Location: Dairy Forage Research2014 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 application to grazed forage grasses continued in the spring and summer, and potential runoff was measured post-application. Animal management has been modified to account for the increasing variability in nutrient distribution due to grazing. Nitrogen sources were applied to orchardgrass-red clover mixtures, and legume contribution to pasture production was assessed during subsequent grazing events. Objective 2. Dry matter yields and plant density measurements from sites in Wisconsin and Minnesota were completed in the fall of 2013 for a study examining plant spacing effects on the yield of biomass alfalfa. Dry matter yields, plant heights, and plant density measurements are continuing in a collaborative study that is aimed at identifying the optimal rate and time for applying prohexadione-calcium to enhance the survival and subsequent yield of alfalfa interseeded into silage corn. One of two sites in Wisconsin had to be abandoned due excess precipitation in 2013; studies are currently underway at four sites in Wisconsin for 2014. All proposed laboratory work has been completed and published; research has been summarized for technology transfer applications, including a published university extension factsheet. Objective 3. Approximately 125,000 individual red clover plant field observations were taken across multiple nursery sites and harvests. In spring 2014 over 10,000 new red clover space-plants were transplanted and established at eight nursery sites. DNA was extracted from approximately 2,500 red clover plants and 6,500 red clover plants were genotyped for groups of 15 to 20 DNA markers. Objective 4. Progress was made toward completing the analysis of ferulates and lignin and assessing the pretreatment and enzymatic saccharification of maize cell walls artificially lignified with alternate monomers. Crosses were made and new field plots were established for collection of field data on grasses selected for divergent lignin or etherified ferulates. Crosses were also made between European and North American reed canarygrasses for establishment of field experiments to quantify heterosis.
1. A promising bioengineering target for biomass crops is found in epigallocatechin gallate. Plant cell walls are the world’s most abundant source of carbohydrates for fermentation into biofuels. Prior to their fermentation in biofuels, however, these carbohydrates must first be liberated from lignin (indigestible portion of cell wall) by harsh and costly chemical pretreatments. ARS scientists in Madison, Wisconsin are testing ways to modify lignin formation in plants so that it is easier to remove by chemical pretreatments. In this study, they artificially lignified cell walls from corn with normal precursors (i.e. monolignols) plus epigallocatechin gallate, a natural antioxidant found in many plants that is not normally a component of lignin. Incorporation of epigallocatechin gallate into lignin improved the enzymatic release of fermentable sugars from cell walls following a very mild alkaline pretreatment. These results provide compelling evidence that epigallocatechin gallate would be a promising plant genetic engineering target for improving the production of biofuels from biomass crops.
2. Research shows that farmers have choices when selecting companion crop and manure management systems for no-till silage corn. The production of silage corn with companion crops (e.g. cover crops or living mulches) is widely recommended for reducing soil and fertilizer nutrient losses and for maintaining or improving crop yields, nutrient cycling, and soil quality. Manure is a common natural fertilizer for silage corn production. ARS researchers at Madison, Wisconsin evaluated the agronomic and environmental performance of five companion crop systems for corn amended with manure during a four-year study in south central Wisconsin. Overall, researchers found that no companion crop or manure management system was clearly superior in all attributes related to forage production, nitrate leaching potential, runoff, and soil quality. The study will, however, enable producers to better tailor companion crop and manure management practices to meet feed production needs and to enhance the environment by limiting losses of soil and nutrients from cropland.
3. Delaying harvest of Eastern gamagrass improves yield without affecting plant persistence. Eastern gamagrass (a perennial warm-season grass) may be an effective alternative to chopped straw within the blended diets of dairy heifers and cows. Extension materials discussing appropriate fall management of eastern gamagrass often recommend avoiding harvest within six weeks of first frost. However, single-harvest yields of dry matter have not peaked by mid-August in northern climates because of inadequate accumulation of growing degree days. Dry matter yields, plant persistence, and nutritive value were evaluated across four production years for eastern gamagrass harvested at 15-day intervals between August 1 and November 1. Yields of dry matter were increased by 31% on September 15 compared to August 1. Most importantly, there was no evidence that plant persistence was affected negatively by delaying harvest dates. Results of this study will give producers confidence to delay harvests of eastern gamagrass to increase yield because they know that this management practice will not affect plant persistence.
4. Legumes being bred for pasture use should be grown with grasses during selection process. Grazing-based dairy producers often add forage legumes such as birdsfoot trefoil to grass pastures in order to improve the protein content of the feed. For legume breeders looking for improved varieties for pasture use, ARS researchers at Madison, Wisconsin clearly demonstrated that selective breeding of birdsfoot trefoil that is grown in plots with a grass companion, compared to growing alone, produced better varieties for use in pasture situations. This work provides evidence to other forage legume breeding programs, including alfalfa, that forage legume plants being developed for pastures should be selected with a grass companion when possible to increase selection gains.
