Browsing by Subject "cover crop"

Now showing 1 - 7 of 7
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    Biological nitrogen fixation of winter annual legume cover crops in Upper Midwest horticultural cropping systems
    (2018-04) Perrone, Sharon
    Legume cover crops can play a valuable role in maintaining and increasing soil quality and nitrogen availability, but face unique challenges in the Upper Midwest, such as short growing seasons, cold, wet springs, and harsh winters. This study was performed to assess the viability of winter annual legume species in northern climates as a source of nitrogen fertility to a 75-day sweet corn crop (Zea mays convar. saccharata var. rugosa). Treatments included medium red clover (Trifolium pratense), two cold-hardy ecotypes of hairy vetch (Vicia villosa Roth), a cereal rye-hairy vetch biculture (Secale cereale L., Vicia villosa Roth), cereal rye as a non-legume control, and a fallow weed-free control. In 2015-2016, legumes were split into rhizobia inoculated and non-inoculated treatments. In 2016-2017, inoculation treatments were dropped due to no significant findings in biomass production and nodulation between inoculated and non-inoculated treatments. Cover crops were planted in fall 2015 and 2016 at the University of Minnesota Research and Outreach Centers located in Grand Rapids, MN and Lamberton, MN in a randomized complete block design. Total biomass, total nitrogen, and natural 15N abundance were determined for all site years, with nodule mass and number determined in 2015-2016 only. The rye monoculture and biculture produced the most biomass at all site-years ranging from 1.9-3.7 Mg ha-1, while a vetch ecotype (V2) produced as much biomass as the rye monoculture and bicultures in 3 of 4 site-years. Both vetch ecotypes contributed the most nitrogen in 2015-2016, while clover contributed less than rye mono- and bicultures at Grand Rapids in 2016-2017, and there were no significant differences in nitrogen contributions among all treatments in Lamberton in 2016-2017. Hairy vetch ecotype 1 contributed up to 85 kg N ha-1 from aboveground biomass. Data from natural abundance isotopic approaches indicate that 38-103% of vetch tissue N in Grand Rapids and 45-66% of vetch tissue N in Lamberton was derived from atmospheric N fixation, with equal or higher fixation of vetch in biculture at all site-years. Sweet corn yield was equal across all treatments, including a bare ground control. More studies should be performed to enhance N fixation in legume cover crops in the Upper Midwest.
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    Evaluating weed management decisions that influence cover crop adoption in the Upper Midwest
    (2022-12) Ley, Ethan
    The use of pre-emergence residual herbicides has proven to be an effective strategy for controlling problematic late-emerging weed species in annual crops. However, the use of residual preemergence (PRE) herbicides has the potential to negatively affect other crops within an annual two-crop rotation, such as fall-planted cover crops. The intent of this study was to determine if residual PRE herbicides would affect the emergence and growth of fall-planted cover crops. Four PRE herbicides, dimethenamid-p, a packaged mixture of dimethenamid-p + saflufenacil, a packaged mixture of acetochlor + clopyralid + mesotrione, and a layered treatment of dimethenamid-p 30 days after first application of dimethenamid-p were applied before silage corn planting. Following silage corn harvest in the fall, three cover crops, winter cereal rye (S. cereale ), winter camelina (C. sativa ), and red clover (T. pratense) were planted with a no-till drill at three locations in Minnesota that differed in soil type and climate. Plant measurements were obtained for each cover crop at burndown in the spring to assess establishment, growth and biomass. Cover crop height, plant density, and ground coverage in the spring were influenced by an interactions between cover crop species, herbicide, and location . However, there was no difference in the total biomass accumulation at termination the following Spring. These results indicate that application of these residual PRE herbicides for control of late-emerging weed species did not interfere with cover crop biomass production as long as soil moisture was at or above normal during the growing season.
