Strip Planting a Legume into Warm‐Season Grass Pasture: Defoliation Effects During the Year of Establishment

Abstract

Novel approaches are needed for overcoming barriers to successful association of herbaceous legumes with grasses in warm‐climate pastures and to identify low‐cost, long‐term solutions to the problem of N limitation in low‐input systems. The objective of this experiment was to evaluate defoliation management options during the year of establishment when rhizoma peanut (RP) (Arachis glabrata Benth.) was strip planted into existing bahiagrass (Paspalum notatum Flüggé). Treatments were four defoliation strategies: (i) Control (no defoliation of the planted RP strip and adjacent bahiagrass harvested for hay), (ii) Hay Production (RP strip and adjacent bahiagrass harvested for hay every 28 d), (iii) Simulated Continuous Stocking (pastures grazed weekly), and (iv) Rotational Stocking (pastures grazed every 28 d). Simulated Continuous and Rotational Stocking reduced RP canopy cover and frequency of occurrence. Greatest RP cover during the establishment year was achieved in August with 32 and 29% for the Control and Hay Production treatments compared to 5 and 4% for Simulated Continuous and Rotational Stocking, respectively. Spread of RP was least in Simulated Continuous Stocking. Light penetration to the level of RP in the canopy was not a primary driver of RP response because it was greatest for grazed plots where RP performed poorest. Results show that defoliation management during the establishment year is critical and if pastures are defoliated, hay production is the recommended option.

Seedbed Preparation Techniques and Weed Control Strategies for Strip‐Planting Rhizoma Peanut into Warm‐Season Grass Pastures

“…Similar low levels of spread in the establishment year following strip planting have been reported (Castillo et al, 2013a(Castillo et al, , 2013b and are thought to be due in part to greater emphasis of establishing plants on developing rhizome mass than on aboveground lateral spread. Means were 12, 9, 7, and 0 cm for glyphosate + tillage, tillage only, no-till, and sod removal, respectively.…”

“…Rhizoma peanut canopy cover and frequency were measured following the methodology described by Castillo et al (2013a). In summary, a 1-m 2 quadrat (0.5 × 2 m) was placed in the center of the RP strip at a permanently marked location in each experimental unit, so that canopy cover was estimated in the same area each time.…”

Growth Habit of Rhizoma Peanut Affects Establishment and Spread when Strip Planted in Bahiagrass Pastures

“…3). Additionally, during preparation of the strip for planting, Castillo et al (2013) applied no glyphosate and bahiagrass likely regenerated more rapidly than in the current study, increasing competition to RP. This occurred even though the stubble height for the hayed treatment was 10 cm vs. a target stubble height (bahiagrass component) of 15 cm for grazing.…”

“…The two defoliation treatments were selected based on results from a strip-planting study with Florigraze RP (Castillo et al, 2013). The entries were selected to represent a range in plant growth habit among existing RP cultivars and germplasms.…”

“…At each sampling event, percentage ground cover was estimated in the same 20 squares per quadrat location and averaged to obtain the measure of cover for each experimental unit (Castillo et al, 2013). During the year after planting, ground cover was measured only before the first and last defoliation events.…”