Location: Forage and Livestock Production Research2009 Annual Report
1a. Objectives (from AD-416)
The overall goal of this project is to identify improved forage production techniques that will contribute to decreased costs of livestock production and increased income on limited-resource farms. The purpose is to develop low-input forage production techniques that are appropriate for resource-poor producers, and that will increase livestock carrying-capacity, improve early- and late-season forage production and reduce or eliminate expenditures for off-farm feed supplies. This purpose will be met by evaluating combinations of forages grown in mixtures or sequences, and by developing low-input management methods that will enable their use as a productive and persistent complement to, or replacement for, unimproved or degraded pasture. Specifically, we will focus on the following objectives: Objective 1. Identify appropriate forage species and develop low-input techniques for increasing forage production and extending the grazing season on degraded or unimproved pastures to increase year-round availability of homegrown forage and provide economically and environmentally sustainable forage production systems for under-served, resource-limited livestock producers. • Sub-objective 1A. Assess the productivity and persistence of non-traditional warm- and cool-season grass and legume mixtures for utilization under grazing. • Sub-objective 1B. Identify the most effective low-input establishment techniques (no-till drilling, broadcasting or self-seeding) for cool- and warm-season grass and legume forages established in mixtures with existing, unimproved pastures of native species or bermudagrass. Objective 2. Determine the cause(s) of poor establishment of cool-season grasses and legumes following self-seeding or over seeding into established pastures, such as loss of seed quality, hydration/dehydration cycles, temperature or moisture stress, and adverse soil characteristics such as compaction or plant litter. Objective 3. Determine the usefulness of accumulated temperature (degree days) as an aid to timing of pasture management operations such as fertilizer application and harvesting, in order to minimize competition in cool- and warm-season grass mixtures during seasonal transitions.
1b. Approach (from AD-416)
Replicated experiments will be undertaken in controlled-environment or in small-plot field trials to measure management effects on establishment, production and persistence of cool-season forages grown in mixtures with warm-season pasture. Processes of regeneration and persistence in cool-season grasses and legumes established by minimal tillage in sequence with unimproved warm-season pasture will be studied. Low-input methods of sowing that will improve the efficacy and predictability of establishment of forage grasses and legumes and that allow improved early-season production from cool-season forages will be evaluated. Indicators of the onset and termination of forage growth will be determined to facilitate management and to minimize or eliminate interference between cool- and warm-season forages. Results from the project will identify forage management systems adapted to low-input farms and forage mixtures that enhance and extend the productive grazing period of pastures.
3. Progress Report
Field and laboratory studies of predation on forage seeds continued into the current reporting period. Experiments were undertaken to measure the effects of seed age on germination and seedling growth, to understand better the factors affecting survival of self-sown ryegrass In the field. Using artificially aged seed (subjecting seed to high temperature and humidity), we showed that aging reduced and delayed ryegrass seed germination, decreased germination under water stress conditions, and reduced seedling growth and vigor. This translates to reduced likelihood of germination under slight water stress conditions in the field and to reduced competitiveness with other grasses and weeds. Small plot field experiments to examine the effects of reduced input sowing methods on forage production of cool-season grasses overseeded in unimproved warm-season pasture were repeated in FY 2009. An experiment to evaluate the productivity and persistence of summer-dormant and summer-active tall fescue varieties was initiated, in collaboration with ARS staff at the Dale Bumpers Small Farms Research Center. Experiments to evaluate the effects of soil bulk density (soil compaction) on seedling growth in a range of cultivars of annual ryegrass and tall fescue were completed and a report was prepared for publication. Study of the effect of low-temperature exposure on leaf appearance in annual ryegrass was continued during the reporting period.
1. Re-establishment of annual ryegrass by self-seeding: Each year livestock producers throughout the Southern Plains have to overcome problems of shortage of feed for their stock during the cool months of October through March. Grazed cool-season pasture is likely to provide the least costly method of winter feeding, but cool-season perennial pasture grasses do not persist well in the Southern Plains. Italian ryegrass is an annual cool-season pasture grass that is productive in the Southern Plains and may regenerate itself from year to year by self-seeding, without the need for cultivation and sowing. In field studies over four years, scientists from the Forage and Livestock Production Research Unit at El Reno, OK, found that although ryegrass could reseed itself for up to 2 years after initial sowing, the amount of seed needed for establishment of a productive crop varied widely from year to year. Scientists estimated that in just over 40% of cases a self-seeded crop would fail to establish and concluded that over time any cost savings with self-seeding are likely to be offset by its unreliability. In concurrent studies of reduced-input methods of planting, scientists found that ryegrass can be satisfactorily established by broadcast sowing methods that minimize time and equipment needs. Scientists conclude that for resource-limited farmers annual planting of ryegrass will prove more productive and more reliable than re-establishment by self-seeding.
5. Significant Activities that Support Special Target Populations
This research project is specifically directed at the problems encountered by resource-limited farmers and livestock producers and therefore supports the special target population of small, socially disadvantaged, and underserved producers. ARS Grazinglands Research Laboratory (GRL) scientists based at Langston University work closely with the staff of the Langston University Small Farmers' Outreach Center. ARS scientists attend the quarterly staff meetings of the Grasslands Center of Excellence, interact with the outreach specialists, and serve as technical advisors as appropriate. During the reporting period, ARS scientists conducted one on-farm demonstration project with overseeded annual ryegrass, made presentations on cool-season forage production in two meetings and one field day with target farmers, and interacted with numerous small to medium size producers participating in the Farming with Grass Conference.
Williams, R.D., Bartholomew, P.W. 2009. Effects of accelerated aging and p-coumaric on crimson clover (Trifolium incarnatium L.) seed germination.Allelopathy Journal. 23(1):269-276.