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

This project funds the maintenance of the long-term field site at the Texas Tech New Deal Research Farm in support of long-term sustainability objectives. We installed capacitance probes in old world bluestem pasture to assess the practicality of soil moisture monitoring for improving the efficiency of irrigation. The annual grass teff was tested for hay production under dryland and minimal irrigation. A graduate student tested digital image analysis for measuring ground cover and leaf area development in old world bluestem. A nine-year project demonstrating crop water conservation was extended five years with $3.6 million funding from Texas Water Development Board.

Objectives/Performance Targets

The overall objectives of crop-livestock research and demonstration projects at Texas Tech University are to (1) understand the biological, environmental, social, economic, and policy issues impacting agricultural sustainability in the Southern High Plains, and (2) to translate research into adoption of more sustainable practices. The Long-Term SARE grant contributes a critical piece of this effort by funding the maintenance of the long-term field research site at the New Deal Research Farm, which is the basic platform for our collaborative research and education efforts. The research arm of our effort (Texas Coalition for Sustainable Integrated Systems, TeCSIS) focuses on the integration of forage-based beef production into the region’s predominantly row-crop agriculture as a means of reducing water extraction from the Ogallala Aquifer, building soil organic matter, stabilizing soil from wind erosion, and diversifying income. The outreach arm of our effort (Texas Alliance for Water Conservation, TAWC) partners with 20 producers to demonstrate improved irrigation practices on 30 fields near Lubbock, TX. TAWC produces field days, field walks, conferences, radio and TV reports, Twitter and Facebook messages, web-based management tools, and printed fact sheets to reach a diverse rural and urban populace on using practical technologies to sustain agriculture and communities. Research at the New Deal Research Farm is a source of information pertaining to grazing systems that help meet producers’ goals of stretching water supplies and reverting cropland to perennial grasses in ways that meet their economic goals.

We visualize the following trends in Southern High Plains agriculture in the coming decades in the context of transitioning to low-irrigation management: (1) smaller acreages of irrigation of value-added crops, (2) continual improvements in water use efficiency of major row crops such as cotton, (3) partial replacement of irrigated row crops with perennial grasses and legumes and with dryland crops, especially sorghum, (4) greater use of precision water management technologies such as ultra-low and variable-rate irrigation, (5) greater dependence on online decision aides for guiding inputs, and (6) warmer temperatures leading to greater evaporative demand and more droughts. These trends will require constant testing of forage systems across the range of weather conditions experienced to offer options to landowners on how to maintain profitability.

Accomplishments/Milestones

Total precipitation at the New Deal Research Farm in Nov. 2012-Oct. 2013 (our cropping year) was 16.7 inches (long-term normal is 18.5 in.), and April-September precipitation was 10.2 inches. Thus the 2013 growing season afforded some relief from drought; however, the amounts were still below normal and did not compensate for the drought from November 2010 through winter 2013. Recent rainfall from November 2013 through March 2014 has only been 1.0 inches, and the soil profile is essentially depleted of water. We expect 2014 to be another drought year. Normal irrigation levels from April through September for the forages are maintained annually at approximately 12 inches for the alfalfa/tall wheatgrass pastures and 9 inches for the WW-B.Dahl old world bluestem pastures, both with and without legume. The native grass pastures did not ever receive irrigation.

We determined ground cover by species using a grid-frame quadrat in the various pasture mixtures in early December 2013 to characterize recovery and stand condition after the 2011-2012 droughts. No grazing occurred in 2013 to facilitate recovery for the next round of grazing research. Bermudagrass pastures will eliminated by applying glyphosate. The following table summarizes the ground cover data, as the average of two observers and three replications. There were two sets of native grass pastures, established in 2002 and 2008, as indicated.

Pasture type      Species                 % cover

Native 2002      Blue grama              37
                        Sideoats grama       15
                        Buffalograss            13
                        Other                      15
                        Bare ground             20

Native 2008        Blue grama              28
                         Sideoats grama        36
                         Buffalograss              0
                         Other                      15
                         Bare ground             21

WW-BDahl          WW-BDahl                73
                          Other                        1
                          Bare ground             26

BDahl/alfalfa       WW-BDahl                78
                          Alfalfa                       9
                          Bare ground             13

Alfalfa/grass        Alfalfa                      64
                          Tall wheatgrass         15
                          Other                         1
                          Bare ground              20      

The ground cover data indicate that the forage systems comprising introduced species are capable of surviving an intense drought as long as some supplemental irrigation is supplied or if the system consists of native grasses that have adapted to stresses associated with lack of irrigation. Low rainfall periods reduce forage production, but water is conserved while enabling the grasses to survive a drought of this magnitude. Initial observations and evaluation are positive; however, the lingering effects of such a drought could take several years to understand its full impact on production, persistence, the soil and producer attitudes and management decisions for the future.

