1999 Annual Report for LS99-100
Systems for sustainability of alfalfa production on acid, Coastal Plain soils using various harvesting strategies
Summary
Texas A&M University scientists at Overton developed technology for successful production of alfalfa on acid Coastal Plain soils. Southern Region Sustainable Agriculture Research and Education Program funding allowed expansion of evaluations and demonstrations of sustainable alfalfa production systems.
Objectives
1.) Development of soil amendment and nutrient management plans to enhance establishment and sustainability of alfalfa on acid, Coastal Plain soils.
2.) Develop multiple-option defoliation strategies using hay, silage, greenchop, and/or grazing to improve stand survival and sustainability of alfalfa.
3.) Develop risk assessment models to project economic benefits from alfalfa production on Coastal Plain soils.
4.) Use a variety of the latest technologies to transfer best management practices to stakeholders in the southern U.S.
Approach
Field studies at Overton, and Nacogdoches, Texas and a greenhouse experiment were established to evaluate the effectiveness of gypsum and flue gas desulfurization by-product for reducing phytotoxic subsoil aluminum levels in strongly acid soils. Field soils were sampled before and several times after treatment. Three harvests of alfalfa were made before a prolonged drought curtailed growth. Six harvests of alfalfa were made from 48-inch-deep pots of soil in the greenhouse. Rooting depth, aluminum, leachate, and leached nutrients will be analyzed in soil samples from sectioned pots. Alfalfa samples have been analyzed for chlorophyll and GDH isoenzyme patterns. Fructose and starch analyses are in progress. Nutrient analyses are planned.
In cooperation with five stakeholders, alfalfa production demonstrations totaling 32 acres were established. Sites located in Gregg, Rusk, Cherokee, Anderson, and Smith Counties were selected and treated with best management practices developed for alfalfa production by TAMU scientists. Yields curtailed by 80+ days of no substantial rainfall ranged from 4 to 5 tons of 12%-moisture hay/acre. All stands survived the prolonged drought. Four educational meetings and tours of stakeholder alfalfa demonstrations, organized by County Agricultural Agents and principal investigators, were hosted by stakeholders and attended by approximately 116 producers. Details and procedures for the alfalfa demonstrations were discussed at a meeting of stakeholders and County Agents. Scientists in the Texas Forage Workers and the Beef Cattle Work Groups toured one stakeholder site, as did several Regents of the TAMU-System.
A replicated study was established at Overton, Texas to evaluate tolerance of Alfagraze, GrazeKing, Amerigraze 401+Z, Hay Grazer, Amerigraze 702, and Cimmaron 31 alfalfa varieties to rotational or continuous grazing by beef cattle. Pre- and post-grazing plant height and physiological development were recorded. Pre-grazing forage samples were collected for nutritive value. This site was visited by field day tour groups and other special tours. Common bermudagrass invasion and alfalfa stand losses were evident for some varieties this third year.
A second replicated study was established at Hope, Arkansas to evaluate beef cattle performance on grazed alfalfa compared to common bermudagrass. Alfalfa provided 237 animal grazing days compared to 406 for common bermudagrass. Total gains of 307 and 328 lb/acre, respectively, did not differ between forage types.
Data collected and summarized after completion of this project will be used, along with data from earlier studies, to generate economic projections and probability estimates for successful production of alfalfa on Coastal Plain soils. Alfalfa is an excellent alternative crop for forage producers on the Coastal Plain.
Multi-county tours will continue in succeeding years of this project. At each field tour, stakeholders hosted and shared their experiences and management expertise with participants. Digital video and slides of production practices are being captured for development of an Internet web site and a video that details the practices essential for successful production of alfalfa on Coastal Plain soils.