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    Improving soil health and nitrogen cycling through zone tilled cover cropping practices for organic production
    (2017-07) Ginakes, Peyton
    Zone tillage is a reduced-tillage compromise between no-till and full-width tillage that attempts to capture both the environmental advantages of year-round ground cover and the agronomic benefits of in-row tillage. This management tool is especially well-suited to the practice of cover cropping, where plants are grown between cash crops in space, time, or both. Localizing the use of tillage in cover cropped systems may preserve soil quality between crop rows where soil is not tilled, as measured by soil microbial activity and varying indicators of soil organic matter, while also making N available only in crop rows. In this dissertation, two cover cropping systems were assessed for their contributions to soil quality and crop production: 1) a perennial kura clover (KC; Trifolium ambiguum) living mulch in corn (Zea mays), where KC persists between crops rows during the growing season to maintain ground cover of between-row areas, and 2) winter annual cover crops in an organic yellow crookneck squash (Cucurbita pepo) system, where cover crops were maintained between crop rows until they were fully mature, allowing for extended ground coverage and N provisioning. In the KC system, three tillage treatments and one no-till control were tested for their ability to incorporate KC residues between rows and to minimize KC competition with the corn crop. A novel PTO-driven rotary zone till implement was found to increase in-row soil N relative to both no-till and a less disruptive zone till implement consisting of a shank with ground-driven coulters. Corn yields were higher in treatments using this novel implement. In the winter annual system, three cover crop systems were examined at early and late terminations for cover crop N content and soil quality indicators: oat (Avena sativa) + field pea (Pisum sativum), winter rye (Cereale secale) + hairy vetch (Vicia villosa), and medium red clover (Trifolium pretense). Cover crops did gain biomass between samplings, showing that additional growing time between rows was beneficial. While no differences in squash yield were detected, the clover treatment did provide N in rows while conserving it between rows, effectively preventing possible leaching.
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    Legume cover crops in high tunnels: Field evaluation for soil health and controlled environment freezing tolerance
    (2018-02) Perkus, Elizabeth
    This thesis explores legume cover crops as a possible management tool for nitrogen fertility and soil health maintenance in high tunnels. Projects include: 1) a two-year field evaluation of three fall planted cover crop mixes for winter annual production, 2) a controlled environment freezing tolerance study of hairy vetch (Vicia villosa) and red clover (Trifolium pratense) using simulated high tunnel conditions, and 3) a one-year field evaluation of three spring planted cover crop mixes. Cover crop mixes used in projects 1 and 3 consisted of: a) red clover monoculture (T. pratense), b) Austrian winter pea/winter rye 1:1 biculture (Pisum sativum and Secale cereal), and c) hairy vetch/tillage radish/winter rye 4:1:15 mix (V. villosa, Raphanus sativus, and S. cereal). Winter annual legume results show a wide range of biomass nitrogen additions (19.7 to 365.0 kg N ha-1), with no negative impact cash crop yield or soil health measures.
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    Managing nitrogen from manure with a winter rye cover crop: Research dataset
    (2020-02-17) Everett, Leslie A.; Wilson, Melissa L.; Pepin, Randall J.; Coulter, Jeffrey A.; mlw@umn.edu; Wilson, Melissa
    This data is from 19 on-farm studies in Minnesota to evaluate the use of cover crops to trap nutrients from fall manure applications and release them during the growing season for the following cash crop. It includes the amount of above-ground biomass that was produced by the cover crop (CC), soil nitrate in the top 24 inches of soil in plots with and without CC, and yields of the following cash crop in plots with and without CC. There is also data on CC and corn nitrogen uptake. This data was published in a peer-reviewed journal article and is now released.
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    Soil physical, chemical, and microbial community responses to two years of perennial Intermediate Wheatgrass versus annual maize/soybean management systems
    (2023-01) Link, Emma
    Intermediate Wheatgrass (IWG, Thinopyrum intermedium (Host) Barkworth & D.R. Dewey; IWG) is a perennial grain crop with a dense root system which has the potential to facilitate improvements in soil physical structure, fertility, and potentially soil carbon storage. An experiment was established in Rosemount, MN, USA to assess changes in soil physical, chemical, and microbial community responses to IWG system vs. annual corn/soy system management after two growing seasons. This experiment aims to 1) assess soil quality under four systems representing a gradient of perenniality, cropping system diversity and soil disturbance intervals and, 2) investigate relationships between soil microbial community characteristics and desired soil chemical and physical quality outcomes to better understand the mechanisms behind desired outcomes. In the first chapter of this study, we report the agronomic outcomes of the first two years of the experiment and examine how IWG vs. annual crop management affect soil chemical and physical properties over the course of two growing seasons. After two years, we find that the proportion of large water stable soil aggregates at 15-30 cm soil depth increased significantly in IWG but not IWG-alf intercropped systems compared to annual systems. We also find evidence of increased water use deep in the soil profile by IWG systems under drought conditions. In the second chapter, we investigate the responses of soil microbial community composition and potential function to two years of IWG vs. annual management. We find that after two years, fungal community composition varied significantly by cropping system and IWG systems are associated with increased arbuscular mycorrhizal fungi biomass and AMF indicator species. We also find evidence of greater extracellular enzyme activity in IWG systems and an annual system with cover cropping.
