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Item Is the U.S. cover crop seed industry ready to support projected adoption rates? A snapshot of the industry(2024) Wilson, Kelly R.; Hendrickson, Mary K.; Milhollin, Ryan; Weber, J. Alan; Myers, Robert L.; 0000-0002-8462-0586 (Wilson)"In recent years, interest in adoption of cover crops on U.S. farmland has surged in the public and private sectors, as well as with farmers. Cover crops are crops planted to cover the soil and reach different climate and soil health benefits, such as reducing erosion; increasing water availability; and providing weed, pest or disease control; and to enhance biodiversity on a farm (Clark 2015). To promote use of climate-smart practices such as cover crops, the federal government launched new funding programs, including the Partnerships for Climate-Smart Commodities program, which invested $3.1 billion in projects providing financial and technical assistance to farmers and ranchers (USDA 2024). Several private companies have their own initiatives to incentivize farmers to use cover crops (Marston 2022). In their own right, farmers across the country are using cover crops at higher rates to reach specific objectives, such as building soil health and accessing these cover crop incentive payments (SARE, ASTA, and CTIC 2020). With heightened investment--and interest--in cover crop adoption, we are faced with the question of whether the seed industry is prepared to meet the demand for quality cover crop seed. Evidence suggests that farmers currently perceive lack of seed availability as a key constraint to using cover crops (CTIC and SARE 2020). Although this lack points to a potential market opportunity for seed producers and companies, this industry is unique because cover crops are typically considered a noncash crop. Cover crop seed may, therefore, not have the supportive infrastructure available to cash crops such as soybean and corn. To ensure that efforts to extend adoption of cover crops are fruitful, the cover crop seed industry needs to be bolstered and expanded. This paper examines the present state of the cover crop seed industry, drawing from U.S. Census of Agriculture data; literature reviews of academic studies, news reports and white papers; and qualitative interviews conducted with representatives involved in the cover crop seed industry. We interviewed seven individuals who lead or work for seed companies that sell cover crop seed in North America. We asked interviewees to describe how their company operates, from seed production to sales. We then asked for their perspectives on the U.S. cover crop seed industry today, the biggest opportunities and challenges facing the industry, and what policies are programs they see as beneficial or crucial to growing the cover crop seed industry. We conducted qualitative analyses of interview transcripts to draw out key themes and unique perspectives. From these interviews and the above mentioned available information, we seek to provide a baseline for where the U.S. cover crop seed industry is today, in 2024. We start by describing, first, the trajectory of cover crop adoption in the U.S., and then, current drivers. Next, we analyze U.S. agricultural census data to describe our current domestic and imported supply of cover crop seed. We then provide overviews of the cover crop seed production cycle, types of cover crop seed suppliers, and the major players in the industry today. From there, we present key challenges facing the cover crop seed industry today, describe opportunities for the industry to evolve, and discuss future considerations."--Introduction.Item Changes in the atmospheric circulation conditions and regional climatic characteristics in two remote regions since the mid-20th century(MDPI AG, 2019) Lebedeva, M.G.; Lupo, A.R.; Chendev, Y.G.; Krymskaya, O.V.; Solovyev, A.B.; School of Natural ResourcesA meridional Northern Hemisphere (NH) circulation epoch, which began in 1957, is marked by changes in the temperature and precipitation regimes over southwest Russia and central USA depending on the occurrence of NH atmospheric circulation regimes. A classification scheme proposed in 1968, and studied later put forth 13 NH circulation types, fitting more broadly into four groups, two of which are more zonal type flows and two of which are more meridional flows. Using the results of a previous study that showed four distinct sub-periods during the 1957-2017 epoch, the temperature and precipitation regimes of both regions were studied across all seasons in order to characterize modern day climate variability and their suitability for vegetation growth. Then the Hydrologic Coefficient, which combined the temperature and precipitation variables, was briefly studied. The most optimal conditions for vegetation growth, positive temperature and precipitation anomalies, were noted during the period 1970-1980 for southwest Russia, which was dominated by an increasingly more zonal flow regime in the