Other activities in the 2013 reporting year included the first year of a Master’s thesis on the use of a digital camera to record overhead images of WW-BDahl grass throughout its growing season. The objective was to determine whether a free, image analysis software (ImageJ) could process the photos to distinguish between live, green leaf area and background dead and bare areas, calculate live cover area, and establish relationships between those values and leaf area index and forage yield. Results indicate that image analysis provided rapid ground cover data, and that positive predictive relationships to leaf area and forage yield were obtained. This technique will allow quick analysis of vegetative cover in pastures and afford its possible use in developing predictive models of WW-BDahl growth and water use.

We compared two brands of capacitance probes (John Deere Field Connect® and AquaSpy®) for monitoring changes in soil moisture in a BDahl pasture irrigated with subsurface drip. Retrofitting an established perennial grass pasture with these probes offers the challenge of correct placement in relation to the drip-lines and emitters to obtain proper readings, a process that is much easier in row crops because soil digging allows exact placement. The data from the capacitance meters provided reasonably good tracking of soil moisture. We will continue our evaluation of these probes in 2014.

We harvested hay in 2013 because no grazing was done. Yields averaged 1340 lbs/acre for alfalfa/tall wheatgrass, 3600 lbs/acre for WW-BDahl old world bluestem, 1320 lbs/acre for teff, and 7740 lbs/acre for sorghum-sudangrass. We also harvested 9.7 lbs/acre of WW-BDahl seed (pure live seed basis). No hay or seed was harvested from the native mixtures. We observed that the annual grass teff established easily, provided one good hay cutting under dryland and two under irrigation, and provided a residual stubble that afforded excellent soil protection from wind. We will use teff in the next round of grazing trials to determine its carrying capacity in response to water supply.

Preparations were made to establish a one-acre area of small plots that will contain a sprinkler irrigation system. The aim is to evaluate alfalfa varieties for drought tolerance. We’ve observed in our pasture work in recent years that alfalfa has an untapped potential as a useful legume in the High Plains under limited irrigation. It has persisted well in mixture with tall wheatgrass. The 9% average cover shown in the table above understates the alfalfa composition because the December readings were done when crowns showed no regrowth in late fall. We also plan to assess alfalfa as a protein bank for limited access by cattle. The design would involve allowing cattle access for 4 hours/day, for 3 days/week. We will initiate that grazing trial in 2014.

Impacts and Contributions/Outcomes

Over the entire history of this project since an initial SARE grant in 1997, the amount of information and student education, thesis, field days, instructional videos, handouts, presentations, and journal articles has been enormous and indicates the potential return on investment in long-term research and education. Below we present the 2013 output of publications by the research team, feature articles in nationally distributed magazines, major presentations, and major grant proposals submitted.

The outreach effort in the TAWC project has been very successful in reaching farmers and disseminating information on best practices for managing irrigation. The result of this success was that we obtained additional $3.6 million from the Texas Water Development Board to continue TAWC for five more growing seasons (2014-2019). This is an example of how the support of research infrastructure at the Texas Tech New Deal Research Farm has been leveraged to amplify the transfer of sustainable agricultural technology in the Southern High Plains.

New graduate students in Plant and Soil Science and Agricultural Economics have been recruited to conduct research on the pastures designed to extend the online decision aides in TAWC for irrigation scheduling and the allocation of forage crops to fields to optimize the economics of water use.

Numerous presentations were made by TeCSIS and TAWC personnel to local commodity groups, producers, researchers, and elementary schools. Long-term research on soil biology at the New Deal Research Farm (led by Jennifer Moore-Kucera) was written up in a feature article in Crop, Soil and Agronomy News. This is the formal news magazine of the Tri-Societies of Agronomy, Crops and Soils. This magazine has wide readership nationally and internationally. The long-term grazing work of TeCSIS and water conservation work of TAWC was written up in a Crops and Soils, a magazine also published by the Tri-Societies and aimed at crop consultants and industry personnel. These articles attest to the wide interest and timeliness of the SARE-supported maintenance of the Texas Tech New Deal Research Farm.

