Evaluating performance of range grasses under different micro-catchments and financial returns from reseeding in Southern Kenya

Abstract

A study was carried out in the southern rangelands of Kenya to test the effect of two microcatchments - ox-furrows and crescent shaped pits (Kiboko range pits) on the performance and competitive interactions of mixtures and monocultures of four range grasses (Cenchrus ciliaris, Chloris roxburghiana, Enteropogon macrostachyus and Eragrostis superba). The study also evaluated the economic returns from the two reseeding approaches. A questionnaire survey was also administered to capture general issues regarding reseeding in the study area. On-farm and on-station seed samples for the four grasses were collected to compare their germination capacity. The germination tests were done in the laboratory at room temperature on standard petri-dishes over a period of 14 days. The effect of micro-catchments on the performance and competitive interactions among the grass species was tested in a split plot experimental design. The main-plot (27m x 6m) was the type of micro-catchment while the sub-plot (2.5m x 2.5m) was the species type either as mixtures or monocultures. The grasses were sown by hand at a seeding rate of 5kg per hectare. A quadrat (O.5m x O.5m) placed in the middle of each sub-plot was used to monitor the following plant parameters: percent cover, plant density, tiller density, leaf density, plant height, aboveground biomass production and seed production. Data were collected at six, nine, twelve and sixteen weeks post sowing. An economic analysis of the two reseeding enterprises was done by computing the benefit-cost ratio (BCR) and internal rate of return (lRR). All costs, from the time of land preparation to hay harvesting were recorded. Hay harvested from the experimental plot was valued at prevailing market price and used as a proxy to the benefits accrued from reseeding. The germination percent among the grass species was significantly different (p~O.05). Enteropogon macrostachyus had the highest percent germination (98.7%) after 14 days. The germination percent for the other three grasses were: C. roxburghiana (52.5%), E. superba (44.2%) and C. ciliaris (41.1 %). The germination percent between on-farm and on-station grass seeds was significantly different (p:S0.05). In terms of species, only C ciliaris showed a significant difference between on-farm and on-station grass seeds. However, the storage duration did not have a significant effect on the germination capacity of the grass seeds. There was a significant difference (p:s0.05) between ox-furrows and Kiboko range pits in percent cover and plant density (plants/rrr'). However, the difference was not significant between the two microcatchments in tiller density, leaf density, plant height, aboveground biomass production and seed production. Nevertheless, Kiboko range pits performed slightly better than ox-furrows in all the measured parameters. Among the grass species, there was a significant difference only in percent cover and plant density. Cenchrus ciliaris as a rnonoculture and in mixtures outperformed the other four grasses. The BCR indicated that the reseeding approaches are viable undertakings. Kiboko range pits yielded a BCR of2.5 and ox-furrows 2.6. Among the monocultures, C ciliaris gave the highest benefits with a BCR of 3.7 and 3.2 under ox-furrows and Kiboko range pits, respectively. The least beneficial grass species was E. superba with a BCR of 1.0 and 1.3 in the ox-furrows and Kiboko range pits, respectively. The IRR for ox-furrows and Kiboko range pits were 22.6% and 23.6% respectively, which were higher than the lending rate of 14.76% for 2009. In conclusion, on-farm grass seed production should be promoted in the study area to meet the rising demand for grass seeds, the farmer has the option of using either Kiboko range pits or OXfurrows as types of micro-catchments for reseeding purposes since both are economically viable, and C ciliaris is the superior grass species and therefore should be promoted as the species of choice for reseeding in the southern rangelands of Kenya.