*This is not a comprehensive list of all research conducted at this time
Effects of landscape position on perennial biomass and food crop performance in buffer areas
Due to the environmental consequences of annual-dominated cropping systems, there is an increasing need to identify agronomic strategies that incorporate perennial crops. One strategy for increasing perennial cover is through the targeted use of annually harvested perennial food and bioproduct crops in buffer strips, which has the potential to create new revenue streams for farmers and substantially mitigate agricultural nutrient pollution from conventional cropping systems. As buffers are typically installed on marginal land, it is critical to understand how landscape position influences the success of perennial crops. The objectives of this study were to determine the relatively early influence of landscape position on the productivity of a variety of perennial crops and their subsequent soil nutrients and soil water storing capabilities. In this experiment, nine perennial (alfalfa, alsike clover, indiangrass, switchgrass, big bluestem, prairie cordgrass, intermediate wheatgrass, high-diversity polyculture, low-diversity polyculture) and two annual (corn, soybean) crops were planted across two landscape positions (hillslope and deposition). Plant biomass, plant tissue nitrogen, soil moisture, and soil NO3-N and NH4-N were measured and compared at two different locations in Minnesota. Overall, the polyculture mixes, and to some extent intermediate wheatgrass, performed the best with respect to biomass production while also providing ecosystem services across most soil by landscape position combinations tested in this study. However, there were some important findings specific to each soil and landscape position combination, mainly oriented toward biomass production. We also observed temporal patterns in soil moisture and depth-related patterns in soil N reductions. This study presents an opportunity to optimize the use of perennial crops on marginal agricultural lands for improved environmental and economic benefit.
Black, K. L., Johnson, G. A., Wells, S. S., Garcia y Garcia, A., Jungers, J. M., & Strock, J. S. (2024). Effects of landscape position on perennial biomass and food crop performance in buffer areas. Ecosphere, 15(7)https://doi.org/10.1002/ecs2.4908
Selection of Perennial Flax (Linum spp.) for Yield and Reproductive Traits for the Oilseed Ideotype.
Flaxseed has gained popularity as a health food. Wild, perennial Linum relatives of annual flax (L. usitatissimum) possess similar oil compositions, making them perennial oilseed (OS) alternatives. The objective of this study was to phenotype 25 OS and 17 cut flower (CF) breeding populations with 137 wild Linum species’ accessions in a common garden over three years (Y1–3) to quantify the impact of selection and identify top candidates. This study was intercepted by COVID-19, which prevented the same detailed phenotyping of Y1 from occurring in Y2–3. Traits measured from the perennial flax OS, in comparison with the CF ideotypes: weekly seed germination (Y1), yield per plant (Y1–3), seed weight (Y1–2), shattering (Y1–2), and seed capsule diameter (Y1). In Y1, OS selections had the highest yield per plant, followed by L. austriacum and then CF selections. The 1000 seed weights in Y1 were highest in annual flax, followed by L. grandiflorum and L. baicalense. Seed numbers/capsule were low in Y1–2, possibly due to shattering. Average yield per plant increased across Y1–3 indicating that, once plant establishment had occurred along with the potential for two harvests/year in Y2 onwards, significant OS yield can be realized. Harvest 1 yields were significantly higher than in harvest 2. In Y1–3, OS selections had the highest average seed yield. In Y1, OS and CF populations had smaller seeds, higher shattering, smaller capsule diameters, and lower germination than wild species. Significant breeding efforts are needed to increase perennial flax yield, using the multiple crop ideotypes.
Tork, D. G., Anderson, N. O., Wyse, D. L., & Betts, K. J. (2024). Selection of Perennial Flax (Linum spp.) for Yield and Reproductive Traits for the Oilseed Ideotype. Agronomy, 14(1), 99. https://doi.org/10.3390/agronomy14010099
The LTAR Cropland Common Experiment at Upper Mississippi River Basin–St. Paul.
