Influence of frequency and intensity of clipping on forage yield, crude protein content and digestibility of six Kenyan Range Rasses

The investigation was conducted at two experimental sites on the National Range Station, Kiboko to evaluate forage yield, leaf-to-stem ratio, crown area, tiller number, regrowth height, forage digestibility, and crude protein content of six native range grasses following defoliate at three frequency (3, 6, and 9 week)with three cutting height to leave 5cm, 10cm stuble height. Digitaria macroblephara, panicum maximum and cenchruc ciliaris produced higher forage amounts and tiller number han chloris roxburghiana, Eragrostis superba, and Themeda triandra. The large number of tillers and leaf area produced by digitaria macroblephara, panicum maximum, and cenchrus ciliaris especially at the 6 week harvest frequency, allowed the three grasses to attain a maximum groth rate at an earlier age and recover soon after defoliation at the 3 week harvewt frequency significantly suppressed tillering in all grasses and resulted in significant reductions in forage yield. Furthermore, plants defoliated at the 3 week interval with the 5 cm cutting height produced the lowest forage yield and tiller number. Forage yield, tiller, regrowth height, and crown area for the grasses were highest at the 6 week harvest frequency and lowest at the 3 week haarvest frequency. IN contrst, leaf to stem ratio, crude protein content, and digestibility values were highest at the 3 week harvest frequency and lowest at the 9 week frquency. Crude protein content and digestibility values of the leaf fraction were higher than crude protein cntent and digestibility values of the stem fraction. Furthermore, crude protein content and digestibility showed a decline for all grasses as the interval between defoliations increased. Recommandations for research include studying the responses of grazing animals and native range plants to a grazing plan that utilizes a 42 day defoliation frequency leaving stubble heights of 10 cm to 15cm, and continuing to explore the impacts of defoliation treatments at various phenological stages on native range plants.