Final Report for LS08-202
Beginning in 1997, SARE-funded long-term systems research began in the Texas High Plains to conserve water and other natural resources while assuring a level of economic profit to sustain individuals and communities of this region. Initial comparisons of 1) a cotton monoculture and 2) an integrated cotton-forage-stocker steer system demonstrated over 10 years that the integrated approach used about 25% less irrigation water, about 40% less nitrogen fertilizer, was similar in profitability, and increased soil organic carbon, soil microbial activity, reduced soil erosion, and had numerous other benefits compared with the cotton monoculture. With further funding from SARE, a non-irrigated cotton-forage-stocker steer system (3) and a deficient irrigated stocker steer grazing system (4) were added beginning in 2003. After 5 years, a single irrigated forage paddock was added to the non-irrigated system (5) to buffer this system against extreme drought. Finally, beginning in 2009, the original integrated systems were revised to include legumes and all perennial forages with an objective of forage-finishing steers (6) and the monoculture cotton system was converted to monoculture sorghum (7). Stocking rates for the systems varied from 0.23 to 1.6 steers/acre. Irrigation applied annually to each system was 15.6, 11.8, 0, 8.9, 1.7, 6.0, and 7.2 inches for the 7 systems respectively. Total steer gain was 242, 68, 440, 95, and 198 lb/acre for systems 2 through 6, respectively. Gain per acre inch of irrigation water is 20.5, [68 (dryland system; irrigation was zero)], 49.7, 55.9, and 19 lbs for the respective systems. Additional products from some of these systems include hay, grass seed, and cotton. This research is ongoing. Data are being collected to compare systems for their effects on feedlot performance and carcass merit, soil organic carbon, energy balance, greenhouse gas emissions, total productivity, economics, soil quality, nutrient balance, carbon cycling and other measures of sustainability. In 2004, state funding was acquired to implement on-farm producer demonstrations of 30 different systems in two counties including over 4,500 acres. After 5 years, cotton monoculture systems have used more irrigation water than integrated crop/livestock systems. Net returns per system acre have been greater for the integrated systems than the cotton monocultures but reflect changing market prices. Grass seed production produced the most revenue per acre but used more water than other systems. Data from the research and demonstration projects show that systems can be designed to conserve water and energy while maintaining or increasing economic returns.
Our hypothesis is that more energy, water, and soil can be conserved, profitability and sustainability of agriculture can be increased, and the changing priorities and opportunities for agriculture in the semi-arid region of the Texas High Plains can be better addressed through an integrated systems approach than through existing monoculture agricultural systems.
The overall objective is to conserve energy, water, and soil and maintain an agricultural industry that is economically and environmentally sustainable.
Specific objectives are:
- To compare integrated crop and beef cattle (stocker and forage finishing) systems (both irrigated and non-irrigated) and a forage sorghum monoculture for dependence on water (irrigation + precipitation) and energy, and impact on soil quality and erosion, and economic returns.
- To determine energy use, energy efficiency, and energy economics of integrated systems and monocultures, representing both non-irrigated and irrigated agriculture, using both new and long-term replicated field-scale systems and 30 on-farm producer managed systems.
- To translate results from Objectives 1 and 2 into practices incorporated in agriculture in the High Plains and other applicable ecosystems.
The purpose of this project is to conserve energy, soil, and remaining water in the Ogallala aquifer, while enabling agriculture to remain economically and environmentally sustainable in the Texas High Plains. Over the past 100 years, the Texas High Plains grasslands evolved into a $20+ billion agricultural industry centered largely on cotton and finishing beef cattle in feedlots (Fig. 1). Agriculture was made possible with fertile soils, cheap energy and fertilizers, and irrigation water from the Ogallala aquifer. Today, energy and related costs are escalating rapidly, and water in the Ogallala is declining at a rate on average of over 1 foot per year. In areas of where water reserves are greatest, declines of over 10 feet per year are recorded. Recharge is negligible, and water demand exceeds supply. Current trends cannot be continued.
Cropping choices by producers largely follow crop prices and input costs and can lead to excessive water use but limited cropping of strategically irrigated crops and a perennial grass grazing-based beef industry could be sustained indefinitely. To be sustainable, such systems must also be energy efficient and economically viable.
Our SARE-funded research, begun 13 years ago, showed that an irrigated, integrated, cotton-forage-beef stocker cattle system reduced irrigation water (24%) and nitrogen fertilizer (40%) with similar profitability to a cotton monoculture (10-year data). Despite such promising results, both systems continued to demand water in excess of sustainable use. Additional SARE-funded (2002) comparisons of a non-irrigated, integrated cotton-native grass-stocker cattle system and a deficit-irrigated perennial grass-stocker cattle system were included. In 2009, the non-irrigated system was expanded to include one irrigated pasture to buffer this system against drought. Also in 2009, SARE-funding allowed modification of the original two systems to target greater water saving, profitability, and emerging issues. The revised systems include perennial forages for finishing beef cattle and a sorghum monoculture that could flexibly meet needs for grazing, silage, or biofuels.
