Estimating Prosopis pod production in the drylands of Magadi in Kajiado, Kenya

Abstract

Prosopis juliflora was introduced in Baringo County in the Rift valley, Kenya as a shrub species to rehabilitate the denuded dry lands. It became invasive and spread to other pastoralist areas in Kenya, including Magadi region thereby competing and replacing other vegetation types. Past research has however shown that its pods have proven qualities for use as animal feedstuff. This study was undertaken with the objective of establishing whether Prosopis juliflora pods in the drylands of Magadi area in Kajiado County was in sufficient quantities for production of animal feeds. Pods were collected and weighed once a week in randomly selected and fenced 30 x 30-meter plots in the Nguruman escarpment and the Olkiramatian floodplains. Three categories of plots based on plant density were marked out as dense, moderate and sparse respectively. Half of the dense plots had their Prosopis trees pruned and thinned to allow spacing of five meters (managed dense). Weekly collection and weighing of pods was carried out for a period of ten months including one wet season and two dry seasons. The managed dense, unmanaged dense, moderate and sparse plots yielded 44.3 tonnes per hectare (tha-1,) 24.5 tha-1, 15.4 tha-1 and 1.3 tha-1 in Nguruman escarpment and 9.3 tha-1, 17.6 tha-1, 1.5 tha-1 and 0.2 tha-1 in the Olkiramatian floodplains respectively. The management practice of pruning and spacing increased pod yield production in the well-watered escarpment landscape. The lowest and highest pod yields were recorded during the dry season and the rainy season respectively. The results showed that the dense unmanaged plots in the lowland landscapes had higher pod yields when compared to the managed dense plots in the escarpment landscape. Variation in pod yields was analyzed using Genstat 14th edition. The results from this study found that the managed Prosopis stands located in the escarpment