Location: Dairy Forage Research2016 Annual Report
1: Develop appropriate defoliation (grazing & harvested) & nitrogen (N) application management guidelines for temperate grass-legume pastures of the North Central & Northeastern USA to improve seasonal yield distribution, extend the grazing season, & improve the efficiency & utilization of energy inputs. 1A. Determine influence of manure source & application time on temperate grass productivity, seasonal yield, nutritive value, & persistence, pasture composition, & soil chemical & physical properties. 1B. Determine the influence of N source, N application date & rate, & defoliation management on the productivity & persistence of red clover grown with orchardgrass. 2: Improve establishment, harvest management, & storage methods to reduce N inputs, increase the profitability of crop rotations, increase the recovery of dry matter & nonstructural carbohydrates, improve the energy density of baled hays, & mitigate the negative effects of rainfall on ensiling, storage, & feeding characteristics of rain-damaged silages. 2A. Identify optimal plant spacing to maximize yield of biomass alfalfa. 2B. Develop improved methods for interseeding alfalfa into maize to bring alfalfa into full production the following year. 2C. For large hay packages, quantify effects of several baling factors on subsequent preservation performance of stored hay. 3: Improve pasture grass & legume production systems through increases in establishment capacity, persistence, productivity, resilience to climate extremes, & quality. 3A. Measure comparative effectiveness of mass selection, maternal half-sib selection, & marker-assisted paternal half-sib selection for persistence & biomass yield in diploid red clover. 3B. Determine optimal plant-selection age to simultaneously maximize genetic gain for persistence & biomass yield of red clover. 4: Improve profitability, conversion efficiency, & adaptability to climatic variation in forage & bioenergy crops. 4A. Quantify effect of decreased lignin & decreased etherified ferulates on agricultural fitness of three temperate pasture species, including tolerances to drought, heat, & grazing. 4B. Use a biomimetic model based on artificial lignification of plant cell walls to identify new lignin bioengineering targets for improving fermentability of forage & biomass crops. 4C. Create & evaluate a series of upland x lowland switchgrass hybrids of differing origins to determine if heterosis is related to geographic origin of parents. 4D. Quantify genetic gains made during three cycles of phenotypic selection for increased biomass yield in WS4U upland switchgrass. 4E. Identify spaced-plant traits predictive of sward-plot biomass yield of switchgrass. 5: Improve dairy industry production capacity & environmental sustainability to meet the demands of existing & emerging markets & improve dairy industry resilience to abiotic & biotic stressors while maintaining producer economic viability. Using a comprehensive, systems approach along with existing/new databases & models to identify opportunities & support Livestock GRACEnet, LTAR & Climate Hub efforts to improve the environmental performance of dairy systems across the Northeast, Midwest, & West.
Objective 1. Solid and liquid manure applications will be evaluated in a series of grazing experiments designed to improve seasonal availability of nutrients and seasonal distribution of pasture productivity. Defoliation and manure application treatments will be applied to grass-clover mixtures to identify combinations that increase the competitiveness of red clover in mixed grazed swards. Objective 2. High vs. low-density plant spacing will be evaluated to determine the effect on biomass yield for high-biomass alfalfa cultivars. Gibberellin-based growth regulator treatments will be evaluated for their effect on establishment and seeding-year biomass yield for alfalfa interseeded into maize. Propionic acid preservatives will be evaluated to determine their effect on reducing spontaneous heating and nutrient loss of large-rectangular bales of alfalfa hay. Objective 3. The comparative effectiveness of mass selection, half-sib selection, and marker-assisted half-sib selection will be determined in an empirical study designed to improve persistence and forage yield of red clover. The optimal age for selection of red clover plants will be identified by evaluating empirical gains from selection for persistence and forage yield on selection nurseries of various ages and degrees of plant mortality. Objective 4. The effect of lignin and etherified ferulates on persistence and forage yield will be evaluated in a series of field experiments designed to evaluate progeny with high or low levels of each cell-wall component in three grass species. The direct effects of monolignol substitutes on cell-wall fermentability and saccharification will be evaluated by using these novel compounds, compared to classical monolignols, as substrates for artificial lignification of maize primary cell walls. Heterosis between upland and lowland switchgrass ecotypes will be evaluated in a series of experiments to quantify hybrid vigor and to identify sources of variation that contribute to variation in hybrid vigor. Objective 5. Experimental research will a) determine the effect of pasture stocking density and relative sward maturity on carbon and nitrogen sequestration in mixed grass-legume and grass monoculture pastures; b) test the regional application of a new alfalfa forage and cover crop system for improving alfalfa-corn rotations; and c) evaluate tannin-containing germplasm to promote forage production and feeding systems that enhance the utilization of nitrogen on dairy farms. These data plus data from other objectives will aid in development and validation of whole-farm and pasture models of dairy production being developed by ARS at University Park, PA. The models will be used to guide future research and develop a knowledge base that will assist farmers with carbon and nitrogen management.
