Canopy Height and Its Relationship with Leaf Area Index and Light Interception of Tropical Grasses

Canopy Height and Its Relationship with Leaf Area Index and Light Interception of Tropical Grasses

Photosynthetic tissues, mainly green leaves, are the major component of forage growth and development. The amount of these tissues in a forage plant is influenced directly by the cutting management, which is based on cutting frequency and stubble height. It is usual to recommend as a management practice to cut (or graze) the forage whenever it reaches a given stubble height. Brougham (1956) stated that, when the forage canopy is intercepting 95% of the photosynthetic active radiation, this is the critical leaf area index (LAI), which means the forage is near its maximum growth rate without shading itself. There is also the optimum LAI, where the forage reaches the maximum point of mass accumulation, indicating time to start grazing or cut. Generally the critical and optimum LAI have close values, but they are not necessarily the same (Brown and Blaser, 1968). This trial evaluated the relationship among canopy height, leaf area index, and light interception in ten different tropical grasses.