Progress 09/01/23 to 08/31/24
Outputs
Target Audience:In our first year our target audience was students that we are recruiting as well as scientists, farmers, NGOs, and state agency employees that may beinterested in collaborating. We do not yet have results that would be appropriate to disseminate to farmers. Changes/Problems:Originally, we planned to divide the Penn State Research Station site into equal areas for the perennial and annual rotations. Instead, we decided to utilize one-quarter of the site for the perennial rotation (20-foot strips) and leave the remaining three-quarters of the site in the established annual rotation (60-foot strips). Over the last 12 years, we have built collaborations with several other research groups who are continuing their projects the annual rotation. This will allow sufficient space for all these research activities that are in progress without compromising the objectives for the new perennials project reported on here. A PI on this project (Arrington) accepted a job that was not "soft money" grant funded. We decided to replace them with a PhD student, which we successfully recruited. That PhD student will start in January 2025 and we don't anticipate any major changes to our objectives. What opportunities for training and professional development has the project provided?Five undergraduate students gained research experience part-time during the 2023-24 school year, and three interns gained training on this project via in Summer 2024. Undergraduate students contributed to this project by testing the method to separate the particulate organic matter fraction from soil samples (a new method in the laboratory), testing seed germination, preparing seed packets, planting perennial forages, and collecting soil infiltration measurements. In addition, they participated in weekly lab group planning meetings where they had opportunities to learn about other projects and provide feedback on draft manuscripts and presentations. We have recruitedone MS student to start Fall 2025 and one PhD student to start in January 2025. Two technicians learned about forage management through this project. One of them, Brosi Bradley, attended PSU extension organic learning circle that included some discussion of various crop rotations including perennials vs annual cover crops. How have the results been disseminated to communities of interest?There are not results to share with communities of interest yet. However, several groups have toured the site to observe the new perennial part of the rotation. Caroyn Lowry took AGRO 28 (Principles of Crop Management Class) and Jason Kaye used the research site as a field trip tour for SOILS 502 (The Nature and Properties of Soils). We also were part of the Penn State Organic Cropping Systems Research Tour on August 14, 2024. Attendees toured the perennials and annual comparison during tour. Approximately 20 people attending as members of the state wide Organic Ag Working Group,consisting mainly of NGOs working in this sector (PCO, PASA, Rodale) and various officials in the Pennsylvania Department of Agriculture. The perennial establishment and annual comparisons were discussed during a field tour of PSU organic crop sites on September 4th, 2024, at the RELARC Cover Crop Cocktails sitethat was for organic growers and certifiers from Argentina. The organizer was Pedro Landa from OIA, Argentina. Discussion included similarities between organic grower challenges of weed and nutrient management and the benefits (or even necessity) of a perennial component of a crop rotation. What do you plan to do during the next reporting period to accomplish the goals?Entry 1: planted 2024: We will complete the 2nd year forage harvests and measurements of forage yield, quality, as well as species composition at 2 time points over the summer. For the annual comparison plots, we will measure wheat yield and harvest, then establish annual cover crop treatments in late August. We will manage soil fertility by analyzing soil samples for nutrient levels and pH, and adding manure after first harvest cut at suitable and consistent rate across all treatments (both perennial and annual). Entry 2: to be planted spring 2025: We will complete baseline soil sampling (0-20 cm depth) prior to perennial forage planting, then analyzesoil for particulate fraction of the soil organic matter as well as aggregate stability, as well as complete infiltration measurements on a subset on plots using the double ring infiltrometer. We will establish the perennial treatments as proposed then measure stand counts for establishment, maintain weed control through mowing, or forage harvest as applicable, and sample biomass in the fall to quantify establishment and growth. We will characterize the baseline soil weed seedbank community in the second perennial forage entry. The annual crop comparison plots will have soybean planted, cultivated, yield measured, then harvested and winter wheat drilled in the fall of 2025. Entry 3: to be planted spring 2026: We will survey the Canada thistle populations in the final perennial forage entry and take soil samples to analyze for fertility, pH to adjust as needed for perennial establishment. We will also meet with farmer advisors, select on-farm research sites, finalize protocols for on-farm sampling and begin measurements on-farm sites.
Impacts
What was accomplished under these goals?
