This project funds the maintenance of the long-term field site at the Texas Tech New Deal Research Station in support of long-term sustainability objectives pertaining to the integration of forages and livestock into a predominant row-crop region. Doctoral research finished on 1) survey of ground-active and canopy-foraging insects (including pollinators) as affected by different pastures species and mixtures, and 2) the impact of winter cover crops and tillage on water response of a summer grass (teff). Doctoral research in the field continued on 1) growth analysis and model development of Old World bluestem (OWB) ‘WW-B.Dahl’, 2) analysis of soil microbial communities in pastures, and 3) introduction of alfalfa into dryland native pastures. Data were analyzed from the trials on cover crops, insect surveys, and soil microbes, and manuscripts were prepared for publication. Two Master’s students conducted intensive sampling of soil for biological soil health indicators and of the soil physical properties to better understand the biological and physical limits of these soils under limited water supply. In preparation for a new grazing trial to begin in 2018, alfalfa planted in 2016 progressed without grazing in 2017 to favor establishment after interseeding into a 13-year-old stand of OWB. No cattle were grazed in 2017 for this reason, but the pastured were readied by conducting properly timed hay harvests, irrigations and weed control, and by repairing irrigation leaks. Visits to the site by producers, students, and other professionals were conducted during the year. We continued to integrate our efforts with the Texas Alliance for Water Conservation to broaden the impact of grassland water use efficiency by consulting with producers on options for converting land from irrigated cultivated row crops to perennial forages as an option to reduce reliance on the Ogallala Aquifer.
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 Large-Systems 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 Station, 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 20-30 producers to demonstrate improved irrigation practices on 30-34 fields near Lubbock, TX. TAWC produces field days, field walks, conferences, radio and TV reports, Twitter and Facebook messages, e-newsletters, and web-based management tools to reach a diverse rural and urban populace on using practical technologies to sustain agriculture and communities. Research at the New Deal Research Station 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) fewer acres of irrigation overall and increased acres of limited-acreage high-value crops, (2) continual improvements in water use efficiency of major row crops such as cotton and corn, (3) partial replacement of irrigated row crops with perennial grasses and legumes, water-efficient sorghum and millet crops at low irrigation, and with dryland crops, (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.
We finished a 2-year trial on cover crops initiated by Lisa Baxter, which was funded by a SSARE Graduate Student grant program (GS15-152) titled “Evaluation of winter annual cover crops under multiple residue management: Impacts on land management, soil water depletion, and cash crop productivity.” The winter cover crops rye, wheat, burr medic, hairy vetch, and rape-kale were planted in October of 2015 and 2016, in no-till and conventional-tilled plots, irrigated and nonirrigated in winter. The summer crop was teff in 2016 and 2017.
In Year 1, the greatest cumulative yields were observed in rape-kale (irrigation or dryland) and irrigated rye, follow by dryland rye. The remaining cover crops produced negligible yields. In Year 2, the greatest cumulative yields were produced by irrigated rye, followed by irrigated hairy vetch and dryland rye, then wheat (both irrigation regimes) and dryland hairy vetch. The burr medic and rape-kale stands failed in Year 2. Hairy vetch performed much greater in Year 2, increasing total seasonal yield from 40 to 660 lbs/acre, which may indicate a high level of dormant seed planted in Year 1.
Hairy vetch (only harvested at second harvest) had the greatest CP concentration. Crude protein was greater in Harvest 1 than Harvest 2 for both small grains, but the decline was greater in rye. Rye averaged 15% in the early-spring harvest and 10% in the late-spring harvest. Nodulation of the two legumes was greater for vetch than burr medic, but tillage tended to reduce vetch nodulation.
In Year 1, competition from rape-kale decreased cumulative summer yields of teff compared to the other cover crops (P < 0.01). Only the winter tillage regime impacted the teff cumulative yield in Year 2 (P < 0.01). This was most likely a consequence of greater water loss in the minimally tilled plots in the top foot of soil. Winter irrigation treatment did not affect teff yield in either year.
