1a. Objectives (from AD-416):
1: Identify, through experimentation and plant growth and habitat modeling, pasture-based dairy and livestock production systems and management practices that improve food security by enhancing productivity, improving long-term environmental sustainability, and increasing flexibility to adapt to changing environmental and climatic conditions. We will initially delineate current land-use practices for grazing lands in the eastern US and investigate how land use might change in the future (sub-objective 1.A). Primary land use practices to be considered are pasture-based animal agriculture and bioenergy feedstock production systems. Sub-objective 1B will characterize potential changes in forage species distribution and dairy cow grazing behavior in response to climate change (adaptation), and evaluate plant and animal management strategies to mitigate climate change. Sub-objective 1.C will identify conservation practices and animal management strategies that improve nutrient utilization efficiency and reduce sediment and nutrients movement off-farm. 2: Develop best management practices and identify management systems that improve productivity and environmental sustainability of bioenergy production as part of multifunctional agricultural systems. Objective 2 focuses on bioenergy cropping systems and will identify management systems that increase soil C sequestration and reduce N loss and net GHG emissions (sub-objective 2.A) and evaluate the effects of miscanthus production at the commercial scale on C sequestration and GHG intensity (sub-objective 2.B). Sub-objective 2B will also include a life-cycle inventory assessment to profile the energy and GHG emissions associated with miscanthus production.
1b. Approach (from AD-416):
This research will provide the necessary information for developing decision-support tools that bring together diverse forage production systems, innovative animal management strategies and novel biofuel production practices to build multifunctional farms and landscapes. The purpose is to provide guidance on optimizing the placement and management of pasture and bioenergy crops in ways that are appropriate to the landscape context and that will increase productivity and enhance ecosystem services of farming enterprises. We will initially delineate current land-use practices for grazing lands in the eastern US and investigate the production and environmental consequences of potential future management changes. Primary land-use practices to be considered are pasture-based animal agriculture and bioenergy feedstock production systems. We will provide information on plant and animal adaptation to climate change and on the effectiveness of greenhouse gas (GHG) mitigation strategies for grazing animals, pasturelands, and biofuel feedstock production systems. We will provide farm scale life cycle inventory (LCI) data on miscanthus and identify water quality and GHG impacts of switchgrass and miscanthus production on marginal lands We will also assess the effects of grazing management and manure application strategies on nutrient movement and water quality as part of the pasture component of the national Grazing Lands Conservation Effects Assessment Project (CEAP). Results will fill gaps in our knowledge of management practices that increase resilience to climate change, improve conservation of soil and water resources, and reduce GHG emissions. Successful completion of this project will 1) increase farm productivity, 2) improve adaptation to climate change and 3) provide targeted conservation practices to enhance ecosystem services.
3. Progress Report:
Under sub-objective 1.A.1, Extensive topographic, climatic and soils data have been collected and processed for the northeastern United States. Regression tree and random forest techniques have been tested on subsets of the spatial data to identify tools that are statistically reliable and computationally feasible. Under sub-objective 1.A.2, Information on land use from National Land Cover Data and from USDA National Agricultural Statistical Service records has been compiled to provide baseline data on actual distribution of agricultural and other uses. Biofuels species distribution and abundance data from previous and ongoing ARS research are being supplemented by data from experimental trials and herbarium records. Under sub-objective 1.B.1, Forage species distribution and abundance data were obtained from ARS studies, forage variety trials and experimental station plots. Random forest and generalized additive models have been identified as having the greatest predictive power, but consensus models that integrate results from several techniques may be most effective overall. Under sub-objective 1.B.2, Kelp meal (KM) fed to grazing dairy cows had no impact on milk yield, milk components or heat stress indicators but increased milk iodine by 77% in KM fed cows which may be of concern for human health. Under sub-objective 1.B.3, The perennial grasses switchgrass and reed canarygrass were harvested in August, November and April. Other management practices were completed as appropriate during growing season. Under sub-objective 1.B.4, Feeding incremental levels of ground flaxseed to grazing dairy cows decreased milk yield, milk components and methane output linearly which corresponded to linear reductions in intake. Under sub-objective 1.C.2, Unit-source watersheds were established on an old hay field and on a newly seeded orchardgrass field. Preliminary N2O emission and yield data were collected from the old hay field. Under sub-objective 1.C.3, continuous, rotational, and mob grazing were applied to three small watersheds to analyze the water quality of runoff collected from rainfall simulation plots. Data collection will be completed at the end of the 2013 grazing season. Under sub-objective 2.A.1, Field plots of miscanthus and switchgrass were established at FD-36 and Mattern watershed. Baseline soil carbon data was collected along with water quality, soil N2O emissions, and biomass yield. 2.A.2, Field plots of switchgrass were established at 4 locations and biochar treatments initiated. Baseline soil carbon data was collected along with soil N2O emissions and biomass yield. Under sub-objective 2.B.1, Field locations were selected to represent the suite of previous land use history. Baseline soil carbon data were collected, shallow cores prior to plowing, deep cores after, along with several further shallow core sampling events. Under sub-objective 2.B.2, Fuel consumption by farm equipment was measured during field preparation, and miscanthus planting and harvest.