Long-term AgroEcosystems Research and Adoption in the Texas Southern High Plains - Phase I

Long-term AgroEcosystems Research and Adoption in the Texas Southern High Plains - Phase I

Summary

The year 2011 broke all previously existing records for drought in the Texas High Plains. From Nov. 2010 through Oct. 2011, the nearby Lubbock airport received approximately 4 inches (107 mm) precipitation, the lowest Nov. through Oct. rainfall since recordkeeping began in 1911 (NOAA, 2011). In spite of this drought, the research (TeCSIS) and demonstration (TAWC) programs continued and have produced valuable and unique information in regard to how these systems function under extreme stress. These research and demonstration projects and their ongoing objectives are:

TeCSIS Replicated Research: In 2011, established with a previous SARE grant, forage-finishing cattle supplemented with distiller’s by-product from the ethanol industry was to continue but allocation of cattle has been delayed. Days to finish, carcass merit, and profitability will be compared with two on-going grazing systems for stocker steers with conventional feedlot finishing. Carbon and nitrogen intake and excretion by grazing steers will be estimated. Soil microbial research will be expanded to include mycorrhizal fungal relationships. Greenhouse gas emission research, including nitrous oxide, methane, and carbon dioxide, continues. The role of legumes vs. nitrogen fertilizer in carbon and nitrogen cycling continues. Management of warm-season grasses to optimize seed production with minimum nitrogen and water is being investigated.

TAWC Producer Demonstration: During initial years, systems were monitored to develop baseline data to determine variation among these producer-driven systems. Much has been and will continue to be learned from these sites. In 2010, an implementation phase began with three additional sites. Here, producers agreed to adopt changes in their systems to incorporate more water-saving strategies including irrigation scheduling technologies, choices of crops or varieties, or system design. The number of sites in this implementation phase will be increased to include additional cropping and livestock systems and new technologies. Use of satellite imagery to measure crop water use is being expanded to include forage water use. Strategies to increase adoption of water conservation practices will be expanded by producers but have been dramatically impacted by the 2011 drought.

• Dust storm at Texas Tech Agricultural Research Farm in 2011

Objectives/Performance Targets

Our overall objective is to understand the biological, environmental, social, economic, and policy issues impacting agricultural sustainability in this irrigation-dependent, semi-arid region. Our further objective is to transform knowledge gained into adoption of sustainable practices, to extend appropriate knowledge to other ecosystems, and to educate students to become global leaders. Fourteen years ago (1997), with an initial grant from the USDA-SARE program, we began replicated, irrigated, field-scale systems research. We hypothesized that an integrated cotton/forage/livestock system would be economically viable, require less water, and would enhance other environmental services compared with a typical cotton monoculture (Allen et al., 2005; Acosta-Martinez et al., 2004; 2010). By 2003, a non-irrigated, integrated, cotton/native grass/stocker cattle system and an irrigated all perennial grass stocker cattle system were added. In 2004, a producer-led, on-farm demonstration of 30 different agricultural systems across two counties began to evaluate water use, irrigation management, and economic viability (TAWC, 2010). Irrigation ranges from none to subsurface drip, center pivot sprinkler, and furrow systems. Producers make all decisions but resulting effects on production, water use, and profitability are measured. Within the replicated research (TeCSIS) and demonstration (TAWC) sites, data are collected on production, total water use, crop water use, economics, energy, carbon sequestration, soil microbes, greenhouse gas emissions, and other measures of sustainability. Decision-making and problem-solving behaviors of producers are facilitated to help agriculture adjust to changing regional, U.S., and global needs. Lessons learned here have regional, national, and global impact and application.

• Cattle grazing bermudagrass in normal year
• Cotton crop ready for harvest in normal rainfall and irrigation year

Accomplishments/Milestones

Due to the extreme drought, for the first time, no cattle could be placed on experiment in the TeCSIS replicated systems. Quantity and quality of forages available for grazing could not meet animal demands. Amount of irrigation water that would have been required to attempt to grow for forages would have exceeded both the pumping capacity of wells and the appropriate use of this diminishing water resource had pumping been possilbe. Dry land pastures remained dormant thoughout the season. Pastures being established for inclusion of legumes appeared to survive but with little to no growth.
Producers in the TAWC project managed their systems and water resources while dealing with the multiple objectives of appropriate water use and economic survival. A full report on TAWC sites is available (Texas Alliance for Water Conservation. 2012. An integrated approach to water conservation for agriculture in the Texas southern High Plains. 7th Annual Report to the Texas Water Development Board. Austin TX.)
Within this year of exteme drought, research continued and is providing valuable informaton regarding the impact of drought on agricultural systems and the people of the region. 2011, was the third year of evaluating an integrated cotton/native/grass/beef steer dryland system that was buffered with a single irrigated paddock of an introduced grass with an irrigated bermudagrass/old world bluetem grazing system grazed by beef steers. This was year 5 for the bermudagrass system and included 5 years of evaluation of the non-buffered dryland system. Data are published in the Ph.D. dissertation of Dr. Cody Zilverberg as well as papers that are now in review for publication in journals.

Three manuscripts were published in journals in 2011. They are as follows:

1. Zilverberg, C. J., P. Johnson, J. Weinheimer, and V. G. Allen. 2011. Energy and Carbon Costs of Selected Cow-Calf Systems. Rangeland Ecology and Management. Rangeland Ecology & Management 64(6):573-584.

2. Davinic, M., L.M. Fultz, V. Acosta-Martinez, F.J. Calderón, S.B. Cox, S.E. Dowd, V.G. Allen, J.C. Zak, J. Moore-Kucera. 2011. Pyrosequencing and mid-infrared spectroscopy reveal distinct aggregate stratification of soil bacterial communities and organic matter composition. Soil Biology and Biochemistry 46:63-72.

3. Zobeck, T.M., V.G. Allen, J.J. Cox, and D. Philipp. 2011. Variation of soil and plant characteristics among old world bluestem species. Agricultural Sciences 2:347-356

• Severe drought resulted in wind erosion and build up in native grass area
• With irrigation live vegetation could be maintained but little growth
• Drought impact on dryland cotton
• Lack of rainfall and no irrigation caused grasses to go dormant

Impacts and Contributions/Outcomes

Information continues to flow from the two components of our overall program. Perhaps one of the greatest impacts is information being gathered and analyzed regarding the impact of the 2011 drought on both research and producer-managed systems. With anticipated climate change impacts, not only here but nationally and globally, we are in a unique position to learn and to assemble informaiton that can be extended to other regions regarding the impact of drought and the managment of water and other resource under these extreme circumstances.

Impacts and contributions include publications in journals, completion of graduate students who will have increasing impact on these research and implementation objectives, and a long list of direct impacts through producer meetings, media informaiton, impact on public knowledge and perceptions, and many other outlets for information transfer.

• Presentation of information at site
• Educating producers at a previous field day

Collaborators: