Description
Understanding relationships among canopy light interception (LI), canopy height and structure, and leaf area index (LAI) informs management decisions and can improve efficiency of forage-livestock systems. In a long-term experiment in Florida, USA, we assessed the LI, LAI and sward height relationships of rhizoma peanut (Arachis glabrata Benth., RP)-bahiagrass (Paspalum notatum Flügge) mixed swards compared with bahiagrass monoculture to determine whether changes in canopy structure affect herbage accumulation (HA) rate due to changes in radiation use. Treatments were arranged in a semi-factorial, split-plot design (r=4). Bahiagrass monoculture and bahiagrass-RP mixtures were whole-plot treatments. Sub-plot treatments were an undefoliated control, forage clipped to 5 cm when LAI > 3, and forage clipped to 5 cm when LAI > 3 and fertilized immediately after with 20 kg N ha-1. During 2021, LI, LAI and canopy height were measured weekly using a LiCOR LAI-2200 and a rising plate meter (platemeters g1000), respectively. The proportion of bahiagrass and RP in total herbage mass was determined for each treatment in July 2021. Herbage accumulation rate was calculated as HA during the regrowth period divided by days between clipping events. The relationship of LI and LAI was assessed with a negative exponential model. Relationships of cumulative LAI and sward height and days after clipping were determined using regression analysis. Incorporating RP into bahiagrass increased LI at shorter sward height compared with bahiagrass monoculture due to a greater LAI mm-1 of sward height (190-220 vs. 150-160 mm). Fertilized mixtures achieved LAI95 faster than bahiagrass monoculture, however, changes in mixture canopy structure did not result in greater radiation-use efficiency compared with fertilized bahiagrass monoculture. Herbage accumulation rate decreased for mixtures containing more than 30% RP. Application of this information can improve the efficiency of grazing systems and maximize HA of bahiagrass-RP mixtures, either under rotational or continuous stocking.
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Canopy Characteristics and Growth Rate of Bahiagrass Monoculture and Mixtures with Rhizoma Peanut
Understanding relationships among canopy light interception (LI), canopy height and structure, and leaf area index (LAI) informs management decisions and can improve efficiency of forage-livestock systems. In a long-term experiment in Florida, USA, we assessed the LI, LAI and sward height relationships of rhizoma peanut (Arachis glabrata Benth., RP)-bahiagrass (Paspalum notatum Flügge) mixed swards compared with bahiagrass monoculture to determine whether changes in canopy structure affect herbage accumulation (HA) rate due to changes in radiation use. Treatments were arranged in a semi-factorial, split-plot design (r=4). Bahiagrass monoculture and bahiagrass-RP mixtures were whole-plot treatments. Sub-plot treatments were an undefoliated control, forage clipped to 5 cm when LAI > 3, and forage clipped to 5 cm when LAI > 3 and fertilized immediately after with 20 kg N ha-1. During 2021, LI, LAI and canopy height were measured weekly using a LiCOR LAI-2200 and a rising plate meter (platemeters g1000), respectively. The proportion of bahiagrass and RP in total herbage mass was determined for each treatment in July 2021. Herbage accumulation rate was calculated as HA during the regrowth period divided by days between clipping events. The relationship of LI and LAI was assessed with a negative exponential model. Relationships of cumulative LAI and sward height and days after clipping were determined using regression analysis. Incorporating RP into bahiagrass increased LI at shorter sward height compared with bahiagrass monoculture due to a greater LAI mm-1 of sward height (190-220 vs. 150-160 mm). Fertilized mixtures achieved LAI95 faster than bahiagrass monoculture, however, changes in mixture canopy structure did not result in greater radiation-use efficiency compared with fertilized bahiagrass monoculture. Herbage accumulation rate decreased for mixtures containing more than 30% RP. Application of this information can improve the efficiency of grazing systems and maximize HA of bahiagrass-RP mixtures, either under rotational or continuous stocking.