The Soil and Water Management Research Unit of the USDA‐Agricultural Research Service is located in St. Paul, MN, and conducts long‐term research at the University of Minnesota Research and Outreach Center located at Rosemount, MN. As part of USDA's Long‐Term Agroecosystem Research (LTAR) network, the croplands common experiment (CCE) at this location is focused on integration of a kura clover (Trifolium ambiguum M. Bieb.) living mulch (KCLM) system into the prevailing 2‐year rotation of corn (Zea mays L.) and soybean (Glycine max L.) that is typical of the midwestern Corn Belt. The LTAR‐CCE conducted at Rosemount, MN, aims to compare the long‐term environmental and agronomic performance of KCLM while identifying challenges and developing management strategies for this alternative practice. The use of a living mulch for this region is advantageous because, once established, it does not require additional time for fall field operations typically associated with winter cover crops. Results from LTAR‐CCE studies at this site show that KCLM results in a substantial increase in soil field‐saturated hydraulic conductivity and decreases in leaching of nitrate‐nitrogen (NO₃⁻‐N). Disadvantages of the KCLM system include potential for increased emissions of nitrous oxide (N₂O) and reduced crop yields, particularly during drought. Also, the optimal approach for crop row establishment in the spring remains uncertain. Ongoing LTAR‐CCE research with KCLM aims to better understand and quantify both benefits and risks across conditions of interannual weather variability and changing climate to develop guidance for suitable adoption and management of this alternative practice.
Dalzell, B. J., Baker, J. M., Venterea, R. T. h. o., Spokas, K. A., Feyereisen, G. W. h. o., Rice, P. J., & Alexander, J. R. (2024). The LTAR Cropland Common Experiment at Upper Mississippi River Basin–St. Paul. Journal of Environmental Quality, 53, 1008-1016. https://doi.org/10.1002/jeq2.20615
Mechanical termination of a perennial grain crop minimally impacts soil structure, carbon and carbon dioxide emissions.
Introduction Mechanical termination of crops can negatively affect soil biological, chemical, and structural characteristics. Perennial crops do not require annual termination and can improve these same soil characteristics, which has catalysed interest in the development of new perennial crops. Advanced lines of the perennial grass intermediate wheatgrass (Thinopyrum intermedium Host] Barkworth and Dewey; IWG) have been bred for increased seed size and marketed as Kernza® perennial grain, but little is known about how this new crop can be terminated for subsequent annual crop production in rotations that enhance agricultural productivity and environmental sustainability. Materials and Methods Five methods of terminating IWG were tested in Minnesota, USA. Treatments included mechanical tillage using a chisel plow (CHI), undercutter (UND), and disc (DSC), along with no‐till treatments of glyphosate (GLY) and a repeated‐mowing control (CTRL). Treatment effects on IWG mortality, soil carbon dioxide (CO2) emissions, bulk density, aggregate stability, soil carbon stocks and soybean yield were measured. Results Daily CO2 fluxes differed by treatment (p < 0.05) on only one of 19 sample dates, and cumulative soil CO2 emissions over the course of the growing season did not differ across treatments. Bulk density decreased relative to baseline in all treatments except CTRL. Aggregate stability remained unchanged in all treatments except CTRL, which increased from the baseline. Soil carbon stocks did not change in any treatment. Soybean yield was highest in GLY but was not significantly different from CHI or UND. Conclusions Soil structure, soil carbon stocks and soil CO2 emissions were unaffected by tillage and no‐till IWG termination treatments. However, tillage followed by preplanting harrowing proved ineffective at terminating IWG and required subsequent summer herbicide applications. Therefore, additional tillage events may be required to fully terminate IWG when herbicide use is prohibited.
