EFFECTS OF BUFFEL GRASS (Pennisetum ciliare) AND GUINEA GRASS (Megathyrsus maximus) ECOTYPES ON GROUND COVER AND SELECT SOIL PROPERTIES IN SEMI-ARID KENYA

<p><strong>Background:<em> </em></strong>Healthy soils are the key to the sustainability of dryland ecosystems. In semi-arid Kenya, indigenous rangeland grasses have been widely used to rehabilitate degraded lands with the aim of enhancing grass cover as well as enhancing soil quality and other ecosystem services. <strong>Objective: </strong>To assess the effects on ground or soil cover and soil physical and chemical properties of four indigenous grass ecotypes of two common rangeland grass species (<em>Pennisetum. ciliare</em> and <em>Megathyrsus maximus</em>) (Jacq.) B. K. Simon & S. W. L. Jacobs (Syn. <em>Panicum maximum </em>Jacq.), used for fodder and rangeland rehabilitation in semi-arid Kenya, four years after their establishment. <strong>Methodology:<em> </em></strong>A field experiment was carried out in semi-arid southeastern Kenya comprising 4 grass ecotypes namely <em>P. ciliare</em> KLF, <em>P. ciliare</em> MGD, <em>M. maximus</em> ISY and <em>M. maximus</em><em> </em>TVT). These were grown in a rhodic-ferralsol for determination of ground cover attributes and selected soil properties after 4 years. Soil samples were collected up to a depth of 30 cm in the established pastures and analyzed for bulk density, moisture content, pH, soil organic carbon (SOC), Total Nitrogen (TN) and elemental composition [Phosphorus (P), Potassium (K), Calcium (Ca) and Magnesium (Mg)]. Soil micronutrient status [Manganese (Mn), Copper (Cu), Iron (Fe), Zinc (Zn), Sodium (Na)] were also determined. <strong>Results<em>: </em></strong>Inferences were made in comparison with conditions before the establishment of the grasses and comparison among the different grass ecotypes. Overall grass cover ranged between 52 and 85 % among the grass ecotypes, reflecting the importance of indigenous grasses in improving ground cover and rangeland rehabilitation. An improvement in SOC, N, K, Cu, Fe and Zn contents was observed. A decline was however observed in soil P, Mn and Na contents. Divergent responses were observed among the grass ecotypes in terms of soil attributes. <strong>Implications<em>: </em></strong>The growing of indigenous grasses has the capacity and potential to improve soil conditions in the short term (< 5 years) and hence the productivity of semi-arid grasslands. Evidence is provided to guide decisions on the suitability of grasses for improving soil attributes in addition to enhancing forage productivity in semi-arid rangelands. <strong>Conclusion:<em> </em></strong>The grass ecotypes enhanced the ground cover and improved certain soil properties over the 4-year period. In particular, there was an improvement in the soil organic contents, TN, Ca, Mg and K status of the soil. </p>