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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Research Project #424141

Research Project: Redesigning Forage Genetics, Management, and Harvesting for Efficiency, Profit, and Sustainability in Dairy and Bioenergy Production Systems

Location: Dairy Forage Research

2017 Annual Report

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.

Progress Report
Field experiments to evaluate candidate varieties of upland, lowland, and hybrid switchgrass were completed. Initial data analyses has indicated significant gains for biomass yield, due partly to delayed flowering time and greater utilization of the full growing season and to increased cold tolerance of some candidate varieties. Plant and manure sample and data collection and analysis of pasture experiments were completed; manuscript related to clover response to N source is in preparation. Analysis of red clover DNA marker data collected so far has been analyzed. Additional field data is being collected from the field trials during the 2017 growing season to augment data sets. First manuscripts based on data analysis will be submitted for publication during winter 2017/2018. 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 methods. A preliminary analysis of the data suggests planting method and plant density had only minor effects on the yield and chemical composition of biomass alfalfa. A completed collaborative project conducted from 2012 to 2015 with the University of Wisconsin-Madison found that a single application of 0.5 to 1.0 kg a.i. ha-1 of prohexadione-calcium applied on 15 to 25 cm tall seedlings proved most effective for improving stand density and yield of glyphosate-resistant alfalfa interseeded into corn. Ongoing collaborative studies were conducted in 2017 with the corn-interseeded alfalfa system to 1) evaluate herbicides for use in conventional (non-GMO) production systems, 2) identify alfalfa varieties best adapted for interseeding, 3) determine optimal planting dates for alfalfa and planting dates, populations, and harvest dates for corn, 4) refine nitrogen fertilization rates and application methods for corn, and 5) assess impacts of interseeded alfalfa on runoff of soil and nutrients from cropland.

1. Useful DNA markers for switchgrass breeding identified. ARS researchers in Madison, Wisconsin have identified and mapped several potentially valuable DNA markers to the switchgrass reference genome. These markers are located within key genes in the flowering and lignin pathways and have been linked to critical variation in flowering time and lignin concentration of switchgrass biomass – two crucial traits for increasing the biomass potential of switchgrass. These DNA markers can be easily evaluated and scored on large numbers of individuals in a switchgrass breeding program, allowing switchgrass breeders to evaluate plants for flowering time and lignin concentration without conducting field or laboratory evaluations. These results will aid switchgrass breeders in creating more efficient breeding strategies to speed the rate of development of biomass-type switchgrass varieties, resulting in more rapid delivery of high-yielding cultivars to biomass producers.

2. Research leads to major change in manure management on pasture legumes. Legumes such as red clover and alfalfa play a critical role in improving pasture quality, and they can increase livestock performance 25 to 50% compared to pastures consisting of only grasses. ARS researchers at Madison, Wisconsin discovered that spreading manure on pastures, a typical practice, reduces forage legume productivity and pasture quality; and the fertilizer value of the manure does not increase pasture productivity as commonly believed. These findings were consistent regardless of manure type or time of application, and were due to the death of clover plants after application. By maintaining the legume component of pastures, producers have the best opportunity to maximize animal production and minimize costs.

3. More accurate mating models will accelerate gains in forage legume breeding programs. Modeling forage legume seed fertility allows forage legume breeders to better manage inbreeding in their breeding programs. ARS researchers at Madison, Wisconsin created a more accurate model for forage legume seed fertility distribution and showed that the shape of this fertility distribution was linked with environmental stress during seed production. This new model will allow forage breeding programs to accelerate gains for biomass yield, an important trait to improve.

4. Modified lignin derivatives to improve utilization of biomass and forage crops. Plant cell walls in crops are potentially an abundant source of carbohydrates for ruminant livestock and biofuel production, but their utilization is restricted because they are enmeshed in a vital structural component known as lignin. ARS researchers at Madison, Wisconsn are testing ways to modify lignin formation in plants to improve cell wall carbohydrate digestion. In this study, they artificially lignified cell walls from corn with normal precursors plus a wide variety of phenolic compounds that are naturally produced by plants, but not normal components of lignin. The modified lignins improved the ruminal and enzymatic digestibility of cell wall carbohydrates by up to 30% compared to conventional lignin formed with normal precursors. These results suggest some of these derivatives would be promising genetic engineering targets for modifying lignin in forage and biomass crops.