Belgorod region and NH in general. For the central USA, the HTC showed more ideal conditions for agriculture in recent years due to favorable precipitation occurrence. In southwest Russia, variable precipitation regimes were noted during the meridional flow periods, and with the increase in temperature (since 1998), these can adversely affect the hydrothermal characteristics of the growing season. Finally, a comparison of the 13 NH circulation types with several teleconnection indexes demonstrated the robustness of the NH flow regime classification scheme used here.Item Changes in global blocking character in recent decades(MDPI AG, 2019) Lupo, A.R.; Jensen, A.D.; Mokhov, I.I.; Timazhev, A.V.; Eichler, T.; Efe, B.; School of Natural ResourcesA global blocking climatology published by this group for events that occurred during the late 20th century examined a comprehensive list of characteristics that included block intensity (BI). In addition to confirming the results of other published climatologies, they found that Northern Hemisphere (NH) blocking events (1968-1998) were stronger than Southern Hemisphere (SH) blocks and winter events are stronger than summer events in both hemispheres. This work also examined the interannual variability of blocking as related to El Niño and Southern Oscillation (ENSO). Since the late 20th century, there is evidence that the occurrence of blocking has increased globally. A comparison of blocking characteristics since 1998 (1998-2018 NH; 2000-2018 SH) shows that the number of blocking events and their duration have increased significantly in both hemispheres. The blocking BI has decreased by about six percent in the NH, but there was little change in the BI for the SH events. Additionally, there is little or no change in the primary genesis regions of blocking. An examination of variability related to ENSO reveals that the NH interannual-scale variations found in the earlier work has reversed in the early 21st century. This could either be the result of interdecadal variability or a change in the climate. Interdecadal variations are examined as well.Item Herbaceous encroachment from mountain birch forests to alpine tundra plant communities through above- and belowground competition(MDPI AG, 2019) Tan, X.; He, H.S.; Zong, S.; Wu, M.; Liu, K.; Zhao, D.; School of Natural ResourcesAlpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.Item Evaluating k-nearest neighbor (kNN) imputation models for species-level aboveground forest biomass mapping in Northeast China(MDPI AG, 2019) Fu, Y.; He, H.S.; Hawbaker, T.J.; Henne, P.D.; Zhu, Z.; Larsen, D.R.; School of Natural ResourcesQuantifying spatially explicit or pixel-level aboveground forest biomass (AFB) across large regions is critical for measuring forest carbon sequestration capacity, assessing forest carbon balance, and revealing changes in the structure and function of forest ecosystems. When AFB is measured at the species level using widely available remote sensing data, regional changes in forest composition can readily be monitored. In this study, wall-to-wall maps of species-level AFB were generated for forests in Northeast China by integrating forest inventory data with Moderate Resolution Imaging Spectroradiometer (MODIS) images and environmental variables through applying the optimal k-nearest neighbor (kNN) imputation model. By comparing the prediction accuracy of 630 kNN models, we found that the models with random forest (RF) as the distance metric showed the highest accuracy. Compared to the use of single-month MODIS data for September, there was no appreciable improvement for the estimation accuracy of species-level AFB by using multi-month MODIS data. When k > 7, the accuracy improvement of the RF-based kNN models using the single MODIS predictors for September was essentially negligible. Therefore, the kNN model using the RF distance metric, single-month (September) MODIS predictors and k = 7 was the optimal model to impute the species-level AFB for entire Northeast China. Our imputation results showed that average AFB of all species over Northeast China was 101.98 Mg/ha around 2000. Among 17 widespread species, larch was most dominant, with the largest AFB (20.88 Mg/ha), followed by white birch (13.84 Mg/ha). Amur corktree and willow had low AFB (0.91 and 0.96 Mg/ha, respectively). Environmental variables (e.g., climate and topography) had strong relationships with species-level AFB. By integrating forest inventory data and remote sensing data with complete spatial coverage using the optimal kNN model, we successfully mapped the AFB distribution of the 17 tree species over Northeast China. We also evaluated the accuracy of AFB at different spatial scales. The AFB estimation accuracy significantly improved from stand level up to the ecotype level, indicating that the AFB maps generated from this study are more suitable to apply to forest ecosystem models (e.g., LINKAGES) which require species-level attributes at the ecotype scale.