Author: Dennis AshilenjePublisher:
ISBN: 9780438880580
Category : Agronomy
Languages : en
Pages : 213
Book Description
Poor legume persistence reduces performance of grass-legume mixtures. This can be solved by understanding plant community structure changes. A study was conducted from 2015 to 2017 at the University of Wyoming Sheridan Research and Extension Center with the objectives to determine: 1) plant community structure changes and nitrogen (N) use in meadow bromegrass (Bromus riparius Rehm.)—legume mixtures and their role in forage accumulation and nutritive value; 2) effects of N fixation and crop canopy characteristics on forage accumulation and nutritive value of meadow bromegrass-alfalfa ( Medicago sativa L.) mixtures; 3) influence of meadow bromegrass-alfalfa mixtures and N on greenhouse gas emissions and soil microbial biomass; and 4) productivity and economic benefits of grass-legume mixtures. Treatments were alfalfa, sanfoin (Onobrychis viciifolia Scop.), birdsfoot trefoil (Lotus corniculatus L.), and meadow bromegrass or mixtures of them in different ratios. These included 50–50% and 70–30% mixtures of meadow bromegrass with each legume and 50–25–25% mixture of meadow bromegrass with two legumes and 50–16.7–16.7–16.7% mixture of meadow bromegrass, alfalfa, sainfoin, and birdsfoot trefoil. Grass monocultures received 0, 56, and 112 kg N ha−1. Grass-legume mixtures particularly the 50–50% and 70–30% mixture of meadow bromegrass with alfalfa and 50–25–25% mixture of meadow bromegrass, alfalfa, and birdsfoot trefoil had higher forage accumulation, nutritive value, and profitability compared to monocultures. This was associated with low synchrony in species biomass accumulation. Alfalfa seed mass ratio, height within crop canopy, leaf area, and intercepted light were potential measures for predicting forage accumulation and nutritive value. The 70–30% mixture of meadow bromegrass with alfalfa reduced N2O emissions (92 μg N m−2h−1) than alfalfa monocrop (150 μg N m−2h−1). Overall, mixtures with 16.7 to 30% of alfalfa seed mass proportions were buffered against poor sainfoin and birdsfoot trefoil persistence and had enhanced N use, forage productivity, and nutritive value.
