Progress report for LNE23-480R
Project Information
Integrating crops and livestock enterprises can increase overall productivity of limited land bases that are typical of farms in the Northeast. Cover crops have been planted after harvest of crops such as small grains or corn silage to cover the soil over the winter and provide beneficial nutrients for subsequent crops. That said, some crops such as corn grain are harvested too late in the season for a cover crop to be established. Interseeding cover crops into growing corn has gained the interest of researchers and farmers as a method to provide a cover crop that is well established after the corn grain is harvested. Increasing feed and other input costs have farmers seeking lower-cost methods for feeding their livestock. There may be opportunity to better utilize the forage produced by the cover crops, such as grazing livestock on them to extend the grazing season and reduce feed costs. It is not yet known what the economic and environmental impacts of grazing these cover crops may have on subsequent crop production, nutrient use efficiency, or overall farm profitability. We hypothesize that interseeding annual forages into established corn fields will extend the forage production and grazing seasons, increase annual forage production per acre without impairing corn yield, reduce potential nitrogen loss, and increase nitrogen use efficiency of the crop system. To test this hypothesis, we will establish field plots and a grazing experiment to determine corn yield, interseeded forage yield, nutrient composition and uptake of corn and interseeded forages, and nitrogen use efficiency. Results of this research will provide farmers with practical recommendations on adoption of interseeding forages into growing corn to be grazed after corn grain harvest in the late fall and grazed again in early spring prior to corn planting.
Corn harvested as grain is taken too late in the season to establish a cover crop, therefore the land stands fallow over winter. Interseeding annual forages into established corn may act as a cover crop to reduce soil erosion and nitrate leaching. The objective of this project is to extend the forage production and grazing season through the utilization of grazed winter annuals and corn residue. Results of this research will provide farmers with novel management strategies to improve farm profitability and sustainability by increasing forage yield and nitrogen use efficiency along with decreasing feed costs.
Integrated crop-livestock systems have existed since the advent of agriculture, but these practices dwindled over the years due to farm specialization and mono-cropping. Rising concerns regarding natural resource degradation, farm profitability, and increased regulation of concentrated animal feeding operations have caused renewed interest in reintegrating livestock, pasture and cropping systems, particularly in the northeastern US that contains sensitive waterways such as the Chesapeake Bay and Lake Champlain regions.
Corn crops harvested as grain in late fall do not provide opportunity for a cover crop to be established. This land sits fallow over winter, resulting in increased potential for nutrient leaching and soil erosion. Cover crops interseeded into growing corn can provide an established cover crop after corn harvest to provide soil coverage over the winter.
Cover crops were initially planted for conservation benefits. However, with feed costs comprising >50% of operational costs on livestock farms, grazing these cover crops may provide opportunity to utilize this additional forage. Finding strategies to extend the grazing season beyond the traditional growing season could substantially decrease feed costs, thereby improving farm profitability. Grazing these cover crops could be one way to reduce stored feed costs and utilize the forage produced.
Of the approximately 31,000,000 beef cows in the United States, 407,000 are raised in the Northeast (USDA-NASS, 2021a). These include primarily cow-calf and backgrounding operations, both of which rely heavily on grazing. Additionally, of the approximate 14,000 dairy farms located in the Northeast (USDA-NASS, 2021b), 20-25% of these utilize grazing (Winsten et al., 2000), with approximately 1,000 of these farms being certified organic or grassfed that have specific grazing requirements (NODPA, 2021; AGA, 2022).
Many farmers are reluctant to plant or graze cover crops due to perceived concerns about significant cost with no immediate economic benefit, soil damage from animal hooves, and reduced ground cover after grazing. There is great opportunity to combine the need for low-cost feed along with the conservation benefits of cover crops into a novel approach to increase the overall economic and environmental sustainability of small farms. Grazing cover crops interseeded into cash crops could provide added revenues and increase nutrient cycling in the system while also providing conservation benefits that can affect long-term productivity and economics. However, the tradeoffs between cash crop productivity and environmental effects are not fully understood.
We have worked with farmers in the past who winter graze beef cattle in standing corn (George Lake, Thistle Creek Farms, Birmingham, PA) or extensively use cover crops on their dairy operation (Duane Hertzler, Moo-Echo Farms/Rock Hollow Dairy, Loysville, PA). These farmers have expressed interest in making further improvements to their forage management systems and better utilizing nutrients in the soil. Innovative farmers such as these need novel recommendations to expand their use of grazed forage to lower feed costs, meet specialty market needs (e.g., grassfed, organic) and reduce escalating input costs including fuel and fertilizer. This project will evaluate use of cover crops interseeded into corn for use as grazed forage after corn grain harvest.
Research
We hypothesize that interseeding annual forages into established corn fields will extend the forage production and grazing seasons, increase annual forage production per acre without impairing corn yield, reduce potential nitrogen loss, and increase nitrogen use efficiency of the crop system. To test this hypothesis, we will establish field plots and a grazing experiment to determine corn yield, interseeded forage yield, nutrient composition and uptake of corn and interseeded forages, and nitrogen use efficiency. These experiments will provide the project team with science-based recommendations for adoption of interseeded forages into standing corn for use as grazing crops after corn harvest.