The overall result was that Texas High Plains producers should plant rye as a cover crop. Dryland rye produced modest yield (~1,000 lbs/acre), even in a dry year, but light irrigation (2.5 in.), where available, should be used to ensure adequate forage yield (1,200 lbs/acre) if winter grazing is desired. No-till management and timely termination of the winter cover crop were crucial to reduce the impact of winter crops on summer teff (cv. Tiffany) production. Results indicate no detriment to spring soil water content attributable to planting cover crops compared with the conventional practice of winter fallow. Therefore, producers could take advantage of the soil-conserving attributes of cover crops without significant soil water depletion. Results were submitted for publication in Crop, Forage, and Turf Management journal in December, and we are still awaiting word of acceptance.
Among ground-dwelling insects, 47 families among 10 insect orders and 5 families of 5 non-insect arthropod orders were collected. Red imported fire ants and harvester ants were the most abundant insect families. Both types of ants are undesirable in pastures. The significant finding was that pastures that contain Old World bluestem contained virtually none of these injurious ants, indicating a strong benefit from the presence of this grass. The fire ants and harvester ants were most abundant in the native-grass pastures, and intermediate in the alfalfa-tall wheatgrass pastures. Results were published in the journal Crop, Forage, and Turf Management in April 2018.
Related research showed that canopy-foraging insects and insect pollinator numbers tended to be reduced in Old World bluestem relative to alfalfa and native mixed grass pastures, but not enough to indicate that the bluestem would be substantially deleterious to beneficial insect populations. Results were submitted for publication in the journals Agricultural and Environmental Letters and Crop Science, and were accepted in 2018.
Analysis of soils for microbial communities showed that mixtures of bluestem with alfalfa supported the highest levels of soil organic carbon and nitrogen, and the greatest total numbers of soil microbes, whereas these values were least in the native mixed grass pastures. Enzymes associated with transformations of carbon, nitrogen, sulfur, and phosphorus (these plant-essential elements form parts of organically stored compounds) were most active in bluestem-alfalfa pastures. This indicates that the desirable deterrence trait of old world bluestem again fire ants and harvester ants fortunately does not carry over to a negative effect on indicators of soil health. These results contributes to the mounting evidence of WW-B.Dahl old world bluestem as a sustainable perennial grass for the water-limited Texas High Plains. Results from the microbial study were submitted to the journal Applied Microbial Ecology.
Progress so far in the trial of adding alfalfa to the native grass mix shows that alfalfa can survive without irrigation with these grasses. It was encouraging to note that the widely spaced plantings of alfalfa (28-inch spacing) caused only mild depletion of soil water compared to the non-alfalfa (pure grass) control; whereas the narrowly spaced planting (14 inch) significantly reduced soil water content, indicating excessive competition against the grass for soil water. This trial continues in 2018 (a drier year).
The grazing and related forage research at the Texas Tech New Deal Field Research Station is a Large Systems project for which Southern SARE supports the maintenance and routines supplies for conducting integrated forage-livestock research. We superimpose educational activities on the pasture facilities which include visits by farmers and ranchers, foreign visitors, TTU classes in forage and livestock production, and training of graduate students. In 2017 we hosted 26 agricultural students and instructors from the University of Queensland, Australia, who were touring several universities. These students were here on a course for credit for which they had to write term papers. For that reason, they were highly motivated to ask questions on the management of water, nutrient cycling, greenhouse gases, and other factors related to grassland sustainability. Dr. West’s two classes titled Forage and Pasture Crops, and Forages and Livestock Pasture Ecosystems met at the pastures for instructions on plant identification and grazing management. Two of Dr. West’s graduate students and one graduate student each of Dr. L. Slaughter and Dr. S. Deb conducted research on the same pastures pertaining soil health and water relations. Finally, summaries of the the research and demonstration results are included in electronic newsletters that are distributed to 500 subscribers who follow the outreach activities of the Texas Alliance for Water Conservation.
