Location: Dairy Forage Research
Project Number: 5090-21000-065-000-D
Project Type: In-House Appropriated
Start Date: Dec 5, 2017
End Date: Mar 3, 2019
1: Develop defoliation & N application management guidelines for temperate grass-legume pastures of the NC & NE 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 & 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 next 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 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 & etherified ferulates on ag 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 3 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 for existing & emerging markets, & improve dairy resilience to abiotic/biotic stressors while maintaining economic viability. Use a comprehensive systems approach, along with existing/new databases & models, to identify opportunities & support Livestock GRACEnet, LTAR & Climate Hub efforts to improve environmental performance of dairy systems in the NE, MW & West. 6: Characterize the contribution of cover crops to serve as animal forage, to enhance soil nutrient retention, and to reduce pathogen release from dairy production systems.
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.