Because of success of this on-going long-term systems research, state funding was acquired in 2004 to monitor 30 producer sites (over 4,500 acres) that include an array of systems ranging from crop monocultures to crop rotations, integrated crop and livestock systems, and all-forage systems. Examples of both irrigated and non-irrigated systems are included. All systems are monitored for total water use and profitability as well as additional system characteristics.
With this historic and ongoing platform of replicated research and on-farm producer systems, we are generating information on production, plant and animal product quality, profitability, water use, inputs, energy use and energy economics, soil microbial relationships, carbon sequestration, emission of greenhouse gasses and other information so urgently needed to design efficient agricultural systems. New tools are being designed in collaboration with producers to maximize responses while limiting amounts of irrigation water applied.
Objective 1. Systems comparisons: All systems are replicated 3 times in a randomized block design. All irrigated systems and system components were subsurface drip irrigated (Fig. 2) with meters on each individual paddock and replicates of both systems as described by Allen et al. (2005). Angus and Angus cross steers with an initial body weight of about 500 lbs are used in this research. At the end of the grazing seasons, all steers enter the feedlot for finishing on a conventional high-grain diet. Days to finish and feedlot performance are recorded. Following slaughter, carcass characteristics are collected. All studies are conducted under approved Animal Care and Use Protocols.
Systems are compared for system and component water and energy use and efficiencies, plant and animal product quantity and quality, input requirements, economic profitability, and soil conservation and quality. A Farming Systems Research and Extension approach is used to increase awareness, knowledge sharing, and adoption of appropriate technologies within the region and beyond using participatory methods with producers and industry as full partners to establish true Communities of Practice.
All data are subjected to statistical analyses appropriate to specific experimental components and systems comparisons.
1997 through 2008 (11 years). This research was continued through 11 cropping years (10 years with cattle present). For a full description, see Allen et al. (2005).
Crop monoculture. This subsurface drip-irrigated system consisted of a cotton monoculture with conventional cultural practices currently recommended for this region (Fig. 3).
Integrated cotton-forage-livestock system. This 3-paddock system included about 54% of the area established in WW-B. Dahl old world bluestem (Bothriochloa bladhii) with the remaining area equally divided in a 2-paddock alternate rotation of cotton/wheat/and rye (Fig. 4). Following graze-out of rye, cotton was no-till planted into stubble (Fig. 5) and cattle moved to wheat in the alternate paddock. Wheat was no-till planted into cotton following harvest in November while rye was planted into the alternate paddock in September after graze-out of wheat and a summer fallow period. Cattle entered the system in January to graze dormant old world bluestem and rye as available. Following graze-out of wheat, cattle returned to summer graze old world bluestem until mid-July when they entered the feedlot for finishing (Fig. 6).
2003 to present.
Non-irrigated integrated cotton-forage-livestock system (2004 – 2008; 5 years). This 3-paddock system provided grazing on native perennial grasses (sideoats grama, bluegrama, buffalograss, and green sprangletop) from May until about August (Fig. 7). Cotton was grown in annual rotation with foxtail millet (Seteria italic) in the remaining two paddocks. Millet provided additional late summer grazing (Fig. 8). Steers entered a feedlot for finishing at the end of the grazing season. No irrigation was used, either for establishment or for production.
Deficit-irrigated grazing system (2007 to present; ongoing). This 3-paddock, perennial warm-season grass system includes 54% of the total area in WW-B. Dahl old world bluestem with the remaining area equally divided into two paddocks of Tifton 85 bermudagrass (Cynodon dactylon; Fig 9). Grazing is sequenced among the two paddocks of bermudagrass and bluestem until mid-August when grazing is terminated on bluestem. Steers complete the grazing season on bermudagrass and enter a feedlot by mid-October. Excess forage if present is harvested for hay. The bluestem is harvested for seed in October. Irrigation is limited to a maximum of 12 inches annually for bermudagrass and a maximum of 10 inches for old world bluestem.
Buffer-irrigated integrated cotton-forage-livestock system (2009 to present; ongoing). At the end of 5 years of the non-irrigated system, it was concluded that the vulnerability of a system totally dependent on the vagrancies of precipitation could be buffered by inclusion of one paddock with forage that could be irrigated if conditions warranted. Thus, in times of extended drought, the system had options to continue grazing rather than having to ‘sell’ cattle. Thus, each replicate of the non-irrigated system described above was revised to include an adjacent paddock of WW-B. Dahl old world bluestem that had been established at the same time as the original experiment but was used in the interim to graze extra cattle. Thus, these 3 paddocks were experimentally ready for this revision to immediately be implemented. The original paddocks remain non-irrigated and the buffer paddock (approximately 20% of total system) is deficit irrigated to supplement grazing. Steers enter a feedlot for finishing at the end of the grazing season.
2009 to present; ongoing.