Objective 1. Solid and liquid manure were applied in the spring and summer and grazing continued. Manure effects on plant diversity and productivity have become more apparent, underscoring the importance of long-term studies involving animal manures. Nitrogen sources were applied to orchardgrass – red clover mixtures and legume contribution to pasture production was assessed during subsequent grazing events. Objective 2. Yield, morphology, chemical composition, and digestibility data for leaf and stem samples were compiled for a study of biomass alfalfa planted at low to high plant density by conventional row seeding vs. precision-spaced seeding. Due to equipment/software issues, samples must be rescanned to predict chemical composition and digestibility. Objective 2. Collaborative studies were conducted in 2015 to evaluate adjuvants for increasing the effectiveness of prohexadione action on interseeded alfalfa, assess herbicides for use with conventional (non-GMO) corn and interseeded alfalfa, and to identify the most suitable alfalfa varieties for interseeding into corn. In 2016, follow-up studies were initiated to further evaluate herbicide management and alfalfa varieties for interseeding. A new study started in 2016 will identify optimal planting dates for corn and interseeded alfalfa and corn harvest dates to maximize corn yields while ensuring good establishment of alfalfa. Another new study will assess soil nitrogen availability during the growing season for corn interseeded with alfalfa in preparation for future work to optimize nitrogen management for this production system. Objective 2. A series of experiments were completed evaluating the use of propionic-acid-based preservatives on the storage characteristics and nutritive value of alfalfa hay packaged in large-square and large-round bales; acid-preservation of these hays was far more effective when bales were produced in large-square packages. Recently, work on preservation of alfalfa has been expanded to include round-bale silages. Current experiments are evaluating oxygen-limiting barriers within silage plastics, time delays before wrapping, number of plastic layers, and length of storage before feeding in an effort to improve silage fermentation and limit storage losses. Objective 3 - Red clover phenotypic data and genotypic data were collected. These data will be used to answer the hypothesis of objectives 3A and 3B. Field trials to evaluate forage yield and other fitness traits were successfully established. Biomass harvests were also successfully completed on all field studies of switchgrass hybrids.
1. Wrapping silage bales within 24 hours of harvesting improves forage quality and economic sustainability. Many small or mid-sized dairy farms prefer to produce round silage bales for alfalfa storage and feeding instead of dry hay. However, research is needed on improved procedures for wrapping silage bales with enhanced feed quality. ARS researchers at Marshfield, Wisconsin, found that: 1) a prototype bale wrap with an oxygen-limiting barrier did not improve feed quality of bales compared to the same commercially available wrap without the barrier; 2) the energy content of baled silage decreased by about 5% as the time between harvest and wrapping increased from 4 hours to 3 days; and 3) internal bale temperatures were elevated when wrapping was delayed, resulting in poorer feed quality of the silages. This information will encourage forage growers to wrap silage bales within 24 hours of harvesting and therefore produce better quality silage that is more economically sustainable.
2. Fall oats improve sustainability of dairy production. Dairy producers in the north-central U.S. often need stored forages to maintain livestock through the winter. Fall-grown oat is an excellent candidate because it has good yield potential as a late-season crop, provides an opportunity during summer to spread manure, and aggressively uses nitrogen in the soil to help reduce loss to the environment. Fall oats can also be used for managed grazing. However, research is needed to determine soil fertility requirements and management for oats as stored feed, and to determine grazing management for optimum cow performance. ARS researchers at Marshfield, Wisconsin, found that using nitrogen fertilizers increased oat yields for stored feed by 50% or more, that dairy manure applied in summer provided adequate nitrogen, and that oats aggressively take up nitrogen in soil. It was further determined that, for heifers in central Wisconsin, grazing of oats established in August should begin in late September; delaying grazing until mid-October consistently decreased heifer growth, particularly if rapidly maturing oat types were used. This improved fall-oat management information provides dairy producers with additional options to produce quality animal feed, stored or grazed; and to reduce the environmental risk of nitrogen leaching to groundwater.
Presentations were made at small-farm pasture walks, state and regional grazing conferences, and the Midwest Organic and Sustainable Education Service annual conference describing principles of successful pasture management.
Casler, M.D., Vogel, K.P., Harrison, M.L. 2015. Switchgrass germplasm resources. Crop Science. 55:2463-2478.
Evans, J., Crisovan, E., Vaillancourt, B., Schmutz, J., Kaeppler, S., Casler, M.D., Buell, R. 2015. Diversity and population structure of northern switchgrass as revealed though exome capture sequencing. PLoS One. 84:800-815.
Grabber, J.H. 2016. Prohexadione-calcium improves stand density and yield of alfalfa interseeded into silage corn. Agronomy Journal. 108:726-735.
Casler, M.D., Cherney, J., Brummer, E., Dien, B.S. 2015. Designing selection criteria for reed canarygrass as a bioenergy feedstock. Crop Science. 55:2130-2137.
Casler, M.D., Brink, G.E. 2015. Registration of 'Hidden Valley' meadow fescue. Journal of Plant Registrations. 9:294-298.
Riday, H., Smith, M.A., Peel, M. 2015. A simple model for pollen-parent fecundity distributions in bee-pollinated forage legume polycrosses. Journal of Theoretical and Applied Genetics. 128:1865–1879.
Coblentz, W.K., Bertram, M.G. 2011. Effects of a propionic acid-based preservative on storage characteristics, nutritive value, and energy content for alfalfa hays packaged in large, round bales. Journal of Dairy Science. 95:340-352.
Coblentz, W.K., Coffey, K.P., Chow, E.A. 2016. Storage characteristics, nutritive value, and fermentation characteristics of alfalfa packaged in large-round bales and wrapped in stretch film after extended time delays. Journal of Dairy Science. 99:3497-3511.