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    Winter Camelina Response to Nitrogen for Double Cropping with Maize and Soybean in the Upper Midwest
    (2021-09) Gregg, Stephen
    Winter camelina [Camelina sativa (L.) Crantz] is a potential third crop that could be used to intensify maize [Zea mays L.]-soybean [Glycine max (L.) Merr.] rotations. It is considered a low-input crop, but previous studies have shown that it responds to added N. Yet, no formal fertilization studies have been conducted to determine optimum N levels for conditions in the upper Midwest. A study on camelina response to fertilizer N was conducted from fall 2018 to fall 2020 at three locations in Minnesota. The objectives were to: (i) determine the response of winter camelina to N and (ii) assess the effects of N fertilization strategy (fall-spring split or spring only application) on the productivity and quality of winter camelina. Data collected included grain yield, biomass, grain quality, and yield components. Grain yield and biomass were both affected by N in all locations and years, and both were higher in 2019 compared to 2020; among N rates, grain yield was significantly different, while no differences were found for biomass. Both, oil and protein content in grain were affected by N, with oil content generally declining with N rates increasing beyond 67 or 100 kg N ha-1, depending on location and year. Among yield components, branches and silicles per plant were significantly different among N rates; the former, along with the seed:shell ratio were significantly different in all years and locations. Based on the results of this study, a fertilization rate of 97 kg N ha-1 was found to maximize grain and oil yield of winter camelina in southwest Minnesota. Maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] in the upper Midwest are productive, but decades of these monocultures with winter fallow and late spring planting are in part responsible for loss in agroecological functioning as well as nitrogen (N) pollution in the agricultural communities and downstream. Winter camelina [Camelina sativa (L.) Crantz] is a third crop that could grow during this fallow period, but the environmental impacts of its N requirements are not well known. A study was conducted at three locations in Minnesota to determine the response of winter camelina do N. Five N rates (0, 33, 67, 100, 135 kg N ha-1) and two application timings (spring, and fall-spring split) were used to assess the N use efficiency (NUE) and residual N in winter camelina grown for grain yield from fall 2018 to fall 2020. Results showed higher NUE for fall-spring split application compared to spring only application. The agronomic efficiency (AE), internal efficiency (IE), and nitrogen recovery efficiency (NRE) tended to decrease with increasing N rates; AE generally decreased beyond 67 kg N ha-1 in most instances. Total N uptake ranged from 34 to 176 kg ha-1 across N rates. Residual soil N increased with increasing N rates, especially at the 15 cm depth. Based on declining NUE and increasing residual soil N with increasing N rates, an N rate between 33 to 67 kg N ha-1 could balance an efficient use of fertilizer with less environmental risk of higher N rates. Double cropping with winter camelina is a diversification option for the typical maize-soybean rotation in the upper Midwest, a strategy that promises environmental and economic benefits. Studies on double-cropping maize and soybean with non-fertilized- (Study 1) and nitrogen (N)-fertilized (Study 2) winter camelina were compared to assess the growth and yield, N, water use (WU), and water productivity (WP) of winter camelina in two locations in Minnesota. Study 1 was conducted from 2015–2017 in one location and the Study 2 was conducted from 2018–2020 in two locations, both studies in Minnesota. Yield of winter camelina was as much as six times higher in Study 2 compared to Study 1; averaged across treatments, Study 2 yielded 1157 kg ha-1 compared to 556 kg ha-1 from Study 2. In Study 1, oil and protein content ranged from 26.4 to 27.2% and 19.4 to 27.1% respectively. In Study 2, oil and protein content ranged from 31.7 to 35.9% and 14.9 to 20.8% respectively. Water use tended to follow similar trends between studies. Winter camelina average WU across cropping systems was similar between Study 1 and Study 2 (165 compared to 168 mm). Camelina WP was higher in Study 2 compared to Study 1, and ranged from 0.60 to 0.84 and 0.20 to 0.42 respectively. Fertilizer N was generally found to increase biomass, yield, WU, WP, and residual soil N in winter camelina double cropped with maize and soybean.