Effects of Agroforestry Practices on Soil Properties in the Drylands of Eastern Kenya

Drylands, which are home to about 2 billion people face a myriad of problems among them low land productivity. Agroforestry is one of the land use practices that is perceived to be sustainable with beneficial effects on soil properties. However, the effects of agroforestry practices on soils especially in the drylands have rarely been quantified and studied in details. The study determined the effects of selected agroforestry practices on soil properties in Makueni County of Kenya where agroforestry has been promoted by various organizations. Four soil samples were collected at 0-15cm, 15-30cm, 30-45cm and 45-60cm depths in a zigzag pattern at each 10 x 10m plots established along line transects laid in woodlots established in 2007, 2010 and 2013 and their adjacent parkland and grazing land. Seven randomly selected farms were sampled. The samples were analyzed using laboratory methods for soil nutrients and physical properties. Density of tree species in these established plots were also determined using quadrat technique. Tree density was higher in woodlots followed by grazing area and parkland .Soil samples showed that Soil Organic Carbon and Total Nitrogen were significantly higher in the woodlots than in the parkland and grazing lands ((p≤0.05). Soil Organic Carbon was significantly higher in woodlots established in 2007 than those established in 2013. Phosphorus was significantly higher in cropland compared to woodlots and grazing land. Phosphorus and Potassium were significantly higher at 0-15 cm depth compared to other soil depths. Bulky density was significantly higher with a corresponding lower total porosity in grazing lands than in the woodlots and parklands. The results suggest that different agroforestry practices contribute differently to soil properties. Mixed tree woodlots contributed significantly to improving soil properties and could be considered as a strategy to sustainably restore degraded and infertile soils in the drylands

Exploiting Cropping Management to Improve Agricultural Water Use Efficiency in the Drylands of Eastern Uganda

A remarkable challenge lies in maximizing agricultural water productivity, particularly in the drought prone regions of sub Saharan Africa. It is hypothesized that water use efficiency (WUE) can be increased by selection of appropriate cropping management systems. This study seeks to establish the effects of cropping management on water use efficiency in cassava-sorghum cropping systems in the drylands of eastern Uganda. A randomised complete block design (RCBD) consisting of six treatments: sole cassava, sole sorghum, sole cowpea, cassava + sorghum, cassava + cowpea, and sorghum + cowpea, replicated three times were used. Two tillage practices; mouldboard ploughing (Mb) and, ripping (Rp) were used to assess the effect of tillage. WUE (kg ha-1 mm-1) was calculated as a ratio of yield (kg ha-1) to evapotranspiration (ET) (mm). ET was estimated using the soil water balance. WUE varied significantly (?= 0.05) between cropping systems with the highest observed in cassava (34.38 kg ha-1 mm-1) while the lowest was 3.76 kg ha-1 mm-1 for sorghum. WUE did not differ appreciably in both Mb and Rp tillage practices. Farmers growing sole cassava could use either of the tillage practices. The best yield was recorded in cassava + cowpea cropping system under Mb ploughing and sole sorghum under Rp gave the poorest combined yield (1,676 kg ha-1)

Effect of water conservation measures on soil moisture and maize yield under drought prone agro-ecological zones in Rwanda

This study was conducted to assess agricultural practices for generating maximum maize productivity in drought prone agro-ecological zones. The experiment was conducted in Cyili sub-catchment in Southern Province of Rwanda, which has an irregular rainfall distribution and a prolonged dry season. The experimental design consisted of a randomized design and each treatment was replicated three times. Findings from this study revealed that maize grain yield and yield components, such as plant height, cob diameter and length, number of leaves, 100 grain weight, and yield per plant were highly significantly affected (P  0.05). Supplementary irrigation treatment increased maize yield production to 11,982 kg ha-1. Mulching increased yield significantly to 8089 kg ha-1. Ridges yielded 5937 kg ha-1, and rainfed treatment yielded 4755 kg ha-1 of maize. Based on Pearson's correlation coefficients, grain yield and yield components were positively correlated and statistically significant (p < 0.001) under various water conservation methods. Supplementary irrigation through rainwater harvesting was found to be a more promising option for maize growers to mitigate dry spell and stabilize maize production in rainfall deficient agro-ecological conditions not only in Rwanda, but in sub-Sahara Africa. Keywords: Maize yield, Mulching, Tied ridges, Supplementary irrigatio

Modelling surface runoff using the soil conservation service-curve number method in a drought prone agro-ecological zone in Rwanda