5. New switchgrass hybrid expands opportunities for growing it as a bioenergy feedstock in northern climates and marginal environments. Switchgrass is one of the leading candidates for bioenergy feedstock production, especially in marginal environments where field crops either are not profitable or are not sustainable. But many of those marginal lands are in the more northern USDA Hardiness Zones 3 and 4 where switchgrass is not as productive as it is in Hardiness Zones 5 and 6. Recent field experiments provided the first demonstration that biomass yields in Zones 3 and 4 can be increased to be similar to those observed in Zones 5 and 6. This was accomplished through directed selection and breeding for high biomass yield and winter survival following harsh winters. The greatest gains in biomass yield, up to a 50% increase, were achieved with hybrid switchgrass that combined high yield of a southern strain with high winter hardiness of a northern strain. This research provides the first documentation of range expansion for high-yielding switchgrass strains into Hardiness Zones 3 and 4.
6. Best methods for improving efficiency and gains in forage breeding programs are determined. Progress toward increased forage yield or biomass yield of perennial plants (such as alfalfa, clover, and grasses) has lagged behind the gains made in annual crops for many years. ARS researchers at Madison, Wisconsin, compared 14 different breeding methods for their theoretical efficiency to improve the rate of gain for forage or biomass yield. The study concluded that significant improvements can be made to nearly all forage breeding programs by using one or more of the following concepts: field-plot trials that simulate real-world conditions, multiple locations for field trials, and/or DNA markers to supplement field-based data. Just a 5% increase in forage yield derived from improving the efficiency of breeding in one major forage crop, alfalfa, would be worth about $30 per acre or $1,560 million across the U.S.
Price, D., Casler, M.D. 2014. Predictive relationships between plant morphological traits and biomass yield in switchgrass. Crop Science. 54:637-645.
Price, D., Casler, M.D. 2014. Inheritance of secondary morphological traits for among-and-within-family selection in upland tetraploid switchgrass. Crop Science. 54:646-653.
Price, D., Casler, M.D. 2014. Divergent selection for secondary traits in upland tetraploid switchgrass and effects on sward biomass yield. BioEnergy Research. 7:329-337.
Grabber, J.H., Jokela, W.E., Lauer, J. 2014. Soil nitrate and forage yields of corn grown with clover or grass companion crops and manure. Agronomy Journal. 106:952-961.
Grabber, J.H., Jokela, W.E. 2013. Off-season groundcover and runoff characteristics of perennial clover and annual grass companion crops for no-till corn fertilized with manure. Journal of Soil and Water Conservation. 68(5):411-418.
Casler, M.D. 2013. Partial decomposition of the genetic correlation between forage yield and fiber using semi-hybrids. Crop Science. 53:1403–1411.
Casler, M.D., Robins, J.G., Coblentz, W.K. 2013. Sparse-flowering orchardgrass is stable across temperate North America. Crop Science. 53:1870–1877.
Casler, M.D., Robins, J.G., Coblentz, W.K. 2014. Sparse-flowering orchardgrass represents an improvement in forage quality during reproductive growth. Crop Science. 54:421-429.
Resende, R., Resende, M., Casler, M.D. 2013. Genomic selection in forage breeding: accuracy and methods. Crop Science. 54:143-156.
Riday, H., Brummer, C.E. 2014. Vigor and persistence of birdsfoot trefoil (Lotus corniculatus L.) populations selected with or without an orchardgrass (Dactylis glomerata L.) companion evaluated in grass sod. Crop Science. DOI:10.2135/cropsci2014.02.0147.
Casler, M.D., Vogel, K.P. 2014. Selection for biomass yield in upland, lowland, and hybrid switchgrass. Crop Science. 54(2):626-636.
Brink, G.E., Digman, M.F., Muck, R.E. 2014. Field drying rate differences among three cool-season grasses. Forage and Grazinglands. DOI: 10.2134/FG-2013-0104-RS.
Vanholme, R., Morreel, K., Darrah, C., Oyarce, P., Grabber, J.H., Ralph, J., Boerjan, W. 2012. Metabolic engineering of novel lignin in biomass crops. New Phytologist. 196:978-1000.
Grabber, J.H., Riday, H., Coblentz, W.K., Cassida, K., Griggs, T., Min, D., MacAdam, J. 2014. Yield, morphological characteristics, and chemical composition of European- and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental United States. Crop Science. 54:1893-1901.
Casler, M.D. 2013. Finding hidden treasure: a 28-year case study for optimizing experimental designs. Communications in Biometry and Crop Science (CBCS). 8(1):23–38.
Resende, R., Casler, M.D., Vilela de Resende, M. 2013. Selection methods in forage breeding: a quantitative appraisal. Crop Science. 53:1925-1936.
Elumalai, S., Tobimatsu, Y., Grabber, J.H., Pan, X., Ralph, J. 2012. Epigallocatechin gallate incorporation into lignin enhances the alkaline delignification and enzymatic saccharification of cell walls. Biomacromolecules. 5(1):1-14.