Browsing by Subject "Symbiotic nitrogen fixation"

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    Effects of cold temperatures and high tunnel environments on symbiotic nitrogen fixation and growth of winter annual legume cover crops
    (2019-03) Thurston, Charlotte
    We investigated the effect of Upper Midwest winter temperatures on nitrogen contributions of winter annual legume crops via productivity and symbiotic nitrogen fixation (SNF). Projects included: 1) a controlled environment study of growth, nodulation, and SNF in crimson clover (Trifolium incarnatum), Austrian winter pea (Pisum sativum), and hairy vetch (Vicia villosa), and 2) a high tunnel evaluation of four cover crop mixes for productivity, nodulation, and SNF. High tunnel treatments included: a) crimson clover monoculture (T. incarnatum), b) red clover monoculture (Trifolium pratense), c) Austrian winter pea/winter rye biculture (Pisum sativum and Secale cereale), and c) hairy vetch/tillage radish/winter rye mix (V. villosa, Raphanus sativus, and S. cereale). Legume biomass, nodulation, and SNF were limited below 10°C. In high tunnels, lowest biomass and nodulation occurred in mid-winter and lowest SNF in early spring. Delayed spring recovery of SNF suggested that later winter annual cover crop termination could increase nitrogen contributions.