Review Publications
Karlen, S.D., Zhang, C., Peck, M.L., Smith, R.A., Padmakshan, D., Helmich, K.E., Free, H.A., Lee, S., Smith, B.G., Lu, F., Sedbrook, J.C., Sibout, R., Grabber, J.H., Runge, T.M., Mysore, K.S., Harris, P.J., Bartley, L.E., Ralph, J. 2016. Monolignol ferulate conjugates are naturally incorporated into plant lignins. Science Advances. doi: 10.1126/sciadv.1600393.
Broderick, G.A., Grabber, J.H., Muck, R.E., Hymes-Fecht, U.C. 2017. Replacing alfalfa silage with tannin-containing birdsfoot trefoil silage in total mixed rations for lactating dairy cows. Journal of Dairy Science. doi: 10.3168/jds.2016-12073.
Duff, A., Zedler, P.H., Barzen, J.A., Knuteson, D.L. 2017. The Capacity-Building Stewardship Model: Assessment of an agricultural network as a mechanism for improving regional agroecosystem sustainability. Ecology and Society. doi:10.5751/ES-09146-220145.
Sripathi, R., Conaghan, P., Grogan, D., Casler, M.D. 2017. Field design factors affecting the precision of ryegrass forage yield estimation. Agronomy Journal. 109:858-869.
Sripathi, R., Conaghan, P., Grogan, D., Casler, M.D. 2017. Spatial variability effects on precision and power of forage yield estimation. Crop Science. 57:1383-1393.
Chen, S., Kaeppler, S., Vogel, K.P., Casler, M.D. 2016. Selection signatures in four lignin genes from switchgrass populations divergently selected for in vitro dry matter digestibility. PLoS One. doi:10.137/journal.pone.0167005.
Serapiglia, M., Dien, B.S., Boateng, A.A., Casler, M.D. 2017. Impact of harvest time and switchgrass cultivar on sugar release through enzymatic hydrolysis. BioEnergy Research. 10:377-387.
Serapiglia, M., Mullen, C.A., Boateng, A.A., Dien, B.S., Casler, M.D. 2017. Impact of harvest time and cultivar on conversion of switchgrass to bio-oils via fast pyrolysis. BioEnergy Research. 10:388-399.
Riday, H. 2017. Seed-parent fecundity distributions in bee-pollinated forage legume polycrosses. Crop Science. 57(3):1504-1510.
Casler, M.D., Grabowski, P.P. 2016. Genome-wide associations with flowering time in switchgrass using exome-capture sequencing data. New Phytologist. 213:154-169.
Casler, M.D., Sosa, S., Hoffman, L., Mayton, H., Ernst, C., Adler, P.R., Boe, A., Bonos, S.A. 2017. Biomass yield of switchgrass cultivars under high-input vs. low-input conditions. Crop Science. 57:821-832.
Casler, M.D., Jung, H. 2017. Lignin and etherified ferulates impact digestibility and structural composition of three temperate perennial grasses. Crop Science. 57:1010-1019.
Casler, M.D., Brink, G.E., Cherney, J.H. 2017. Registration of Azov meadow fescue. Journal of Plant Registrations. 11:9-14.
Collier, S., Ruark, M., Naber, M., Andraski, T., Casler, M.D. 2017. Apparent stability and subtle change in soil carbon and nitrogen under a long-term fertilizer gradient. Soil Science Society of America Journal. 81:310-321.
Riday, H., Johnson, D.W., Darling, M.E. 2016. Measuring the inefficiency of allowing self-pollinated alfalfa progeny into breeding nurseries. Crop Science. 57:161-167.
Riday, H. 2016. Field testing Northern U.S. adapted 2,4-D resistant red clover (Trifolium pratense L.). Crop Science. 56:2314-2321.