The experiments are being conducted at our Penn State Research Station, which has an organically managed field with an established annual rotation of corn-soybeans-wheat with cover crops. A diverse set of cover crops are grown between wheat and corn, including six cover crop monocultures and five mixtures (2 to 6 species).Cereal rye is grown on all plots (except for a fallow control) between corn and soybeans. The site is divided into three entries, with each entry in a different phase of the rotation, so that all three cash crops are grown each year in different sections of the field. In the first year of the project, we began the establishment of perennial forages during the cereal rye phase of the rotation in one entry of the field. Objective 1: Evaluating Forage Yield and Quality We selected the following varieties for the six perennial species: Alfalfa (44 Mag organic), Birdsfoot trefoil (conventional raw seed, variety not stated), Tall fescue (Lipalma organic), Orchardgrass (Lipalma organic), Forage Chicory (Forb Feast Chicory, untreated), and Small burnet (Delar, conventional raw seed). Conventional untreated seed was used when organic seed was not available from three or more suppliers. For the legumes, species-specific inoculants were used to ensure the presence of correct species of rhizobial bacteria. The alfalfa inoculant was in a seed coating, while a separate inoculant was used for the birdsfoot trefoil. Perennial varieties were selected based on characteristics such as maturity timing, fall dormancy and winter survival with a goal of all species being ready for hay cutting at similar times throughout the growing season. Perennial species seeding rates were selected based on Penn State and NRCS recommendations, with the following rates (pounds per acre) for monocultures: Birdsfoot trefoil (8), Alfalfa (15), Tall fescue (12), Orchardgrass (12), Forage chicory (4) and Small burnet (20). For the mixtures, we combined 2 to 6 perennial species to match the number of species and functional groups (legumes, grasses and brassicas) in the cover crop mixtures. Since brassicas are not typically grown as forages, we selected perennial forb species (forage chicory and small burnet) to correspond with the cover crop brassica species. In the perennial mixtures, equal fractions were multiplied by the monoculture seeding rates for each species, i.e. the 2-species mixture was 50% of the alfalfa monoculture rate plus 50% of the orchardgrass monoculture rate. When preparing seed packets for planting, seeding rates were adjusted based on germination rates measured in our lab for each species, which ranged from 71 to 95%. In the first entry where perennial forages would be planted, corn was harvested for grain in mid-October 2023. After chisel plowing, disking and cultimulching, cereal rye was drill planted in late-October. In March 2024, we initiated the split between the annual and perennial rotation by mowing 20 feet of cereal rye in each strip. The remaining cereal rye in each strip (60 feet) would continue in the annual rotation. After moldboard plowing, disking, s-tine cultivating and cultimulching, the perennial forages were planted in late April. Each perennial monoculture or mixture was planted in a plot which corresponded in both the number of species and plant functional groups to the history of cover crop planting between wheat and corn. For example, the legume-grass perennial mixture (alfalfa-orchardgrass) was planted in plots that have a history of legume-grass cover crops. The established annual rotation at this site includes control plots that have been fallow in winter for two out of three years of the annual rotation: between wheat and corn and between corn and soybeans. (While fallow, these plots have been cultivated for weed control except for a small area used for weed assessments.) Since the perennial forages will be grown for two years before corn, we decided to use an alternative control to prevent areas of the field from being fallow for two years. The plots with a winter fallow history were divided into eight subplots, which was the smallest subdivision we could create with our planting equipment. In these subplots, we planted a subset of the 11 perennial treatments: 5 monocultures (all species except small burnet) and 3 mixtures (all that do not include small burnet). This subset will allow us to test if there is a legacy of cover crops by comparing soil health and weed metrics for each species with and without a history of cover crops in the annual rotation. In the entry where the perennial forages were planted, the operations for the annual rotation management were consistent with previous years. Cereal rye was mowed in mid-May and these strips were moldboard plowed, disked s-tine cultivated, and soybeans were planted in mid-June. Right after planting, soybeans were tine-weeded and then cultivated weekly until mid-July to control weeds. Perennials planted in April 2024 were mowed twice over the summer to control annual weeds. We measured stand counts ~ 3 weeks after planting, and fall biomass growth of all perennial treatments, separated by species and weeds. The annual crop for the split plot comparison for Entry 1 was soybeans, which were planted in spring 2024, then cultivated for weed control, and finally harvested with yield records by plot. Following the harvest, the soil was prepared for planting (chisel plow and following operations), then planted to winter wheat ?Objective 2: Soil Health In March, baseline soil samples (0 to 20 cm soil depth) were collected prior to field operations to begin the division between the perennial and annual rotations. These samples have been analyzed soil for particulate organic matter fraction as well as wet aggregate stability as proposed. In May, we collected baseline soil infiltration measurements in plots that had a history of winter fallow and those that had a history of a 4-species cover crop mixture planted before corn (three randomly selected locations per plot). In the plots with the winter cover crop history, cereal rye was clipped from a 0.25m2 quadrat to clear an area for the infiltration measurements and to estimate cereal rye biomass. Infiltration rates were measured with a double-ring infiltrometer, with a 15 cm diameter inner ring and a 30 cm diameter outer ring, 10 cm tall, inserted to a depth of 5 cm. For each infiltrometer, measurements were recorded until steady state was reached, which was defined as three or more measurements varying by less than 10%. Objective 3: Weed Suppression In Entry 1, which was planted to perennials in April 2024, we sampled the soil seedbank to evaluate the baseline seedbank community prior to the perennial forages being planted. We placed soil in flats in the greenhouse for 6 months and periodically disturbed and homogenized the soil until germination of all weed seedlings was completely exhausted. Entry 2, which will be planted with perennials in April 2025, we surveyed the baseline Canada thistle population to evaluate whether the perennial forage treatments affect Canada thistle density. Object 4: Corn yields and profitability We have been collecting corn yields following the diverse set of winter cover crops (11 treatments with a fallow control) as part of previous projects using the annual rotation. The fourth round of the three-year annual rotation will be completed with corn yield measurements collected in Fall 2024. The historical yield data will document the corn yield-variability at this site. The analyses comparing the corn yields and profitability for the perennial and annual rotations will occur after the first corn harvest following two years of perennial forages.
Publications
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