Forage-finishing. This 4-paddock system attempts to take weaned medium-framed Angus calves to a finished weight and grade on pasture. During 2008 and 2009, the original 3-paddock integrated crop-livestock system described above (1997-2008) was revised as follows: 1) ‘WW-B. Dahl’ old world bluestem was overseeded with biennial yellow sweetclover and alfalfa; 2) José tall wheatgrass and alfalfa (Fig. 10) and 3) a native grass mixture replaced the cotton/small grain rotations Additionally, with the exception of a caged-non grazed area, the paddock previously used for continuous cotton is included with this system to provide additional grazing of a forage sorghum monoculture. Each of the forage mixtures and the forage sorghum are limit-irrigated but the native-grasses are only irrigated in extreme conditions. Steers are supplemented with DDG’s from the ethanol industry to increase energy and protein beginning mid-summer (Fig. 11). Steers sequence graze the three forage mixtures from May to October when they enter the feedlot for finishing if a finished weight and grade are not accomplished on pasture.
Crop Monoculture; Forage Sorghum for Silage. This non-grazed system, located in a caged area of the former continuous cotton system, is a forage sorghum monoculture harvested for hay or silage that could supply feed to the dairy or feedlot industries. This area remains ungrazed from the beginning of the systems research in 1997. Hairy vetch was seeded as a cover crop prior to sorghum in autumn 2009 and was overseeded into sorghum in autumn 2010. Sorghum was no-till planted into terminated vetch in spring 2010.
All Systems. Inputs of water (amount and distribution of precipitation and irrigation), energy, chemicals, seed, machinery, and labor and other inputs are recorded. Economic profitability, plant and animal productivity, botanical composition, changes in soil quality and fertility, and erosion potential are measured. Soil quality and functioning are being assessed through effects on soil carbon and nitrogen contents, rainfall infiltration, soil aggregation, bulk density, microbial community composition and enzyme mediated reactions of carbon, nitrogen, phosphorus, and sulfur nutrient cycling as described by Acosta-Martinez et al. (2004). Plant nutrients applied are based on annual soil test results using Texas Agricultural Experiment Station recommendations and pesticides on recommendations of Integrated Pest Management Specialists. No nitrogen fertilizer is applied where legumes are included. Soil mineral status is especially of interest for phosphorus and nitrogen when DDGS is supplemented to grazing cattle. This is a significant source of both nutrients and is distributed in manure (P and N) and urine (N) of grazing steers and can substitute in part for fertilizer. Other nutrients are monitored.
Soil microbial relationships, carbon partitioning, and greenhouse gas emissions from these systems are being measured by teams led by Dr. J. Moore-Kucera (Texas Tech University) and Dr. V. Acosta-Martinez (USDA-ARS, Lubbock, TX) and funded by USDA-SARE and NIFA grants.
Yield and quality of harvested crops are determined. Cattle are weighed initially and at mid-season, with a final shrunk weight taken at the end of the grazing season. Forages are sampled at 28-day intervals to establish seasonal growth and to document forage mass and nutritive value. Exclosed areas (4.8 m x 4.8 m) established at the beginning of the experiments exist in all paddocks that include cattle. These exclosures allow studies to determine effects of grazing vs. no grazing and are contributing to several research objectives.
Objective 2. Data from our SARE-funded research described above from the past 10 years are being used as well as data collected from the 30, producer-managed sites in the 2-county Demonstration Project to determine profitability and energy used. Direct, indirect, and total energy inputs are estimated as described by Zilverberg et al. (2011). In addition to the research sites, these producer sites include cotton monocultures, crop rotations with corn, sorghum, and small grains for grain or silages, integrated crop and livestock systems, and all forage/livestock systems. They include irrigated (center pivot, sub-surface drip, and furrow irrigation) and dryland examples. Year 5 of this on-going project was completed in February 2010. Year 6 is being summarized.
Objective 3. Both the research and the producer demonstration sites are used to increase awareness, knowledge, and adoption of appropriate technologies. Education and extension specialists at Texas Tech and within the Texas A&M system collaborate with farmer participants to reach industry, producers, other stakeholders, and the general populace. For more detail, see TAWC (2010).
- Late in day cotton being stripped. Photo by Phil Brown, Texas Tech University
- Cotton no-till planted into grazed out rye protects young plants. Photo by Philip Brown, Texas Tech Univerisy
- Cattle on native grass pasture consisting of blue grama, sideoats grama, and green sprangletop. Photo by Paul Green, Texas Tech University
- Caged area in foxtail millet pasture following grazing. Photo by Paul Green, Texas Tech University.
- Cattle grazing bermudagrass. Photo by Philip Brown, Texas Tech University.
- Cattle grazing alfalfa/Jose tall wheatgrass. Photo by Paul Green, Texas Tech University.
- Installing subsurface drip irrigation tapes.
