Water use efficiency of six rangeland grasses under varied soil moisture content levels in the arid Tana River County, Kenya

This study evaluated water use efficiency (WUE) of six range grasses, namely; Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense grown at 80, 50, 30% field capacity (FC) soil moisture contents and rainfed treatment which represented water deficit conditions. The changes in soil moisture content were measured by Gypsum Block which aided in determining the irrigation schedules. The grasses demonstrated varied levels of WUE which was evaluated by amount of biomass productivity in relation to evapotranspired water during the growing period. The three soil moisture content treatments had higher water use efficiency than rainfed conditions. There was a declining trend in WUE with grass species maturity where S. sudanense had higher WUE at 8, 10 and 12th weeks (> 15 kg DM ha-1 mm-) in all the treatments followed by C. gayana and E. macrostachyus and were significantly (p<0.05) different from E. superba, C. ciliaris and C. roxburghiana which had WUE less than 10 among the six grass species. The 30% FC soil moisture content had higher WUE at all the phenological stages for S. sudanense, C. gayana and E. macrostachyus compared to 80, 50% FC and rainfed with all having WUE greater than 20 kg DM ha-1 mm-1. These three species are recommended for irrigated pasture establishment in semi-arid lands where water supply uncertainties exist, owing to their high water use efficiency under lower soil moisture levels.Key words: Water use efficiency (WUE), water stress tolerance, range grasses, pasture irrigation, water deficit, Kenya

Estimating Rice Yield under Changing Weather Conditions in Kenya Using CERES Rice Model

Effects of change in weather conditions on the yields of Basmati 370 and IR 2793-80-1 cultivated under System of Rice Intensification (SRI) in Mwea and Western Kenya irrigation schemes were assessed through sensitivity analysis using the Ceres rice model v 4.5 of the DSSAT modeling system. Genetic coefficients were determined using 2010 experimental data. The model was validated using rice growth and development data during the 2011 cropping season. Two SRI farmers were selected randomly from each irrigation scheme and their farms were used as research fields. Daily maximum and minimum temperatures and precipitation were collected from the weather station in each of the irrigation schemes while daily solar radiation was generated using weatherman in the DSSAT shell. The study revealed that increase in both maximum and minimum temperatures affects Basmati 370 and IR 2793-80-1 grain yield under SRI. Increase in atmospheric CO2 concentration led to an increase in grain yield for both Basmati and IR 2793-80-1 under SRI and increase in solar radiation also had an increasing impact on both Basmati 370 and IR 2793-80-1 grain yield. The results of the study therefore show that weather conditions in Kenya affect rice yield under SRI and should be taken into consideration to improve food security

Enhancing Production While Saving Water Through the System of Rice Intensification (Sri) in Kenya’s Irrigation Schemes

Water available for irrigation has drastically reduced in recent years, especially in agricultural areas of Kenya, due to climate variability as well as unprecedented expansion of irrigation projects. As a result, any intervention that can save water, while also increasing crop yields and quality of produce is a welcome intervention. This is where the System of Rice Intensification (SRI) comes in. SRI is a technology that changes how rice is grown in paddies, and which increases yields. SRI involves among its practices, the alternate wetting and drying of paddies, wider spacing and transplanting only one seedling per hill as well as mechanical weeding. SRI was introduced in Kenya at the Mwea Irrigation Scheme in 2009, through research, awareness creation and training of various cadres of stakeholders, especially farmers. Starting with just two adopter farmers, adoption of SRI steadily rose to cover five irrigation schemes in Kenya, namely, Mwea, Ahero, Budalangi, West Kano and South West Kano. By December 2017, over 10,000 rice farmers had adopted SRI in the five schemes. The high adoption was driven by positive results. In Kenya, SRI increased rice yields by between 20% -100% depending on variety, while water savings of 25%-33% have been recorded under controlled experimentation. Research on SRI has been conducted by PhD and masters students, thus validating the technology scientifically, showing increased yields and water-saving factors. The effects of SRI on mosquito breeding showed that all mosquito larvae died in paddies under SRI, while they remained alive and multiplied in conventional flooded paddies, showing the technology holds promise for reducing malaria prevalence. Furthermore, SRI produces a harder, better grain which has superior qualities on milling and marketing. Indeed, SRI is a green technology which holds promise for food security, water savings, health and environmental benefits and improved productivity of rice in Africa

Iron production in second millennium AD pastoralist contexts on the Laikipia Plateau, Kenya

Iron has played an important role within East African pastoralist societies for many hundreds of years, yet the means by which iron was produced or obtained by these communities has not been thoroughly documented. The bulk of our understanding is presently based on a limited number of ethnographic and artefact studies, which have tended to focus on the functional and symbolic nature of iron objects themselves. We argue that the research presented here provides the first opportunity to add to this narrow knowledge base by reconstructing the iron production technologies of pastoralist communities in Laikipia, Kenya, using an archaeometallurgical approach. Seven furnaces and one iron-production refuse area were excavated at two discrete workshop sites in Laikipia, central Kenya, that date to the second half of the second millennium AD. The recovered archaeometallurgical materials were analysed using optical microscopy, SEM-EDS and ED-XRF. These techniques revealed that the smelting technologies in question were complex and sophisticated and that they utilised titania-rich black sands and lime-rich charcoal. Whereas the technical approach and raw materials were found to be similar at both sites studied, there was striking stylistic variation in furnace design for no apparent functional reason, which might suggest nuanced differences in the socio-cultural affiliations of the smelters who worked at these sites. This paper explores some of the possible reasons for these differences. In particular, by integrating archaeological data with existing ethnographic and ethnohistoric research from the region, we discuss the technological choices of the smelters and what this might tell us about their identities, as well as considering how future research should best be targeted in order to develop a greater understanding of the organisation of production within pastoralist central Kenya