Offered Papers Theme A: Efficient Production from Grassland
Description
Tillers in grass swards are subject to size density compensation and this mechanism has been observed to follow the -3/2 self thinning rule. This theory assumes that tiller components (leaf lamina and stems) have a constant geometry as the sward is taller or shorter. In a re examination of this rule (SackvilleHamilton et al., 1995) observed that in grass swards the slope can be different from -3/2 depending on the extremes of defoliation (Hernandez-Garay et al., 1999). Therefore, the dimensionless measure, R (ratio tiller leaf area : volume) was proposed to isolate the tiller geometry component from the tiller size. Guinea grass is the second most sown grass in Brazilian pastures and cv. Aruana has been used successfully in the past ten years in sheep grazing systems. Since this bunch grass presents numerous aerial tillers that contribute to yield, the objective of this paper was to evaluate changes in tiller leaf area and volume on plants subjected to high frequency (simulating a continuous grazing), and low frequency defoliation (simulating an intermittent grazing), under different defoliation stubble heights.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Morphogenetic Characteristics of Panicum Maximum cv. Aruana Subjected to Five Defoliation Stubble Heights and Two Frequencies
Tillers in grass swards are subject to size density compensation and this mechanism has been observed to follow the -3/2 self thinning rule. This theory assumes that tiller components (leaf lamina and stems) have a constant geometry as the sward is taller or shorter. In a re examination of this rule (SackvilleHamilton et al., 1995) observed that in grass swards the slope can be different from -3/2 depending on the extremes of defoliation (Hernandez-Garay et al., 1999). Therefore, the dimensionless measure, R (ratio tiller leaf area : volume) was proposed to isolate the tiller geometry component from the tiller size. Guinea grass is the second most sown grass in Brazilian pastures and cv. Aruana has been used successfully in the past ten years in sheep grazing systems. Since this bunch grass presents numerous aerial tillers that contribute to yield, the objective of this paper was to evaluate changes in tiller leaf area and volume on plants subjected to high frequency (simulating a continuous grazing), and low frequency defoliation (simulating an intermittent grazing), under different defoliation stubble heights.