- Integrating cotton production and cattle grazing proves benefitial. Photo by Philip Brown, Texas Tech University
- Cattle grazing WW-B. Dahl old world bluestem in summer. Photo by Philip Brown, Texas Tech University
- Supplementing steers with dried distillers grain byproduct. Photo by Paul Green, Texas Tech University
- Cutting excess forage (alfalfa/tall wheatgrass) for hay. Photo by Paul Green, Texas Tech University
Continuous cotton vs. an integrated cotton/forage/livestock system. In 2008, we completed 10 years of data collection on the original comparisons of a cotton monoculture and an integrated cotton-forage-stocker cattle system. Results of the first 5 years have been published (Allen et al., 2005; 2007; 2008). Manuscripts covering production (Allen et al., xxxx), energy and carbon (Zilverberg et al., xxxx) and economic aspects (Weinheimer et al., xxxx) are in preparation. Effects of systems on microbial and soil organic carbon have also been published (Acosta-Martinez et al., 2004; 2008; 2010a; 2010b). Briefly, the integrated system used about 25% less irrigation water (11.8 vs. 15.6 inches, respectively) and 40% less nitrogen fertilizer than continuous cotton. Cotton lint yield was similar between the two systems (1217 vs 1215 lb lint/acre, respectively). Both systems were above regional means for irrigated cotton (821 lbs lint/acre, Southern High Plains). The alternative system provided about 180 grazing days with about 65% of the time spent on old world bluestem pastures. Stocking rate was 0.76 steers/acre. Steers gained about 306 lbs (1.7 lb/day) during the time grazing was allowed and were feedlot ready by mid-July. Soil microbial activity and organic carbon were higher in the integrated system paddocks than in continuous cotton by the end of 10 years.
Non-irrigated system. This completely dry-land system produced grazing for stocker steers and cotton. During the first 5 years, the system stocking rate (including land in cotton) was 0.23 steers/acre. Grazing began in May and was generally terminated by August. Averaged over the 5 years, steers gained about 313 lb or about 68 lbs/system acre and cotton yielded approximately 528 lbs/acre. Cotton yield average included 2 years of failed crops. Averaged over the years that produced a harvestable crop, yield averaged 880 lbs/acre. This system was highly vulnerable to weather and precipitation patterns. In 2 years, no cotton was harvested and in 1 year, steers were removed from the system by June.
Deficit irrigated grazing system. The 3-paddock bermudagrass/old world bluestem system required the longest time to become established and research ready. Initial seeding of bluestem paddocks began in 2003 with reseeding required during the next 2 years to ensure adequate stands. Bermudagrass was sprigged after adjacent bluestem paddocks were established to minimize encroachment of bermudagrass into these pastures. During 2005 and 2006, cattle were used to graze these paddocks as establishment was completed and research began in 2007. Data collection on this system continues. Appropriate stocking rate was determined to be 15 steers/system or 1.6 steers per acre. Steers gained 440 lbs/acre in this system with approximately 8.9 inches of irrigation water applied.
Buffer irrigated integrated cotton/livestock system. Beginning in 2009, stocking rates were increased from 0.23 to 0.36 steers/acre with the inclusion of the one irrigated forage paddock into the otherwise non-irrigated system. Averaged over the 2 years completed thus far, total gain/acre increased from 68 to 95 lbs/acre with a mean of 1.7 inches of irrigation water (system basis). Inclusion of the irrigated paddock increased flexibility of managing these sequence-grazed paddocks and improved forage management opportunities. Excess forage in both years was present and stocking rates will be increased in 2011. Non-irrigated cotton produced harvestable yields in both years with a mean of 450 lb/acre.
Forage finishing system. One year has been completed on this revised system and cattle for year 2 will begin grazing in early May, 2011. All pastures are fully established and interseeding of legumes into old world bluestem paddocks was successful. During year 1, stocking rates were lower than anticipated for subsequent years as forages became fully established. Hay was harvested if excess forage growth occurred (Fig. 12). Burning of old world bluestems prior to interseeding legumes reduced growth during 2010 as anticipated. Stocking rates during 2010 were 0.8 steers per acre but will be increased to about 1 steer per acre in 2011. Total gain per acre in 2010 was 198 lbs/acre with a mean of 6 inches irrigation water applied in this system.
The influences of systems on performance during feedlot finishing and on carcass merit are being evaluated. These data are not yet available but are being collected.
Five years of data have been collected from the producer demonstration sites (TAWC, 2010). Producer systems represent 1) monoculture cotton, sunflowers, and perennial grass seed and hay systems; 2) multi-crop systems including cotton in rotation with corn, grain sorghum, wheat for grain, or rye as well as rotations of corn and sunflowers and a sorghum/wheat rotation; 3) integrated crop/livestock systems including both cow/calf and stocker cattle sysems, and 4) a perennial-grass, cow/calf, hay system. Irrigation types include subsurface drip, center pivot, furrow irrigation, and non-irrigated systems. For the irrigated systems, amount of water applied ranged from 3.5 to 23.8 inches on a system basis. Dollars generated ranged from a negative $90 to a positive $597 per system acre. Income ($) generated per inch of irrigation water ranged from a negative $14 to a positive $38 per acre.
Comparisons among system types have shown that more irrigation water was applied to grass seed monocultures than any other system type. In descending order of irrigation amounts, grass seed are followed by cotton grown in monoculture systems, multi-cropping systems, sunflowers, integrated crop/livestock systems, and the cow-calf forage system using the least amount of irrigation water. Net returns per acre inch of irrigation water are highest for the grass seed monoculture systems (Fig. 13). In descending order this is followed by multi-cropping systems, the cow-calf system, integrated crop/livestock systems, cotton monocultures, and finally sunflowers grown in monoculture (less than $2/acre). Net returns per system acre were highest for the grass seed monoculture (about $480/acre; Fig. 14) followed by multi-cropping systems (about $120/acre), integrated crop/livestock systems (about $100/acre), cotton monoculture systems (about $70/acre), cow-calf/forage system (about $60/acre) and sunflowers (about $10/acre).
