2010 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.
The studies on the effects of accelerated aging on Italian ryegrass seed germination and seedling growth have been completed. The studies on water uptake during imbibitions and germination of Italian ryegrass and tall fescue are in progress; based on these results tolerance of the grass to desiccation during germination will be determined. Effects of hydration-dehydration as compared to accelerated aging have been delayed. Instead the preferential predation of selected grass forages seeds has been completed. Cricket predation appears to be based on seed size; smaller seeds have higher predation rates than larger seed. Small plot field experiments that examined the effects of reduced input sowing methods on forage production of cool-season grasses over-seeded in unimproved warm-season pasture were completed and a report prepared for publication. An experiment to evaluate the productivity and persistence of summer-dormant and summer-active tall fescue varieties carried out in collaboration with ARS staff at the Dale Bumpers Small Farms Research Center continued in FY 2010. An experiment to examine the effect of application timing on efficiency of nitrogen fertilizer use by cool-season grass was started in FY2010. Study of the effect of low-temperature exposure on leaf appearance in annual ryegrass was continued during the reporting period, but adverse weather during winter of 2009-10 caused failure of experimental planting and no plant growth data was collected in FY2010.
Relative productivity of ryegrass and tall fescue cultivars is unchanged by soil compaction. The potential for savings in energy cost associated with conventional tillage, and reduction in risk of soil erosion, has created significant interest in use of no-till methods for sowing forage grasses. No-till sowing is usually made into soils that are more compacted than conventionally cultivated seedbeds and concern has been expressed that variety performance may differ between no-till and tilled conditions. Scientists of the Grazinglands Research Laboratory, based at Langston, Oklahoma, demonstrated that increased soil compaction generally slowed seedling growth and development. However, the relative productivity of a range of commercially available cultivars of Italian ryegrass and tall fescue forage grasses was unchanged by increased compaction of soil. The work suggests that cultivar productivity rankings determined under conventional cultivation and sowing are likely to be valid if the same cultivars are established in more-compacted soils that are characteristic of no-till sowing conditions. Therefore evaluation of grass cultivar performance specifically for no-till conditions should not be necessary.
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 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 continued one on-farm demonstration project with over-seeded annual ryegrass and made presentations on cool-season forage production in two meetings and one field day with limited-resource producers.
Bartholomew, P.W., Williams, R.D. 2010. Overseeding unimproved warm-season pasture with cool- and warm-season legumes to enhance forage productivity. Journal of Sustainable Agriculture. 34:125-140.