasture grazed by steers in summer in 2003 and 2004 in Lubbock, Texas.
From the environmental point of view, deferment and rest of native pastures improves rangeland health. Late summer and early autumn are crucial for native grasses because they have a high demand for carbohydrates to recruit tillers and accumulate reserves for plant survival and future growth. Therefore, minimizing or avoiding defoliation of these grasses during the post-reproductive to dormant period improves rangeland productivity, and in time, will result in less soil erosion, less water and air pollution, and improved wildlife habitat.
Paper No. T-9-1116, College of Agricultural Sciences and Natural Resources, Texas Tech University.
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