Harvest Techniques Change Annual Warm‐Season Legume Forage Yield and Nutritive Value

Abstract

A gronomy J our n al • Volume 10 0 , I s sue 3 • 2 0 0 8 765 ABSTRACT Comparison among warm-season legume forage trials may not be valid if harvest techniques vary. To address this question, herbage dry matter (DM) yields, branching, crude protein (CP), and fi ber concentrations for nine warm-season annual herbaceous legumes were measured by hand-plucking all leaves and pliable tips or clipping at 7.5-or 15-cm height. Th e experiment was conducted in Texas on a Windthorst fi ne sandy loam over 2 yr. Harvest technique did not aff ect DM yield in 2004, but the hand-plucked harvest technique produced 34 to 39% less forage in 2005 (low rainfall year) compared with the clipped plots. Most entries had greater branching on hand-plucked than on clipped plants (entry by harvest P < 0.05). Crude protein concentration was greater (P < 0.05) and fi ber concentrations lower in the hand-plucked compared with the clipped plants. Th ese results suggest that neither yields nor nutritive values of hand-plucked forage trials examining annual warm-season herbaceous legumes should be compared with clipped forage trials, whereas clipping heights may be less problematic. Results support a careful choice of experiment harvest technique based on the future fi eld-scale harvest method or degree of target herbivore selectivity.

Dry Matter Yield and Nutritive Value of Cowpea and Lablab in the Southern High Plains of the USA

“…The DM yield of these legumes was greater than those values reported under rainfed conditions (7). In this study, lablab and cowpea first cut in 2009 was at 10 weeks (70 DAP) and the second cut was about 7 weeks after first cut (119 DAP), which indicated cowpea may be negatively impacted by multiple harvests (9) or require an extended growing season as reported in other studies (6). Both cowpea cultivars yielded less than the lablab cultivars and there was a difference between cowpea (0.79 and 3.09 Mg/ha for CATJ and I&C, respectively; P < 0.002, SEM = 0.345), but not between lablab cultivars (5.77 and 4.39 Mg/ha for RO and RV, respectively; P > 0.07, SEM = 0.345).…”

“…While cowpea had lower DM yield than lablab, it had greater CP, and NE L concentration, and lower NDF and ADF concentrations than lablab (Table 3). Although cowpea had greater CP, both legumes had > 200 g CP/kg, which is in the upper range of the values reported in other studies (6,9). The NDF concentration was below 350 g/kg in both legumes and was lower than those values reported previously for lablab (3), but ADF and ADL concentrations were in the range of those values reported by for lablab and cowpea (9).…”

“…Plots were sown in a randomized complete block design with four replicates on 11 June 2008 and 1 June 2009. The seeding rates were 43 g/kg/ha for lablabs and I&C and 34 g/kg/ha for CATJ (9), likely due to differences in seed size. Plot size was 7.2 m² with a 0.6‐m separation between plots.…”

Capabilities of Four Novel Warm‐Season Legumes in the Southern Great Plains: Biomass and Forage Quality

“…Muir et al (2008) reported (as crude protein) higher N concentrations, pooled across a series of harvest techniques, for forage cultivars of cowpea and mung bean than we recorded for grain cultivars. The N concentration of shortseason legumes declined during the fi rst half of the season, but increased with the approach of the end of their growing season, as pods developed.…”

“…Annual variations in biomass production by cowpea, mung bean, and soybean in the SGP have been reported (Rao et al, 2005a;Muir et al, 2008). On average, the experimental species did not exceed the level of production generated by soybean, the most commonly used summer legume in the SGP.…”