Runoff farming is reported to improve land productivity and crop yields in hot and dry climates. This study was conducted to assess the available rainwater that can be harvested in a conserved catchment in a drought prone agro-ecological zone. The study was carried out in the Cyili sub-catchment, southern province of Rwanda, which has an irregular rainfall pattern and unexploited runoff water. Soil Conservation Service-Curve Number method (SCS-CN), CROPWAT model version 8 and Hazen model with an average daily rainfall data recorded from 1971 to 2016 were applied to estimate the runoff and water requirements in the study area. Findings of the study revealed that more than half rainfall water received in the catchment was lost through runoff (229.8 mm) and effective rainfall was lower (246.9 mm) than the actual crop water requirement for maize (330 mm). The expected seasonal surface runoff volume to be harvested by the farmers was 3008 m3 ha−1 per season and 1.29 × 106 m3 per season for the entire whole sub-catchment (430 ha). Based on Hazen model, the return period of low rainfall (dry spell) event would be expected every 2 years with a 98% probability of occurrence. Cyili sub-catchment has higher potential runoff volume to stabilize the deficit of water demand in the period of short rainy season. This suggests that rainwater harvesting through supplementary irrigation is an option to improve the crop yield in the dry period as well as in the annual dry season. Keywords: Available rainwater, Cyili sub-Catchment, Curve number, Runoff, Rwand

Climate Change and Variability: Farmers’ Perception, Experience and Adaptation Strategies in Makueni County, Kenya

A better understanding of climate change and variability (CCV) from the farmer’s perspective is a key to prioritizing measures to address and prepare for its consequences. A survey involving 150 farmers was thus conducted in Makueni County, Kenya to document farmers’; perception, experience and adaptation strategies to CCV. About 86% of farmers perceived CCV as a major challenge with 53% indicating that significant changes in climate would manifest in 10-20 years. Significant changes in rainfall amounts and distribution had occurred over the years and were rated by 60% of farmers as the frequently experienced aspect of CCV. About 33% of farmers had heard of but not used decision support tools (DST) to inform their agricultural activities. Workshops and seminars were reported by 67% of farmers as principal sources of information on CCV. Additionally, 50% of farmers relied on traditional knowledge for weather prediction. Only 20% of farmers had alternative strategies; agroforestry and growing drought tolerant crops particularly sorghum and cowpea, to minimize effects of CCV. Another 67% of farmers prioritized; terracing, ridging and water harvesting as adaptation strategies to minimize negative effects of CCV. The farmers were thus aware of CCV and through experience, backed with traditional technical knowledge, had gained prerequisite skills for addressing its negative effects. Nevertheless farmers’ agricultural practices could be improved by use of forecasted weather data and application of DST. Consequently enhancing farmers’ preparedness to tackle challenges posed by CCV

Characterization of Kenyan Honeys Based on Their Physicochemical Properties, Botanical and Geographical Origin

Properties and composition of honey are essential in providing information regarding their quality as well as in their differentiation based on production region characteristics, e.g., floral sources. This paper presents physicochemical properties and floral sources (botanical origin) of 21 honey samples obtained from arid and semiarid areas of Kenya, specifically, West Pokot, Baringo, and Kitui Counties. Physicochemical parameters which were analyzed to determine honey quality included moisture content, hydroxymethylfurfural (HMF), diastase activity, free acidity, and electrical conductivity. Values of these parameters were compared with those of the existing local, regional, and international standards for honey. Melissopalynological analysis (pollen analysis) was also carried out to provide information on botanical origin of the honeys. Results showed mean parameter values of moisture, 16.34%; HMF, 23.28 mg/kg; diastase activity, 10.67 Schade units; free acidity, 22.95 meq/kg; and electrical conductivity, 0.40 mS/cm. Free acidity and electrical conductivity values of honey samples obtained from West Pokot were significantly lower than the values of honeys from Baringo and Kitui. Eighteen (18) honey samples had all parameter values within the limits set in the East African, Codex Alimentarius, and the European Union directive standards for honey. Results also showed a total of 29 pollen types in the honey samples analyzed, and Acacia spp. was the predominant pollen type in 4 of the 21 honey samples. Findings of this study showed that Kenyan origin honeys can tap into the existing regional and international markets based on their quality which can be attributed to their botanical origin. Results of this study also suggested that honey producers have undertaken appropriate measures in honey harvesting, processing, handling, and storage. However, there is a need to build capacity of producers whose honey were of unacceptable quality. This would involve training on proper honey production, processing, and handling practices as well establishment of honey collection and processing centres at the local level in order to improve honey quality. This will enhance access to existing honey markets. Conservation of bee floral sources would also be needed to maintain honey quality