Progress report for ONE22-428
This project seeks to: (1) Evaluate four improved switchgrass cultivars and two improved big bluestem cultivars across three farms. (2) Measure 1st year grass seedling counts, 1st 2nd and 3rd year fall sward height and 2nd and 3rd year fall biomass yield. (3) Communicate results to interested parties through online communications, social media, a presentation at the Association of Warm Season Grass Producers annual meeting, and through formal publications.
Widespread adoption of native grass agriculture could diversify the landscape and rural economy. Specifically, native grasses can improve environmental outcomes while creating new markets for sustainable bio-products. Increasing the footprint of perennial crops on the landscape provides greater habitat for a range of insect, mammal, and bird species. Further, deep rooted perennials can increase soil carbon and reduce soil loss and nutrient run-off. For farmers, native grasses can be profitable by providing high-yield, low-input biomass or forage for livestock, particularly when grown on lands unsuitable for annual crops. Promising new incentives for farmers are also being proposed through carbon offsets credits or nutrient credits. In Pennsylvania specifically, nutrient credit programs such as Chesapeake Bay Nutrient Credit Trading program provides a model where farmers are paid for improved land management practices.
Despite these opportunities, perennial native grass adoption has been slow. This is driven by a chicken-and-egg issue where farmers are unwilling to adopt a crop that lacks an established marketplace. Further, without a robust community of farmers testing new methods and varieties, the best practices in native grass agronomics are uncertain. The Association of Warm Season Grass Producers is seeking to remedy both of these issues by collaborating to recruit buyers of grass biomass and to share insights among farmers regarding best practices. A recent opportunity has arisen because multiple member farmers have reported fields with low yields due to a combination of older varieties, weed build-up and disease pressure. These fields were established using a “first generation” switchgrass cultivar Cave-In-Rock, along with a mixture of big bluestem and other grassland species. Improved varieties could provide greater yield and disease resistance, but many new varieties have not been tested in the region. Establishment and yield data on improved native grass varieties can provide current farmers with valuable information and could make native grass production more appealing to prospective farmers.
Native grass establishment is currently risky due to the risk of failed or weak grass stands. Native grasses establish slowly and produce negligible yields during the first year and reduced yields during 2nd and 3rd season. Breeding programs have focused on improving native grass germination rates and seedling vigor. The strongest example of this is the program REAP Canada (Resource Efficient Agricultural Production) which has adopted a single-year breeding cycle based on vigorous upright growth during the establishment year. This program has developed multiple cultivars including RC Big Rock, a selection from the Cave-In-Rock switchgrass cultivar, and RC Crazy Horse, an improved big bluestem variety.
A second major source of improved varieties is through the adoption of lowland switchgrass ecotypes. Broadly, switchgrass occurs as two primary ecotypes: upland and lowland. Lowland ecotypes tend to grow in the southern United States, while upland ecotypes are native to the northern United States. The majority of farmers in the northeast region use an upland ecotype. Agronomically, lowland ecotypes have greater yield potential and are disease resistant. However, lowland ecotypes are prone to winterkill and poor vigor when grown in the northern United States. Recent breeding efforts, however, have created multiple winter-tolerant lowland cultivars. These lowland ecotypes can increase biomass yield by approximately 50%, but rigorous field comparisons have not occurred. Further, different breeding programs have released multiple lowland populations which have not been rigorously compared in the Northeast. This study proposes to evaluate the improved lowland switchgrass cultivars Timber, Independence, and Cedar Creek. Timber is a cultivar generated from multiple populations native to the Northeast and was released by the Cape May Plant Materials Center. Independence is a release from the University of Illinois and was created from individuals selected for high biomass and vigor from the cultivar Kanlow. Cedar Creek was created in Wisconsin from a Kanlow-derived breeding population which was selected for multiple cycles of winter survival as far north as plant hardiness zone 4.
Although more research effort has been dedicated to switchgrass, multiple breeding programs have also focused on improved big bluestem cultivars. Anecdotally, big bluestem has been successfully planted with switchgrass by farmers in the region and improves yield stability across growing seasons and fields. This study will evaluate two new populations: RC Crazy Horse and Empire. The RC Crazy Horse population was described above. The Empire big bluestem population was selected for late flowering, which extends biomass accumulation and improves fall yields.
