Browsing by Subject "Cover crop"

Now showing 1 - 3 of 3
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    Below-ground plant residues as a source of nitrogen in double-crop forage systems
    (2016-09) Raskin, Daniel
    Double-cropping with forages can increase yields and N-use efficiency over sole-crop systems, but reductions in primary crop yield can limit economic returns. This study assessed whether the combination of high value, forage, early maturing corn varieties, and reduced N inputs constitutes an economically viable, low N-input double crop system for Minnesota. Biomass yield, N uptake, and residual soil N were measured in two double-crop (DC) and one sole-crop (SC) systems at site-years in MN, from 2014 to 2016. In DC treatments, a pea- (Pisum sativum L.) barley (Hordeum vulgare L.) forage bi-culture was double-cropped with early-maturing hybrid (DC-HC) or semidwarf (DC-SD) corn (Zea mays, L.) varieties. In SC treatments, full-season hybrid corn (SC-HC) was planted with no preceding forage. Corn was supplied with 6 N rates (0 to 224 kg N ha-1 for each yield component. Corn yielded less biomass in DC-HC (8.2 Mg ha-1) and DC-SD (1.8 Mg ha-1) treatments yielded compared to SC-HC (16.3 Mg ha-1). Biomass yield deficits lowered corn N demand in DC-HC treatments so that N rates >166 kg N ha-1 did not limit biomass yield in DC-HC treatments, where SC-HC corn was limited by N rate in three of four site-years. Total biomass accumulation was similar between DC-HC and SC-HC treatments when forage bi-culture yielded >7 Mg ha-1. This suggests that double-cropping with high-quality forages may constitute an economically viable low N-input alternative to sole-crop corn production in Minnesota.
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    Evaluating winter-hardiness and developing a screening method for freezing tolerance in the leguminous cover crop Hairy Vetch (Vicia villosa R.)
    (2018-01) Wiering, Nicholas
    Hairy vetch (Vicia villosa R.) is a winter-annual legume that is grown as a cover crop and forage. In addition to reducing soil erosion and suppressing weeds, the species can facilitate enough biological N fixation to supplement or replace the N requirements of maize. Although more winter tolerant than most leguminous winter-annuals, it does not reliably overwinter in temperate environments such as the upper Midwestern United States. Our objectives were to screen a collection of accessions for winter-hardiness and develop a screening method for freezing tolerance in a laboratory setting. To identify winter-hardy germplasm, we evaluated the winter survival of 30 accessions in nine Minnesota environments. Mean percent survival among accessions ranged from 15 to 82% and resembled a bimodal distribution. Due to large variation among and within environments, a method of controlled freezing was developed to supplement field evaluations and advance breeding efforts. No differences in freezing tolerance were found among accessions without prior exposure to cold acclimation. However, large differences were apparent when plants were first grown for two weeks in greenhouse conditions and then cold acclimated for four weeks (3°C; short-day photoperiod). Lethal temperatures were determined from six 24-hr programmed freezing treatments. Programmed cycles began at -3°C and gradually decreased to target temperatures ranging from -13 to -21°C. This method of controlled freezing correlated highly with winter survival in field evaluations (rs = 0.77). This study highlights the value of priori testing of experimental parameters in controlled freezing studies and the importance of validating such methods with field evaluations.
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    Radio News Briefs for a Growing Minnesota, September 12, 1969
    (University of Minnesota, Agricultural Extension Service, 1969-09-12) University of Minnesota, Agricultural Extension Service