Kundert, J., Rakkar, M., Gutknecht, J., & Jungers, J. (2024). Mechanical termination of a perennial grain crop minimally impacts soil structure, carbon and carbon dioxide emissions. Journal of Sustainable Agriculture and Environment, 3(1)https://doi.org/10.1002/sae2.12094
Stover removal has minimal impact on pennycress seeded into standing corn
In the Upper Midwest, corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are the most prominent agricultural crops, occupying land for only half the year. Their fallow periods are associated with nutrient leaching and soil erosion, but they also represent an opportunity to establish winter-hardy crops, like pennycress (Thlaspi arvense L.), that can reduce negative environmental impacts while contributing to farm profitability. A lack of agronomic best management practices remains a barrier to pennycress adoption. The objectives of this study were to evaluate the impact of stover presence on pennycress stand establishment and seed yield after seeding pennycress into R4 corn. This study was conducted over the 2014–2015 and 2015–2016 growing seasons with MN106 pennycress at three locations in Minnesota. At maturity, corn plants were removed from plots in 25% increments between 0% and 100% to simulate stover removal scenarios. Pennycress seedlings were unable to compete with corn for available light resources and did not have enough time following corn harvest to establish a dense stand in the autumn with only 5% and 10% green cover in 2014 and 2015, respectively. Despite poor early season emergence, the average seed yield, 1223 kg ha−1, was high relative to other studies using MN106, indicating that challenges of growing pennycress under adverse conditions may not be a barrier to competitive seed yields. Experimentation on the corn–pennycress system should continue in the future to further explore and establish best management practices for this double crop.
Cubins, J. A., Wells, S., Johnson, G. A., Black, K. L., Perez, J., Gonch, A., Forcella, F., & Gesch, R. W. (2024). Stover removal has minimal impact on pennycress seeded into standing corn. Crop Science, 64, 1901–1909. https://doi.org/10.1002/csc2.21242
Spatial distribution and fixed-precision sequential sampling plans for Popillia japonica (Coleoptera: Scarabaeidae) adults in primocane raspberry: influence of foliar insecticides
The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), an invasive species from northern Japan, was first detected in Minnesota in 1968. According to fruit growers and the Minnesota Department of Agriculture, population size and feeding damage has been an increasing concern since 2010. Based on trap-catch data, populations have recently exceeded 4,000 beetles/trap/week during July-August near raspberry fields, and can increase by an order of magnitude within 7-10 days. The primary goals of this study were to assess the spatial distribution of P. japonica adults in raspberry, and to develop and validate a practical fixed-precision sequential sampling plan for grower use. Taylor’s Power Law (TPL) regression was used to characterize the beetle’s spatial pattern in research plots and commercial fields, either with or without insecticide applications. We then used Green’s plan to develop an enumerative sequential sampling plan to estimate P. japonica density in primocane raspberry. Beetle population data were collected at two locations in southern Minnesota, including the Rosemount Research and Outreach Center, and a commercial field near Forest Lake. The TPL results, via slope comparisons, indicated no significant differences in P. japonica spatial pattern between insecticide treated plots versus untreated plots, or among 4 different insecticides (P>0.05). Utilizing all spatial pattern data, we characterized the distribution of P. japonica beetles to be highly aggregated in raspberry, with TPL slopes ranging from b = 1.38 to 1.55; all slopes were found to be >1.0. Although the slopes were not significantly different, we accounted for variability in spatial pattern by using 33 independent data sets, and the Resampling for Validation of Sampling Plans (RVSP) model to validate a sampling plan with a final average precision level of 0.25 (SEM/mean), recommended for integrated pest management (IPM) purposes. The final sampling plan required an average sample number of only 15, 1-m-row samples, while providing high relative net precision (RNP), and thus a cost-effective, efficient sample plan for growers.
Toninato AG, Burkness EC and Hutchison WD (2024) Spatial distribution and fixed-precision sequential sampling plans for Popillia japonica (Coleoptera: Scarabaeidae) adults in primocane raspberry: influence of foliar insecticides. Front. Insect Sci. 4:1465829. doi: 10.3389/finsc.2024.1465829