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 premise of our research revolves around conserving water through systems that can reduce water use with limited levels of supplemental irrigation. For any such system to be viable these systems must perform under the semi-arid conditions of the area along with the year to year precipitation extremes and distribution patterns encountered. With the record drought of 2011 the TeCSIS (Texas Coalition for Sustainable Integrated Systems) Research Program began the 2012 production year with virtually no soil moisture reserves, receiving only 4.2 inches (107 mm) of precipitation for all of 2011. The average annual rainfall for this area is 18.5 inches (470 mm). This historic drought resulted in crops being abandoned, a reduction in irrigated acres, and shortages of grass and available feed for livestock, resulting in massive reductions in animal numbers on pastures and a major economic blow to the area and state of Texas.

While total precipitation received for 2012 was significantly better than 2011 with a total of 14 inches (364 mm), only 2.7 inches (70 mm) of precipitation was received between January and May at the experimental site and the forecast projection for 2012 was only slightly better than 2011. In addition, the extent of drought damage to the pastures could not be determined until green-up began in spring and as a result, cattle were kept off of the severely drought stricken area to allow the pastures to recover and a more extensive evaluation made.

• Drip irrigation can conserve water
• Dormant Bermudagrass field with OWB fields in background
• Wind blown sand buildup on fence lines of research area

Objectives/Performance Targets

Normal irrigation levels from April through September for the forage crops are maintained annually at approximately 12 inches (305 mm) for the Alfalfa/Jose and Bermudagrass pastures and 9 inches (230 mm) for the OWB (WW B.Dahl old world bluestem) pastures. While 100 percent of these irrigation levels were maintained on the forage-finish pastures in Phase 3, the Phase 2 forage systems only achieved approximately 65% of normal due to mechanical failure of the irrigation system from July through August. The timing and uncertainty of this irrigation system repair and the potential harm to the grass resulted in no hay harvest being made on the OWB pastures on Phase 2. However, 4 inches (106 mm) of precipitation was received in June, which helped mitigate the potential damage during this time period. The Bermudagrass pastures, which do not normally green up until early June, received nearly 4 inches (102 mm) of irrigation in May and June along with approximately 5 inches (130 mm) of precipitation and were harvested for hay on 21 June, producing 0.85 ton acre-1 (1.9 Mg ha-1). No further hay harvests were made in 2012 because of the duration of the Phase 2 irrigation system failure.

Phase 3 hay harvest of the Alfalfa/Jose pastures were also made on 21 June producing 0.71 Ton acre-1 (1.6 Mg ha-1) on the same amount of precipitation and irrigation applied to the Bermudagrass previously specified. Additionally, the OWB/legume pastures were harvested on 19 July and produced 0.85 Ton acre-1 (1.9 Mg ha-1) receiving approximately 6 inches (150 mm) of April-July precipitation and 3 inches (75 mm) of irrigation. A late season attempt to produce grass seed for harvest was made utilizing approximately 3 inches (75 mm) supplemental irrigation and 4.5 inches (113 mm) of precipitation in August and September but an early October 8 freeze, (one day after the earliest first freeze over a 90 year record, Lubbock, TX, NOAA, 2013) destroyed the seed crop before maturity and harvest could be made. However, as a result of the water received all forages were in excellent vegetative condition entering winter for both Phase 2 and Phase 3 forage systems.

• In another dry year every little bit of hay helps
• Round bales harvested from forages

Accomplishments/Milestones

Maximum forage yield and quality was not an objective of the irrigation and forage management strategy imposed on these systems. The intent was to achieve some level of production while allowing the pastures to recover from the worst drought in the history of the area. Through the study of the grass response and recovery, we find that these forage systems are capable of surviving an intense drought as long as some supplemental irrigation can be supplied, or if the system consists of native vegetation of the area that has naturally developed to these stresses over time. Production is limited, but water can still be conserved while enabling the grass to survive a drought of this magnitude. Initial observations and evaluation is positive; however, the lingering effects of such a drought could take several years to understand the full impact of the drought of 2011 on production, persistence, the soil, and producer attitudes and management decisions for the future.

In addition, 8 manuscripts covering various aspects of this research were accepted and subsequently published or are now accepted for publication during 2012. They are as follows:

1. Allen, V.G., C.P. Brown, R. Kellison, P. Green, C.J. Zilverberg, P. Johnson, J. Weinheimer, T. Wheeler, E. Segarra, V. Acosta-Martinez, T. M. Zobeck, and J. C. Conkwright. 2012. Integrating cotton and beef production in the Texas Southern High Plains. I. Water use and measures of productivity. Agron. J.104: 1625-1642.

2. Zilverberg, C.J., V.G. Allen, C.P. Brown, P. Green, P. Johnson, and J. Weinheimer. 2012. Integrating cotton and beef production in the Texas Southern High Plains. II. Fossil fuel use. Agron. J. 104: 1643-1651.

3. Song Cui, V.G. Allen, C.P. Brown, and D.B. Wester. 2013. Growth and Nutritive Value of Three Old World Bluestems and Three Legumes in the Semiarid Texas High Plains. Crop Sci. 53:1-12.

4. Johnson, P., J. Zilverberg, V.G. Allen, J. Weinheimer, C. P. Brown, R. Kellison, and E. Segarra. 2013. Integrating Cotton and Beef Production in the Texas Southern High Plains: III. An Economic Evaluation. Agron. J. (In press).

5. Cody, Zilverberg, Cody J., C. Philip Brown, Paul Green, Michael L. Galyean, and Vivien G. Allen. 2013. Three Integrated Crop-Livestock Systems in the Texas High Plains: Productivity and Water Use. Agron. J. (Accepted with revisions).

6. Li, Yue, F. Hou, J. Chen, C. P. Brown, and V. G. Allen. 2013. Long-term Grazing of a Rye Cover Crop by Steers Influences Growth of Rye and No-till Cotton. Agron. J. (Accepted with revision).

7. Li, Yue, J. Chen, F. Hou, C. P. Brown, P. Green and V. G. Allen. 2013. Allelopathic Influence of a Wheat or Rye Cover Crop on Growth and Yield of No-till Cotton. Agron. J. (Accepted with revision).

8. Fultz, L.M.*, Moore-Kucera, J., Zobek, T.M., Acosta-Martínez, V. and Allen, V.G. 2013. Soil aggregate-carbon pools after 13 years under a semi-arid integrated crop-livestock agroecosystem. Soil Science Society of America Journal. Accepted with revisions on 3/6/2013.

• Native vegetation can capture good rainfall and survive drought through natural adaptation
• Old World bluestem legume mixture. What will survive?
• Old World bluestem in a normal year

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, theses, 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. Through the opportunity awarded by the USDA-SARE program and cooperation with our partners, we gratefully and proudly present a compilation of some of the effort resulting from the continuation of our program. The attached supporting document represents a portion of the output from this investment which we will continue to update with each successive annual report.

Through your 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.

• Clipping quadrats in alfalfa field
• Graduate students taking field measurements of bulk density
• International visitors to our site
• Explaining what we have learned
• Impacts and contributions as a direct result of our SARE funded research

Collaborators: