Socioeconomic constraints to sustainable cocoyam production in the Lake Victoria Crescent

Cocoyam production has the potential of significantly improving the food security status and income levels of farmers in the Lake Victoria region. The study covered various areas of the three East African states, Kenya, Uganda and Tanzania as follows: Kisumu, Kakamega and Siaya districts in Kenya; Bukoba in Tanzania; and Mukono, Wakiso and Kampala in Uganda. Structured questionnaires were used to collect data from a total of 283 respondents. Results showed that farmers had an adequate level of education that enabled them utilize cocoyam production technologies. However, land scarcity was the major factor limiting cocoyam cultivation. This was attributed to the fact that cocoyam cultivation was restricted to wetlands, which was already a limited resource in the region. Other factors such as diseases, weeds, pests, scarcity of labour, unavailability of extension services and planting material and improved varieties, among others influenced the production of the crop. Research and development agencies in the study area need to develop appropriate cocoyam production technologies to mitigate existing constraintsKey words: Cocoyam production, social and economic constraints, Lake Victoria region

Growth and development of wetland-grown taro under different plant populations and seedbed types in Uganda

Taro [ Colocasia esculenta (L.) Schott] is a member of the Araceace family that is a staple food for many people in developing countries in Africa, Asia and the Pacific Islands. It is widely grown in Uganda but the extent of its production and consumption is not known, partly because it has been ignored as legitimate crop for research and development (R&D), and it is managed outside the conventional agricultural production, marketing and economic channels. Therefore, there is limited information on many aspects of taro, including agronomic practices. In order obtain data that can support improved and sustainable taro production, a field trial was conducted over two cropping seasons at Kabanyolo in central Uganda, to determine the effect of three taro plant populations (10,000, 17,760 and 40,000 pph) and two seedbed types (flat and ridged seedbed) on growth and yield of taro. The treatments were arranged in a split - split - plots design, with three replications. Seedbed type was in the main plot and plant populations in the sub-plots. These were further split to accommodate five sampling dates for plant growth. Each experimental subplot measured 6 m x 6 m and contained 36, 64 and 144 experimental plants, respectively. During a 5-month growth period, leaf area index (LAI) and corm yield were significantly (P < 0.05) higher in closely spaced plants (high plant population). Seedbed type had no (P>0.05) effect on taro growth and yield. However, using high plant population may not be recommended because of the enormous amount of planting material that would be needed. From this study, a moderately wide spacing of 0.75 m x 0.75 m which produced an acceptable yield of 5.5 - 6.8 t ha-1 would be recommended.Le Taro [ Colocasia esculenta (L.) Schott] est membre de la famille Araceace qui est un aliment de base pour un grand nombre de personnes dans les pays en développement en Afrique, Asie et Pacifique. Le Taro est largement cultivé dans bon nombre de zones humides en Ouganda, mais comme une activité de production informel gérée sans appui de la recherche et la vulgarisation agricole. Par conséquent, il y a peu de renseignements sur de nombreux aspects de Taro, y compris les pratiques agronomiques. Afin d’obtenir des données qui peuvent soutenir une production durable et améliorée de Taro, un essai au champ avait été établi au centre de l’Ouganda en deux saisons culturales afin de déterminer l’effet des trois populations de plantes de Taro (10.000 ; 17.760 et 40.000 plants par hectare (pph) et deux types de bandes de plantation (plate et rugueuse) sur la croissance et le rendement de Taro. Les traitements avaient été organisées en split - split - plot dans un modèle en blocs completement randomisés avec trois réplications. La bande de sémis type était dans la parcelle principale qui avait été divisée pour recevoir trois populations végétales et celles-ci étaient en plus divisées pour recevoir cinq dates de plantation échantillonnées pour la croissance des plantes. Pendant une période de croissance de 5 mois, l’index de surface de feuilles (LAI) et le rendement en bulbe étaient significativement plus élevés (P < 0,05) dans les plantes étroitement espacées (plante à population dense), tandis que le type de bande de plantation n’avait pas affecté la croissance et rendement de Taro. Toutefois, une densité de plantation élevée pourrait ne pas être recommandée en raison de la quantité énorme de materiel de plantation qui serait nécessaire en plus de rendement net réduite par unité de matériel de plantation. De cette étude, un espacement modérément large de 0,75 m x 0,75 m qui avait produit un rendement acceptable de 5,5 - 6,8 tonnes par hectare pourrait être recommandé. Le choix du type de bande de plantation à être utilisée pour la production de Taro doit dépendre de la topographie et du degré de l’humidité de la zone de production

Micro-Dosing of Lime, Phosphorus and Nitrogen Fertilizers Effect on Maize Performance on an Acid Soil in Kenya

High cost of inorganic fertilizers and lime has precluded their use by smallholder farmers to remedy the problem of soil acidity and infertility in Kenya. To address the problem, we tested a precision technique referred to as micro-dosing, which involves application of small, affordable quantities of inorganic inputs on an acid soil in Busia County, Kenya. Experimental treatments were N-fertilizer (0 and 37.5 kg N ha-1), P-fertilizer (0 and 13 kg P ha-1) and lime (0, 0.77 and 1.55 tons lime ha-1). 37.5 kg N and 13 kg P ha-1 are 50% of the recommended fertilizer rates for maize production in Kenya while 0.77 and 1.55 tons lime ha-1 are 25 and 50% of the actual requirement. Soil chemical changes, maize grain yield and nutrient recovery were determined. Lime and P-fertilizer significantly affected only the top-soil pH, Ca, Mg and available P, while the effects of N-fertilizer were evident on both top- and sub-soil N likely due to its faster mobility than P and lime. Grain P-fertilizer recovery efficiencies were 14 and 16-27% due to 13 kg P and 13 kg P + 0.77-1.55 tons lime ha-1, respectively. N-fertilizer recovery efficiencies were 37 and 42-45% due to 37.5 kg N and 37.5 kg N + 0.77-1.55 tons lime ha-1, respectively. Fertilizers applied to supply 37.5 kg N, 13 kg P and 0.77-1.55 tons lime ha-1 increased grain yield above the control by 134, 39 and 12-22%, respectively, therefore micro-dosing of these inputs can increase maize production on Kenyan acid soils