Defoliation effects on perennial grasses — continuing confusion

Abstract

Although an adequate knowledge of growth patterns and defoliation effects in perennial grasses is a prerequisite for the rational use of veld and pastures for animal production, our knowledge of this subject is far from adequate. The results of various physiological and clipping studies on tropical and subtropical grasses are appraised and their weaknesses in providing information applicable in practical management are indicated. It is suggested that there is a need for increased emphasis on studies of growth patterns and defoliation effects giving priority to (a) defining and evaluating the extrinsic and intrinsic factors affecting differential response to similar defoliation treatments in different circumstances, (b) applying defoliation treatments with a practical bias, and (c) determining actual defoliation patterns under grazing.

Uittreksel

‘n Voldoende kennis van groeipatrone en onthlaringseffekte by meerjarige grassoorte word beskou as ‘n noodsaaklike voorvereiste vir die rasionele gebruik van veld en aangeplame weidings vir veeproduksie. Ons kennis van hierdie onderwerp is egter onvoldoende. Die resultate van verskeie fisiologiese en snystudies op tropiese en subtropiese grassoorte word hier evalueer en die tekortkominge by die praktiese toepassing daarvan in veldbeheer, word aangedui. Dit word voorgestel dat groter nadruk op studies van groei patrone en ontblaringseffekte geplaas moet word, met voorkeur aun (a) bepaling en evaluering van die eksterne en interne, faktore wat die differensiële respons op soorlgelyke ontblaringsbehandelings onder verskillende toestande beïnvloed, (b) toepassing van ontblaringsbehandelings met ‘n praktiese nadruk en (c) bepaling van werklike ontblaringspalrone onder weitoestande.