This study can provide important yield data for farmers and may also provide information to reduce the risks of sward establishment. Combined, this will improve confidence of farmers in the Association of Warm Season Grass Producers and can also encourage other farmers with marginal or erodible land to establish native grasses. This work can supplement ongoing projects being carried out by Pennsylvania State University which are aimed at improving grass riparian buffer adoption and on-farm bioenergy production.
- - Producer
- - Technical Advisor (Researcher)
- - Technical Advisor
- - Producer
In late May of 2023, the original sward will be renovated using standard methods. Briefly, the swards will be mowed and sprayed with glyphosate at the suggested rate prior to re-seeding. After seeding, the field will be cultipacked to improve seed to soil contact. The six varieties will be planted using a John Deere 750 no-till grass seed drill at a rate equivalent to 4 lbs PLS per acre. Seed for four varieties will be donated by Ernst Seeds and two varieties are being donated by active researchers. The experimental design will be an on-farm strip-plot design. Each grass variety will be planted in a 30’ by 120’ strip with 2 replicates of each variety per farm using completely randomized experimental design. First year weed control will include application of 2,4-D at the suggested rate for control of broad-leaf weeds, and summer mowing to reduce weed competition.
Establishment success will be measured by the following: In late July of 2023, seedling counts will be carried out at 8 randomly selected locations within each plot by recording the number of switchgrass seedlings per 2-meter length of row. Shortly after the first frost of 2023, 2024, and 2025 mean fall sward height will also be recorded every 10’ of a transect running through the center of each plot, not including edges, resulting in 10 observations per plot. Biomass accumulation is negligible during the establishment year, but in 2024 and 2025 fall biomass yield will be measured by hand clipping and weighing 9 square foot quadrats in early-November. Aboveground biomass will be clipped at standard mowing height and weighed in-field using a hanging scale. Each plot will be sampled 5 times at equidistant points along a transect through the center of each plot. One sample per plot will be dried to calculate an adjustment for moisture content.
Analysis will be carried out using a mixed-effects model. Specifically, cultivars will be modeled as random effects to generate best linear unbiased predictors for yield performance through quadrat samples of biomass, 1st year seedling counts, and fall height. The effect of farms and growing season will be modeled as fixed effects. A random variety-by-farm interactive effect will be included to measure the yield stability of different cultivars among farms. Further, fall plant height measurements are a surrogate for biomass yield. Therefore, fall height and fall biomass yield can be analyzed with a multi-trait model which includes an internal estimate of the correlation between the two measurement methods (height and biomass). Further, the combined fall biomass and height measurements can be used to quantify and adjust for within plot heterogeneity at each farm.
This research project officially began August 1, 2022 and is expected to be carried out through November 30, 2025. The original project proposal plan is based on planting the six trial varieties of warm season grass on three separate farms in the spring of 2023. A pre-planting herbicide application plan was developed in the fall of 2022 by the researchers and participating producers. The necessary herbicide to be applied to the plots, plot marking stakes, and marking flags for the project have been purchased for the project. A WSG Variety Trial Spray Plan was prepared and provided to the participants.
One of the three original warm season grass producers committed to the project (Rodney Leighow) has notified us that he is declining to participate in the project for personal reasons, however, another agricultural landowner (Ann Roberts) has been added as the third farm to be planted with the trial varieties and evaluated for this project. The Roberts farm is leased to Bruce Trumbower who will actively carry out and manage that trial planting as well as the plantings on his own farm in collaboration with Neal Tilhou (researcher). The actual trial plantings are scheduled for spring of 2023.
Education & Outreach Activities and Participation Summary
Preliminary discussions have taken place between the Association of Warm Season Grass Producers, the grantee principal investigator(Wes Ramsey), and Neal Tilhou (the project researcher) to define the intent of the project and prepare a pre-planting herbicide application plan in cooperation with the three producers identified as participants in the project. Three farm owner/operators (Bruce Trumbower, Eileen Arnold, and Ann Roberts) have committed to providing the necessary land and services to participate in the project.
The results of this study will be communicated to the public through multiple channels. Preliminary results will be presented at the Association of Warm Season Grass Producers meeting in 2024, and final results will be reported at the 2025 meeting. Final results will also be posted to the Association website https://www.awsgp.org/ and e-mail list consisting of over 300 members and the results will also be published on the Penn Soil RC&D Council website www.pennsoil.org and social media pages. The Association of Warm Season Grass Producers also regularly presents at Ag Progress Days and can include information about the results of this trial. Also, results will also be used to draft a peer-reviewed paper which would include entirely novel yield data for these grass varieties and this region.