Hydrologic properties of grazed perennial swards in semiarid southeastern Kenya

Abstract

Identification of plant resources that persist unde r grazing pressure, support desirable levels of production and at the same time protect the grazing environment is central to sustainable livestock production. This study assessed the infiltration ca pacity and soil loss associated with perennial swar ds subjected to different levels of utilization using s imulated rainfall. The hypothesis was tested that grazed perennial swards have similar hydrologic prop erties and threshold removal levels below which runoff increases markedly. Infiltration capacity f or the perennial swards increased with increasing stubble height before leveling off towards the high est stubble height. A 50% removal of current growth was the upper limit above which runoffs from the sw ards increased rapidly. Aggregate stability, organi c carbon and percent ground plant cover were the most significant attributes that influenced infiltratio n capacity. Panicum maximum and Enteropogon macrostachyus were the most suitable perennial swards with favourable soil physical properties and infilt ration capacities in the study area. The results su pport the existence of a threshold level of sward stubble height for minimizing runoff.