Browsing by Author "Omondi, E."

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Conservation agriculture effects on earthworm populations in western Kenya and eastern Uganda soils.
(RUFORUM, 2014-07-25) Oluko, Patrick Samba; Norton, J.; Okalebo, J.R.; Omondi, E.; N'getich, W.; Shikuku, D.S.; Okeyo, J.M.; Odhiambo, J.A.; Norton, U.; Ashilenje, D.; Wangoli, J.W.
Conventional cultivation in Western Kenya and Eastern Uganda over the years has resulted into decline in soil quality and food crop production. Studying soil biodiversity under Conservation Agriculture production systems (CAPS) will help understand dynamics of soil structure and the replenishment of nutrients. Population of soil invertebrates and soil pH by Nitrogen application (+N and -N) were studied under maize (Zea mays), beans (Phaseolus vulgaris) and Mucuna (Mucuna pruriens) crops: 3 tillage systems; (1) No-Till (NT), (2) Conventional Tilage (CT), (3) Minimum Tillage (MT); 3 cropping systems (1) Strip-cropping (ROT 2), (2) Intercropping with Mucuna riley, (3) continuous maize-beans intercropping. A 20 g soil sample (0-20 cm depth) was used for macrofauna analysis at vegetative stage. Tillage affected macrofauna population densities differently with the order of highest to lowest; MT < NT < CT. Macrofauna numbers and quantity and quality of residue returned into soil under Mucuna cover crop correlated positively. N-application improved earthworm population in a strip-cropping under MT. Mucuna strip and +N recording the highest number of macrofauna (earthworms, millipedes, centipedes) followed by beans (+N) and maize (+N). A negative correlation was realized between soil pH and earthworm population, with population significantly (P<0.001) reducing with soil pH (<5.00). Residue incorporation under MT was decomposed by the increased number of soil macrofauna under Mucuna cover crop plots resulting into improved soil quality. CAPS involving MT and ROT 2 aids in arresting and reversing downward spiral of resource degradation, decreasing cultivation costs and making agriculture more resource-use-efficient, competitive and sustainable.
Conservation agriculture for smallholder farms in eastern Uganda and western Kenya
(2012) Norton, James; Omondi, E.; Norton, U.; Ngosia, D.S.; Odhiambo, J.A.; Okeyo, J.; Okalebo, J.R.; Oluko, Patrick Samba
Soil quality and crop yield parameters resulting from conservation agriculture practices were evaluated in on-station and on-farm studies established in two highland sites and two lowland sites in the Mount Elgon region of western Kenya and eastern Uganda. Each of the four study areas consists of an on-station and four on-farm sites, each with of three tillage practices (conventional moldboard, no-till, and minimum till); two levels of nitrogen fertilizer (60 Kg N Ha-1 and none); and three cropping systems (traditional maize-beans intercropping, maize intercropped with a bean-Mucuna [Mucuna pruriens] relay, and strip intercropping with maize, beans, and Mucuna in rotation planted in four-row strips) in a factorial design with nine treatments. First and second year results of soil organic matter analyses and crop yields indicate that reduced tillage combined with adding the cover crop to the rotation has begun to improve soil quality and has not negatively impacted yields. Some cooperating farmers have noted improved maize yields following Mucuna and are eager to scale up reduced-tillage and cover crop treatments.
Heavy metal distribution in soils of some urban and peri-urban horticultural farms in Botswana
(RUFORUM, 2014-07) Obuseng, L.C.; Meulenberg, F. Pule; Mubyana, T. John; Mpuisang, T.; Agbenin, J.; Oluko, Patrick Samba; Norton, J.; Okalebo, J.R.; Omondi, E.; N’getich, W.; Shikuku, D.S.; Okeyo, J.M.; Odhiambo, J.A.; Norton, U.; Ashilenje, D.; Wangoli, J.W.; Otiende, Verrah Akinyi; Mwanga, E.F.; Gitau, A.N.; Christiane, T.; Ernest, M.; Manuel, Joana; Matusse, Joaquim; Pimentel, Andréa Eloisa Bueno; Hess, S.; Hatab, A.A.; Da Silva, L.M.; Boly, H.; Glym, C.; Chibinga, O.C.; Musimba, N.M.; Nyangito, M.; Simbaya, J.; Elhag, M. Muna; Sulieman, M. Hussein
Despite the fact that there is high usage of agrochemicals and use of urban waste water for irrigation, the concentration of potentially toxic metals in urban and peri-urban agriculture (UPA) farms has not been widely investigated in Botswana. The study focused on quantitative assessment of potentially toxic metals in horticultural production under UPA. Crops which are cultivated at the selected study sites include spinach (Spinacia oleracea L.), rape (Brassica rapa var. rapa.), cabbage (Brassica oleracea var. capitata), green pepper (Capsicum annum) and tomato (Solanum lycopersicum). Two farms from areas surrounding Gaborone namely Glenn Valley and Mmankgodi, were sampled for the determination of total heavy metals concentration in soils. In Glenn Valley secondary treated waste water is used for irrigation while in Mmankgodi underground water is used. Four soil profile pits were dug at each farm and soil samples of 20 cm increment were collected from the surface to a depth of 100 cm. Results showed concentration ranges of 0.12 - 1.22 mg/ L for Cr, 0.09 - 0.47 mg/L for Cu and from 0.01 - 0.24 mg/L for Pb. Copper and Chromium were above threshold levels for crop production (Cu 0.2 mg/L, Cr 0.1 mg/L) as per Food and Agriculture (FAO) standards and Botswana Bureau of Standards (BOBs), while Pb concentration was significantly higher at Glenn Valley than Mmankgodi, but below recommended threshold levels of 2.0 mg/L. These results are a wake-up call that policies on the use of sewage effluent and agrochemicals should be enforced.