Energy analyses are ongoing for both the producer sites and the replicated systems. Initial results have been presented by Weinheimer and Johnson (2008; 2010 – see below). Manuscripts are in preparation as the data are developed.
Systems are the integration of all of their parts and system design within these types influences their behavior. Corn, a component of some of the multi-cropping and integrated crop/livestock systems, required more irrigation water than any other system or system component (over 18 inches). Small grains and perennial grasses generally required the least irrigation water.
As new systems are designed, this research and demonstration project is providing the information to create more water use efficient and profitable systems. This information combined with improved technologies for irrigation scheduling and water use efficient genetics is contributing to increased water savings.
Educational & Outreach Activities
Additional means of disseminating information include: Educational materials, websites, radio presentations, media coverage, press releases, workshops and field days.
Selected conference proceedings:
1. Weinheimer, J.A., Johnson, P., and Tom Knight. Economics of State Level Water Conservation Goals. Selected paper presentation Western Agricultural Economics Association, Kauai, Hawaii. July 2009.
2. Weinheimer, J., E. Wheeler-Cook, D. Ethridge, D. Hudson. Macroeconomic Impacts on Water Use in Agriculture. Selected paper presentation, Southern Agricultural and Applied Economics Association: Annual Meeting. Orlando, Florida, February 2010.
3. Weinheimer, J. and P. Johnson. Carbon Footprint: A New Farm Management Consideration in the Southern High Plains. Selected paper presentation, American Agricultural Economics annual meetings. Denver, Colorado. July 2010.
4. Weinheimer, J., N. Rajan, P. Johnson and S. Maas. 2010. Carbon Footprint: A New Farm Management Consideration in the Southern High Plains. Selected Paper 11607. 2010 Meetings of the Agricultural and Applied Economics Association. July 25-27, 2010, Denver, CO.
5. Weinheimer, J., P. Johnson, T. Knight, and E. Segarra. 2009. Economics of State Level Water Conservation Goals. Selected for presentation at the 2009 Meetings of the Western Agricultural Economics Association. June 24-26, 2009, Kanai, HA.
6. Weinheimer, J.A. and P. Johnson. 2010. AEnergy and Carbon: Considerations for High Plains Cotton.@ 2010 Beltwide Cotton Conferences Proceedings, pg. 450-454. Selected for presentation at the 2010 Beltwide Cotton Conference. Co-sponsored by the National Cotton Council and the Cotton Foundation, January 4-7, 2010, New Orleans, LA.
7. Weinheimer, J.A. and P. Johnson. 2008. AEnergy Analysis of Cotton Production on the Southern High Plains of Texas.@ 2008 Beltwide Cotton Conferences Proceedings, pg. 449-453. Selected for presentation at the 2008 Beltwide Cotton Conference. Co-sponsored by the National Cotton Council and the Cotton Foundation, January 8-11, 2008, Nashville, TN.
Peer-reviewed journal papers
1. Acosta-Martinez, V., T. M. Zobeck, and Vivien Allen. 2004. Soil microbial, chemical and physical properties in continuous cotton and integrated crop-livestock systems. Soil Sci. Soc. Am. J. 68:1875-1884.
2. Allen, V. G., C. P. Brown, R. Kellison, E. Segarra, T. Wheeler, P. A. Dotray, J. C. Conkwright, C. J. Green, and V. Acosta-Martinez. 2005. Integrating cotton and beef production to reduce water withdrawal from the Ogallala Aquifer. Agron. J. 97:556-567.
3. Philipp, D., V.G. Allen, R.B. Mitchell, C.P. Brown, and D.B. Wester. 2005. Forage Nutritive Value and Morphology of Three Old World Bluestems Under a Range of Irrigation Levels. Crop Sci. 45:2258-2268.
4. Philipp, D., C.P. Brown, V.G. Allen, and D.B. Wester. 2006. Influence of irrigation on mineral concentrations in three old world bluestem species. Crop Science. 46:2033-2040.
5. Allen, V. G., M. T. Baker, E. Segarra and C. P. Brown. 2007. Integrated crop-livestock systems in irrigated, semiarid and arid environments. Agron. J. 99:346-360. (Invited paper).
6. Philipp, D., V.G. Allen, R.J. Lascano, C.P. Brown, and D.B. Wester. 2007. Production and Water Use Efficiency of Three Old World Bluestems. Crop Sci. 47:787-794.
7. Marsalis, M.A., V.G. Allen, C.P. Brown, and C.J. Green. 2007. Yield and Nutritive Value of Forage Bermudagrasses Grown Using Subsurface Drip Irrigation in the Southern High Plains. Crop Sci. 47:1246-1254.