Through SARE support for this systems research we will continue to seek ways to conserve, cooperate, educate and strive to continue to solve the ever pressing issues of sustainability and the challenges to agriculture today.

Journal articles published:

Davinic, M., J. Moore-Kucera, V. Acosta-Martínez, J. Zak, V.G. Allen. 2013. Soil fungal distribution and functionality as affected by grazing and vegetation components of integrated crop-livestock agroecosystems. Applied Soil Ecology 66:61-70.

Fultz, L.M., J. Moore-Kuceraa, T.M. Zobeck, V. Acosta-Martínez, D.B. Wester, and V.G. Allen. 2013. Organic carbon dynamics and soil stability in five semiarid agroecosystems. Agriculture, Ecosystems and Environment 181:231-240.

Fultz, L.M., J. Moore-Kuceraa, T.M. Zobeck, V. Acosta-Martínez, and V.G. Allen. 2013. Aggregate carbon pools after 13 years of integrated crop-livestock management in semiarid soils. Soil Science Society of America Journal 77:1659-1666. 

Johnson, P., Zilverberg, C.J., V.G. Allen, J. Weinheimer, P. Brown, R. Kellison, and E. Segarra. 2103. Integrating cotton and beef production in the Texas Southern High Plains: III. An economic evaluation. Agronomy Journal 105:929-937.

Li, Y., V.G. Allen, F. Hou, J. Chen, and C.P. Brown. 2013. Li, Y., V.G. Allen, F. Hou, J. Chen, and C.P. Brown. 2013. Steers grazing a rye cover crop influence growth of rye and no-till cotton. Agronomy Journal 105:1571–1580.

Li, Y., V.G. Allen, J. Chen, F. Hou, C.P. Brown, and P. Green. 2013. Allelopathic influence of a wheat or rye cover crop on growth and yield of no-till cotton. Agronomy Journal 105:1581–1587.

International, national, and regional presentations:

Brown, C. Philip, V.G. Allen, R. Kellison, P. Green, C.J. Zilverberg, P.N. Johnson, V. Acosta-Martinez, and C.P. West. 2013. Integrating beef and cotton production reduces irrigation needs in the Texas Southern High Plains. Proc. 22nd Int. Grassl. Congr., 15-19 September, Syndey, Australia.

Kellison, R., V.G. Allen, C.P. Brown, D.L. Doerfert, P.N. Johnson, S.J. Maas, and C.P. West. 2013. Using forages to conserve water in semi-arid irrigated cropping systems. Proc. 22nd Int. Grassl. Congr., 15-19 September, Syndey, Australia.

Rocateli, A.C., C.P. West, M.P. Popp, K.R. Brye, and J.R. Kiniry. 2013. Simulating seasonal trends in switchgrass biomass using Almanac. In Annual meetings abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.

West, C.P., C.P. Brown, and V.G. Allen. 2013. Integrated crop/forage/livestock systems for the Texas High Plains. 67th Southern Pasture and Forage Crop Improvement Conference. 22-24 Apr., 2013, Tyler, Texas.

Xiong, Y., C.P. West, and C.P. Brown. 2013. Digital image analysis of Old World bluestem canopy cover and leaf area. In Annual meetings abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.

Feature articles on our project:

Ehmke, Tanner. 2013. More crop per drop: Integrating crops, livestock and new water saving technology. Sept-Oct 2013:6-12 Crops and Soils. American Society of Agronomy.

Fisher, Madeline. 2013. Tiny indicators of change. Microbes in the Texas High Plains may lead to better understanding of how changes in production, environment affect soil health. Crop Soil Agronomy News. August 2013:4-10. doi:10.2134/csa2013-58-8-1.

Proposals submitted:

West, C., S. Trojan, C. Meyers, J. Moore-Kucera, and P. Johnson. Transitioning Texas High Plains agriculture toward low water use with integrated pastures and livestock. Southern-SARE Research and Education. Not funded.

West, C., R. Kellison. 2013. Texas Alliance for Water Conservation-Phase II. Texas Water Development Board. Funded.

Collaborators: