Linking Management, Environment and Morphogenetic and Structural Components of a Sward for Simulating Tiller Density Dynamics in Bahiagrass (Paspalum notatum)

Abstract

Abstract:A model which describes tiller density dynamics in bahiagrass (Paspalum notatum Flügge) swards has been developed. The model incorporates interrelationships between various morphogenetic and structural components of the sward and uses the inverse of the self-thinning rule as the standard relationship between tiller density and tiller weight (a density-size equilibrium) toward which tiller density progressively changes over time under varying nitrogen (N) rates, air temperature and season. Water and nutrient limitations were not considered except partial consideration of N. The model was calibrated against data from swards subjected to different N rates and cutting intensities, and further validated against data from a grazed sward and swards under different cutting intensities. As the calibration and validation results were satisfactory, the model was used as a tool to investigate the responses of tiller density to various combinations of defoliation frequencies and intensities. Simulations identified defoliation regimes required for stabilizing tiller density at an arbitrary target level, i.e., sustainable use of the sward. For example, the model predicted that tiller density can be maintained at a medium level of about 4000 m −2 under conditions ranging from weekly cuttings to an 8 cm height to 8-weekly cuttings to 4 cm. More intense defoliation is needed for higher target tiller density and vice versa.

Grazing height management does not change the persistence pathway of Andropogon lateralis in a natural pasture

“…It is worth noting that the strategy used by A. lateralis plants was different from the strategy observed in most perennial grasses of warm season, which show high rates of tiller appearance during the summer period, to keep their population stable (Caminha et al, 2010;Sbrissia et al, 2010). Furthermore, grasses of the genus Paspalum are also able to maintain stable populations by high-survival rates practically throughout the year (Hirata, 2015), which bears similarities with the results obtained in the present study on A. lateralis.…”

Defoliation, Shoot Plasticity, Sward Structure and Herbage Utilization in Pasture: Review of the Underlying Ecophysiological Processes

“…Modeling methodologies have been developped during recent years. Several descriptive morphological models have been proposed [29,84,119,121,122]. Additionally, several structure-function virtual modeling approaches have been proposed more recently [106,[123][124][125][126][127].…”

Seasonal and interannual variations in feeding station behavior of cattle: effects of sward and meteorological conditions

“…Alternatively, N fertilizer has been reported to be effective for increasing sward height and DMD simultaneously in a grass pasture (Boval et al, 2002;Hirata et al, 2006), through the positive effect on the mass and length of leaves (Boval et al, 2002;Hirata, 2004). However, application of N cannot be justified only on the basis of the feeding station behavior and daily herbage intake of animals.…”