8. Allen, V. G., C. P. Brown, E. Segarra, C. J. Green, T. A. Wheeler , V. Acosta-Martinez, and T. M. Zobeck.. 2008. In search of sustainable agricultural systems for the Llano Estacado of the U.S. Southern High Plains. Agric. Ecosystems Environ. 124:3-12. (Invited paper)
9. Acosta-Martinez, V., S. Dowd, S. Yung, and V. Allen. 2008. Tag encoded pyrosequencing analysis of bacterial diversity in a single soil type as affected by management and land use. Soil Biology & Biochemistry 40:2762-2770
10. Dudensing, J., J. Johnson, P., and C. Villalobos. 2008. Grazing Alternatives in the Face of Declining Groundwater: A Case from the Southern High Plains of Texas. Texas Journal of Agriculture and Natural Resources. 21:60-72.
11. Maas, S. J., and N. Rajan. 2008. Estimating ground cover of field crops using medium-resolution multispectral satellite imagery. Agronomy Journal 100(2), 320-327.
12. Wheeler-Cook, E., E. Segarra, P. Johnson, J. Johnson and D. Willis. 2008. Water Conservation Policy Evaluation: The Case of the Southern Ogallala Aquifer. Texas Journal of Agriculture and Natural Resources. 21:89-102.
13. Johnson, J., P. Johnson, E. Segarra and D. Willis. 2009. Water Conservation Policy Alternatives for the Ogallala Aquifer in Texas. Water Policy. 11: (2009) 537-552.
14. Rajan, N., and S.J. Maas. 2009. Mapping crop ground cover using airborne multispectral digital imagery. Precision Agriculture Volume 10, No. 4, August 2009. http://www.springerlink.com/content/1385-2256
15. Acosta-Martinez, V., S.E. Dowd, Y. Sun. D. Wester, and V. Allen. 2010. Pyrosequencing analysis for characterization of soil bacterial populations as affected by an integrated livestock-cotton production system. Applied Soil Ecology 45:13-25..
16. Acosta-Martinez, V., G. Burrow, T. M. Zobeck, and V. G. Allen. 2010. Soil microbial communities and function in alternative systems to continuous cotton. SSSAJ 74:1181-1192.
17. Acosta-Martinez, V., et al. 2010. Long-term soil microbial community and enzyme activity responses to an integrated cropping-livestock system in a semi-aird region. Agriculture, Ecosystems and Environment 137:231-240.
18. Maas, S. J., and N. Rajan. 2010. Normalizing and converting image DC data using scatter plot matching. Remote Sensing. 2(7):1644-1661.
19. Rajan, N., S. J. Maas., and J. C. Kathilankal. 2010. Estimating crop water use of cotton in the Texas High Plains. Agron. Journal 102:1641-1651.
20. Zilverberg, C. P. Johnson, J. Weinheimer, and V.G. Allen. 2011. Energy and Carbon Costs of Selected Cow-Calf Systems. Rangeland Ecology and Management (In review).
Manuscripts in progress: more than 12.
Acosta-Martinez, V., T. M. Zobeck, and Vivien Allen. 2004. Soil microbial, chemical and physical properties in continuous cotton and integrated crop-livestock systems. Soil Sci. Soc. Am. J. 68:1875-1884.
Allen, V. G., C. P. Brown, R. Kellison, E. Segarra, T. Wheeler, P. A. Dotray, J. C. Conkwright, C. J. Green, and V. Acosta-Martinez. 2005. Integrating cotton and beef production to reduce water withdrawal from the Ogallala Aquifer. Agron. J. 97:556-567.
TAWC (Texas Alliance for Water Conservation). 2010. An integrated approach to water conservation for agriculture in the Texas southern High Plains. 5th Annual Report to the Texas Water Development Board. Austin TX. http://www.depts.ttu.edu/tawc/resources.html
Zilverberg, C. P. Johnson, J. Weinheimer, and V.G. Allen. 2011. Energy and Carbon Costs of Selected Cow-Calf Systems. Rangeland Ecology and Management (In press).
This overall SARE-funded research made possible the success in state funding received to initiate a long-term producer-led demonstration of 30 different systems on over 4,500 acres in Hale and Floyd Counties. This would not have happened without the research in progress described above and is providing the producer-led, landscape scale, real-time testing of system effects on water use and profitability. A major product emerging from the producer-led team is TAWC-Solutions, an on-line tool (made free to the public www.tawcsolutions.org) to calculate irrigation scheduling, estimate potential profitability and water use by various cropping options, and other information.
The impact of both the research and the demonstration project is growing exponentially with producer participation, adoption, and implementation of water saving strategies. This is an evolutionary process in our long-term program on integrated systems and, thus, it represents a progression of research, education, and implementation (Fig. 15).
Funded by additional SARE grants and additional grants obtained from the USDA-NIFA Proof of Concept funding and other funding sources, research within these systems is providing information on energy balance, greenhouse gas emissions, carbon cycling, soil organic carbon fractions, soil compaction, soil quality, carbon cycling through the grazing animals, shifts in botanical composition within the systems, effects of cover crops on allelopathic effects on the following target crops, potential variation in alfalfa varieties to persist and yield under limited irrigation, effects of different legume species or nitrogen fertilization under limited irrigation on carbon and nitrogen in soils and plants as well as yield and forage quality, and other vital information.