Educational & Outreach Activities
Co-investigator of a 6-state USDA-NIFA funded project on irrigation efficiency to which I bring in integrated crop-livestock aspects.
Directing undergraduate and graduate students in applied research on grassland soil health and cover crops.
Publication with graduate students of 5 refereed journal articles on research conducted on the pastures.
Research summaries in the e-newsletter of Texas Alliance for Water Conservation (TAWC).
Farm tours and grazing demonstrations for classes from Texas Tech University and other universities.
Presentations or co-authorships for 7 water conservation conference and 1 grassland conference on the role of forage-livestock systems in conserving irrigation water and adapting to climate change.
Senior authorship of a chapter in a widely used textbook on forages titled ‘Grassland ecosystems and their management.”
Advising one undergraduate student on a Southern SARE Young Scholar Enhancement Grant on cover crops.
The same types of activities are planned for 2018-2020.
Co-conducted a webinar on improving efficiency of water use in agriculture, as part of the Climate Learning Network/ANREP Community Science Initiative.
Significant interest in how to transition from monoculture cropping to diversified crop-forage-livestock systems as a means of coping with the reduction of the Ogallala Aquifer.
Conversion of formerly irrigated row cropland to perennial grasses for grazing
Improving dryland forage yield and quality by interseeding alfalfa into grasslands
Management of reduced irrigation use on forages
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. The research output and education events at the New Deal research farm tie into broad-scale efforts to disseminate scientifically tested advances in water use, soil management, and integration of crops and livestock in an environment where the main driver of farm profitability and rural economy has been the Ogallala Aquifer, now in decline. These broader efforts include the TAWC, which directly impacts landowners and decision-makers, commercial companies dealing with crop consulting, irrigation equipment, and improved cultivars, collaboration with other institutions with complementary missions such as USDA-NRCS, and finally the greater mission of Texas Tech University in educating students and visitors on land and water sustainability. These efforts demonstrate that the support of research infrastructure at the Texas Tech New Deal Research Station has been leveraged to amplify the transfer of sustainable agricultural technology in the Southern High Plains.
In the 2016 annual report, the significant finding was reported that a 3-year grazing trial analyzed by Lisa Baxter showed greater stocker steer liveweight gains when grazing a pasture rotation system that contained alfalfa compared to grazing grass only, and that the grass-legume system resulted in a lower water footprint for beef liveweight gain; all this with only 7-8 inches (average) of irrigation. These results were published in the journal Crop Science. Dr. West has reported this finding in several invited talks at producer field days and scientific meetings, plus this exposure is attracting national attention. A new grazing trial was initiated in 2018 to follow up with more detailed measurements of the legume effect on water use and cattle production on bluestem-only and bluestem-alfalfa pastures. Also, a new professor in Animal Science (Dr. Darren Henry) joined the team to intensify the measurements of forage intake and enteric methane production by cattle. A soil microbial ecologist (Dr. Lindsey Slaughter) has also joined the team to measure soil emissions of greenhouse gases. We will be able to integrate more thoroughly the aspects of water, nitrogen, and carbon cycling at the soil, plant and animal levels.
Rye is the best option as a winter cover crop in the Texas High Plains because of it tolerance to low water supply and cold temperatures.
WW-B.Dahl old world bluestem is the best perennial grass forage to grazing by beef cattle because of its low water needs, persistence, deterrence of harmful insects (e.g. fire ants), tolerance to continuous grazing, flexibility in use for grazing, stockpiling, and hay, and its good nutritional quality. Plus, it is compatible with alfalfa in mixture.
Alfalfa is the most productive and reliable legume to use in forage systems in the Texas High Plains thanks to it extremely high nutritional quality, persistence with moderate to low irrigation input, compatibility with old world bluestem, and deep roots to extracting water.