Treatments
Forage Plot Study
Forage treatments include:
- Corn only (98-day maturity corn, 28,000 plants/ac)
- Corn (28,000 plants/ac) + cereal rye (110 lb/ac)
- Corn (28,000 plants/ac) + brassica (5 lb/ac)
- Corn (28,000 plants/ac) + cereal rye (110 lb/ac) + brassica (5 lb/ac)
These treatments were chosen based off our preliminary research at USDA-ARS as well as work published by others in other regions of the US (e.g., Liebig et al., 2015). Within each of the forage treatments, nitrogen will be sidedressed at 0, 40, 80, 120, 160, or 200 lb. nitrogen/ac annually, to assess corn and forage yield response to nitrogen.
Grazing Study
In spring 2023 (and again in 2024 and 2025), two 14-acre fields located approximately 1 mile apart at the Russell E. Larson Research Farm, Pennsylvania Furnace, PA will be planted in corn + cereal rye + brassica at the rates stated for the forage plot study.
Methods
Forage Plot Study
In late April/early May 2023 (and again in 2024 and 2025), plots will be established at the Russell E. Larson Agricultural Research Center, Pennsylvania Furnace, PA using a split-plot design with four replications where forage crop is the main plot and nitrogen fertilizer rate is the split plot (96 total plots). Short-season corn will be seeded in late April/early May, interseeded annual forages will be planted when corn reaches the V4-V6 growth stage (8- to 12-inch tall, early June).
Data collection
- Above ground corn biomass at physiological maturity, corn grain yield, and forage yield
- Nutrient composition of all forages and grain
- Prior to planting corn soil samples will be collected to six inches in the control plot of each replication to measure routine soil fertility parameters (pH, extractable phosphorus, available potassium, and organic matter). Just prior to sidedressing nitrogen, soil samples will be collected to one foot to assess nitrogen availability.
- Prior to planting corn, after corn harvest, and in the subsequent spring, soil samples will be collected to three feet in one-foot increments (or as deep as physically possible) and analyzed for soil nitrate. These data will be used to assess nitrogen availability, residual soil nitrate, and estimate nitrate leaching between seasons.
- Soil testing (pre-plant, after corn harvest in fall, after spring grazing)
- Soil compaction (penetrometer, bulk density). Prior to planting corn in the first year and just after killing the cover crop the following spring, soil compaction will be assessed with bulk density cores and/or penetrometer measurements.
- Economics (economic optimal nitrogen rate) Corn and forage yield response to nitrogen will be modeled and the economic optimum (most profitable) nitrogen rate will be calculated.
- Using corn and forage yield along with nutrient composition and feed quality, MILK 2010 can be used to estimate milk production per acre of land.
- Nitrogen use efficiency of corn, forage, and corn+forage will be evaluated using nitrogen uptake data.
Grazing Study
In late April/early May 2023 (and again in 2024 and 2025), two 14-acre fields located at the Russell E. Larson Agricultural Research Center, Pennsylvania Furnace, PA will be planted in short-season corn at 28,000 plants per acre. When corn reaches the V4-V6 stage, cool-season annual forages (cereal rye + brassica) will be interseeded at the same rates as the forage plot study into the 30-inch interrows of the corn using the Interseeder® no-till drill (Interseeder Technologies) (early June). Soil fertility will be added according to soil test recommendations to achieve optimal corn grain yields. Corn will be fertilized at planting and again at interseeding. After corn is harvested in late Oct/early Nov, fields will be left for 4 to 6 wk for annual forage to grow. Both fields will then be subdivided into 2-ac paddocks and randomly assigned one of two treatments (graze corn stover and forage, or no grazing). Twenty-four mid-pregnant beef cows (fall: 1000 lb average) or stocker beef cattle (spring: 800 lb) will be strip-grazed in the graze treatments until 90% of forage, and most of the corn stubble, is consumed. Cows will have ad libitum access to fresh water for the entirety of the study and will be managed under Penn State IACUC (Institutional Animal Care and Use Committee) protocols. Animal body weights will be collected on the home farm immediately before transport to the research plots (approximately 10 miles away) and again off the trailer upon return to the home farm.
Data collection
- Corn fodder, corn grain, and forage yield
- Nutritive value of all forages and grain
- Soil testing (pre-plant, after corn harvest in fall, after spring grazing)
- Soil compaction (penetrometer, bulk density)
- Economics (agronomic and economic optimal nitrogen rate)
- Nitrogen use efficiency
Data Analysis and Presentation of Results
Data will be summarized and analyzed utilizing a mixed procedure analysis (software: SAS Inst. Inc., Cary, NC), with adjustments made for assumptions of variance and conservative confidence value estimation and for determination of differences between treatments. Statistical model components will include fixed effects of cover crop and year and evaluate and all interactions. Additional adjustment may need made to the data, and all details of analysis will be reported with results at the time of data summary and report. During Years 2 and 3, Extension field days will be utilized to showcase the most recent available data. All data will be made available through Extension and collaborator publications. Data from this project will also be submitted for peer review and publishing in relevant scientific journals.
2023 Research Update
We are currently fall-grazing the interseeded corn fields (Dec 2023- Year 1). We will plant the forage plot study in spring 2024. We are also conducting a search to hire a post-doctoral research associate for the project.