The following are among the products that have come from this effort.
- Graduate students completed; 9 M.S. and 8 Ph.D.
- Graduate students in progress: 3 M.S. and 2 Ph.D.
- Three Post Docs.
- Four visiting scientists.
- Refereed journal publications: 20 published or in press.
- Conference/abstracts/proceedings: 35
- Popular articles: 26
- Workshops: 15
- International talks: 6
- Talks/tours/presentations/seminars: more than 200
- Combined visitors: over 2,500.
The research and demonstration sites have hosted numerous local, regional, state, and national visitors including scientists, policy makers, students, producers, industry representatives, state agencies and others with an interest in the future of agriculture. Additionally, visitors have come from numerous foreign countries including Mexico, France, Australia, Israel, Brazil, Argentina, New Zealand, Russia, Thailand, China, and Africa.
Economic analyses are conducted as described by Allen et al. (2005; 2007a) where prices are held constant to examine system behavior. Additionally, annual economic comparisons are made based on current-year prices for inputs and products. Complete cost analyses of every input and management practice are being made. The overall systems are compared, as well as change over time within systems.
For more detail, see TAWC (2010).
Overall, the data from these experiments demonstrate that systems based on or inclusive of forages and livestock require less water for irrigation and livestock use than systems based entirely on row crops. How the system is configured, the forage species used, and the timing of grazing all impact total water required and economic profitability. The economic analyses are ongoing. Pumping depth influences cost of irrigation. As water declines, the energy required and associated costs increase. Economic comparisons are made for different pumping depths. Data reported here are for a 150-foot depth. Economic data presented here also reflected annual changes in crop and input prices that occurred in this region. Initial comparisons of a cotton monoculture and an integrated cotton/forage/livestock systems showed that during the first 5 years, the integrated system was more profitable than continuous cotton ($206 vs. 141/acre, respectively). With a change of cotton varieties to reflect changes in technology available, the following years improved profitability for cotton. Averaged over the entire 10 year period, there was no difference in profitability between the two systems with both systems showing about $125/acre in profit.
Profitability for the non-irrigated integrated cotton/forage/livestock system over 5 years varied from a negative $359/acre to a positive $73/acre. This system is highly vulnerable to weather and subject to crop failures and to limited forage for grazing. Changing this system to include a single irrigated paddock appears to be improving the profitability potential. Increasing stocking rates to more completely utilize forages now available may improve profitability but the non-irrigated cotton component of this system remains vulnerable. Likewise, the non-irrigated warm-season annual grass in rotation with cotton provides limited grazing and does not appear to justify costs of including this in the system.
The limit-irrigated bermudagrass/old world bluestem system has increased in profitability each year over the 4 years it has been in place. Improvements in grazing management and harvesting excess forage for hay appear to be key differences in profitability but changes in prices also have been reflected. This system began with a negative $122/acre but returned a positive $64/acre in 2010.
The forage-finishing system will require more years of data before meaningful economic analyses can be performed. With only 1 year of data and pastures not yet fully established, there is insufficient information at this point.
Farmer adoption of information, technologies, and management strategies is occurring in response to a multipronged approach but a key aspect of this is producer participation in the process (Fig. 16). With the demonstration project, farmers are central to monitoring the effects of management practices and to implementing water saving approaches on their own farm or ranch. Producers have been primary participants in the design of some of the tools now available to more strategically apply water to crops. Producers are involved in teaching other producers implementation of water-saving strategies.
Additionally, our research has provided information on adaptation of legume species and varieties for this region and inclusion of legumes has been adopted by some producers with interest expressed by more. Based on our results, marginal lands formerly included in cropping systems are increasingly being taken out of production and converted to perennial grasses allowing remaining water to be focused on fewer cropland acres with a potential for hay, grazing, and/or a grass seed crop from the marginal land if precipitation occurs. Sequence grazing of two or more different forage types has been adopted by some producers to extend grazing seasons and to approach year-round grazing. Much interest has been expressed in potential forage species that are productive with limited irrigation. Because of the SARE-funded research and the TAWC demonstration, we have producer-tested experience on which to make recommendations. As is appropriate, producers are adopting components that fit their goals and individual systems.
This research has created a greater awareness of the need for water conservation and has provided a ‘reality check’ on water actually being applied to various crops and systems. Producers are moving toward a more integrated strategy to match water with fertility to target realistic yield goals rather than maximum production. Producers have been involved in developing some of the irrigation scheduling technologies that were producer driven and are being tested on-farm. They have input into what the final product looks like.
With impending water regulation, greater adoption of systems and technologies to optimize use of water and other natural resources will be paramount for this region. This research and demonstration project is providing producer-tested and proven approaches to meeting these challenges.
The educational and outreach efforts of this overall program have been extended through publication examples listed below.
1. Leigh, K., & Doerfert, D. L. (2008). Farm-based water management research shared through a community of practice model. Paper presented at the 44th Annual American Water Resources Association (AWRA) Conference, New Orleans, LA.
