Integration of Cool‐Season Annual Legumes and Dairy Manure Compost with Switchgrass

Abstract

Annual cool‐season legumes can contribute forage or green manure to warm‐season grass pastures or biofuel crops but may interfere with subsequent grass development. Arrowleaf clover (Trifolium vesiculosum Savi cv. Yuchi), common vetch (Vicia sativa L.), and button medic [Medicago orbicularis (L.) Bartal cv. Estes] were oversown on 10‐yr‐old switchgrass (Panicum virgatum L.) in north‐central Texas to evaluate dry matter (DM) yield and nutritive value. Legumes were no‐till drilled into a Windthorst fine sandy loam in autumn of 2000 and 2001; plots either received no dairy manure compost or 30 Mg compost ha−1 Forage was harvested when individual legume species reached flowering, when switchgrass regrowth reached boot stage, and at the end of the summer growing season. Switchgrass DM yields (3022–6630 kg ha−1 yr−1) were not reduced by overseeded legumes. Arrowleaf clover had the greatest production among the legume species and yielded more in a monoculture (1762–1923 kg ha−1 yr−1) than with switchgrass (757–814 kg). Cumulative yields increased the second year as a result of legumes, compost, and combinations of the two. Compost increased phosphorus concentrations in both the grass and legumes, but not crude protein or acid detergent fiber concentrations. Cool‐season annual legumes may be beneficial in switchgrass forage and biofuel systems, especially in combination with manure compost.

Forage Attributes and Animal Performance from Native Grass Inter‐Seeded with Red Clover

“…Several species of cool‐season legume were successfully established in mature upland SG stands by drilling (Blanchet et al, 1995) and frost‐seeding (Gettle et al, 1996) and in both cases, had substantial effects on stand yield (George et al, 1995; Gettle et al, 1996). Similarly, in Texas, lowland SG yield and sward forage quality were improved by overseeding with cool‐season legumes (Bow et al, 2008). In another study conducted in the southern Great Plains, lowland SG yields were not affected by cool‐season legumes, but total sward yield was increased (Butler et al, 2013).…”

Legume Addition to Perennial Warm‐Season Grass Swards Increases Harvested Biomass

“…Legume addition cannot reduce weed pressure during the establishment year when the issue is of greatest concern (McLaughlin and Kszos, 2005). The simultaneous establishment of warm-season grasses and legumes has been shown to be ineffective because of the rapid emergence and high competitive ability of the legumes (Bow et al, 2008). In the cropping system evaluated in this study, clover addition did not reduce weed pressure during its establishment year (second year of growth for the warmseason grasses) but was effective in reducing weed cover once established.…”

“…Legume addition to cropping systems typically results in atmospheric N fixation, which should reduce fertilizer requirements to maintain a level of productivity otherwise realized with inorganic fertilizer application. The production of a legume and warmseason grass mixture might also increase farmer flexibility because the legume crop can be harvested and used as highquality animal feed (Bow et al, 2008). The production of a legume and warmseason grass mixture might also increase farmer flexibility because the legume crop can be harvested and used as highquality animal feed (Bow et al, 2008).…”

“…Reduced inorganic fertilizer should increase profitability and reduce N 2 O emissions (Rochette and Janzen, 2005). The production of a legume and warmseason grass mixture might also increase farmer flexibility because the legume crop can be harvested and used as highquality animal feed (Bow et al, 2008).…”

Establishment of reed canary grass with perennial legumes or barley and different fertilization treatments: effects on yield, botanical composition and nitrogen fixation

“…However, Tuvesson () did not use the delayed harvest method and the proportions of the species were not reported, so the findings cannot be directly compared with our results. However, that study along with successful intercropping of switchgrass with legumes for summer harvests (Springer et al ., ; Bow et al ., ) imply that RCG/legume intercrops might be beneficial as feedstock for biogas or ethanol production. In another study, by Jasinskas et al .…”