2. Wilkinson, J., & Doerfert, D. L. (2008). The critical role of the community coordinator in facilitating an agriculture water management and conservation community of practice. Poster presented at the 44th Annual American Water Resources Association (AWRA) Conference, New Orleans, LA.
3. Newsom, M., Doerfert, D. L., & Carr, J. (2008). An exploratory analysis of the ruralpolitan population and their attitudes toward water management and conservation. Poster presented at the 44th Annual American Water Resources Association (AWRA) Conference, New Orleans, LA.
4. Williams, C., Doerfert, D. L., Baker, M., & Akers, C. (2008). Developing tomorrow’s water researchers today. Poster presented at the 44th Annual American Water Resources Association (AWRA) Conference, New Orleans, LA.
5. Pauley, P.S., Baker, M., Smith, J., Doerfert, D., & Kelly, P. (2007). Political and civic engagement of agriculture producers who operate in selected Idaho and Texas counties dependent on irrigation. Proceeding of the 2007 Universities Council on Water Resources (UCOWR)/National Institutes for Water Resources (NIWR) Annual Conference, Boise, ID.
6. Norton, M., Miller, P., & Doerfert, D. (2006). The value of water: Educational programming to maximize profitability and decrease water consumption. Poster presented at the Southern Region AAAE Conference, Orlando, FL (received Second Place Innovative Idea category award)
7. Couts, M., Chudalla, S., Findley, M., & Doerfert, D. (2006). Conservation outreach communications: A framework for structuring conservation outreach campaigns. Poster presented at the Western Region AAAE Conference, Boise, ID (received Second Place Research category award)
8. Norton, M., Miller, P., & Doerfert, D. (2006). The value of water: Educational programming to maximize profitability and decrease water consumption. Poster presented at the Annual AAAE Conference, Charlotte, NC.
9. Couts, M., Chudalla, S., Findley, M., & Doerfert, D. (2006). Conservation outreach communications: A framework for structuring conservation outreach campaigns. Poster presented at the Annual AAAE Conference, Charlotte, NC.
10. Findley, M., & Doerfert, D. (2007). Considering conservation outreach through the framework of behavioral economics: a review of literature. Poster presented at the AWRA 43rd Annual Water Resources Conference, Albuquerque, NM.
11. Edgar, L., Miller, R., & Doerfert, D. (2007). How do we value water? A multi-state perspective. Poster presented at the AWRA 43rd Annual Water Resources Conference, Albuquerque, NM.
12. Miller, Pamela (2006). West Texas High School Agriscience Teachers’ Knowledge, Confidence, and Attitudes Towards Teaching Water Quantity-Related Topics. Master’s Thesis, Department of Agricultural Education & Communications, Texas Tech University.
13. Carr, Jessica (2007). An Examination of Rural Small Acreage Homeowners in Three West Texas Counties. Master’s Thesis, Department of Agricultural Education & Communications, Texas Tech University.
14. Leigh, Katie (Fall 2008). A Qualitative Investigation of the Factors That Influence Crop Planting and Water Management in West Texas. Master’s Thesis, Department of Agricultural Education & Communications, Texas Tech University.
15. Williams, Claire (Spring 2009). The Effectiveness of Using a Workshop to Change Agriscience Teacher Behaviors Towards Agricultural Water Management Instruction. Master’s Thesis, Department of Agricultural Education & Communications, Texas Tech University.
16. Wilkinson, Jarrott (Summer 2009). The Relationship of Trust And Personality Factors of a Knowledge Source on the Information-Seeking Behaviors of Agriculture Professionals. Master’s Thesis, Department of Agricultural Education & Communications, Texas Tech University.
17. Jones, Heather (Spring 2010). The influence of a professional development workshop on teachers’ intentions to include water management content into their local agriscience curriculum. Master’s Thesis. Department of Agricultural Education & Communications, Texas Tech University
Areas needing additional study
The researchable questions emerging from this long-term system research are virtually endless and increase exponentially with time. That is one of the true values of long-term research sites. In addition to elaborating and expanding research objectives already in progress, new opportunities are emerging.
Up to this point, all of our systems research has used stocker cattle as the grazing animal. As the water in the aquifer continues to decline, there is an increasing interest in cow-calf systems. Research to develop profitable and sustainable cow-calf systems is needed urgently for this region. Likewise, research that includes other grazing animals within the system including both sheep and goats is needed.
As this region moves progressively to more forage use, much more information is needed on potential forage species including both legumes and grasses and forbs that could contribute to designing successful systems. Basic research is needed to explore such opportunities. Furthermore, the impact of inclusion of legumes on soil water within the profile should be examined.
With inclusion of feeding the by-product from the ethanol industry, nutrient cycling through the animal and impact on soil fertility needs to be addressed.
Effects of systems on wildlife habitat have been explored within the producer demonstration sites and this work should be expanded and continued. Irrigation strategies for cropping systems are under intense investigation but studies should address such strategies for forages as well. Grass seed production appears to be a profitable industry for this region but much information is needed to minimize water and nitrogen use to optimize water use with seed yield and economics.
In short, there is an enormous opportunity for addressing researchable questions within this long-term system site. We are greatly indebted to the USDA-SARE program for making this possible.