Browsing by Author "Muriithi, C."
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Item Effects of Fertilizer Phosphorus and Crop Residues on Crop Biomass, Soil Carbon and Phosphorus in a Ten-year Field Trial in Semi-Arid Kenya(2013) Kihanda, F.M.; Warren, G.P.; Muriithi, C.; Kenya Agricultural Research Institute, Embu Regional Research CentreThe possibility of improving soil fertility with a high "recapitalization" dose of phosphorus (P) in conjunction with crop residues was assessed in a severely P-deficient soil. The experiment comprised three treatments cropped to sorghum (sorghum bicolor): crop residues returned to the plot, (ii) residues returned plus additional residues, (iii) residues removed and added to treatment (ii); and bare and grass fallows. All treatments were repeated with and without an initial triple superphosphate application of 250 kg Plha. After 7 (8.5 years), soil organic carbon (SOC) increased significantly under grass and declined under sorghum and bare fallow. Residue transfer treatments gave no significant effect on sorghum biomass or extractable (Olsen) P. Removal of residues caused decline in SOC.P fertilizer increased crop biomass only in five of the first eight seasons and SOC was unaffected. In the 18thto 20th seasons, sorghum was replaced by maize (zea mays) in an N x P factorial design within each of the initial P treatments. Biomass increased only if both N and fresh P were supplied and initial P had no effect. Precapitalization was inefficient because P recovery was low, so a "little and often" regime for fertilizer P appears betterItem Management of Acid Soils in Central Kenya Highlands(2013) Kihanda, F.M.; Muriithi, C.; Mwangi, M.The Ando-humic Nitisols within the highlands of central Kenya are characterized by low soil pH, low exchangeable bases and high percent Aluminium saturation resulting in low maize yields. An experiment was conducted to determine the effect of NP fertilizers (0 or 50 kg N & P205/ha), K (0 or 50 kg K20/ha), agricul turallime (L) at 0 or 1.0 t/ha and farmyard manure (FYM) at 0 or 5.0 t/ ha on maize yield and soil chemical characteristics over a period of eight years. The treatments were arranged in a Randomised Complete Block Design replicated two times. There was no significant increase in maize yield due to K application. Lime increased the maize grain yield by 156 % whereas the application of either FYM or NP fertilizer resulted in similar increases in maize grain yield (90 %). The highest maize grain yield of 4.5 t/ha was obtained by a combination of NP, lime and FYM. The highest (1.4 %) loss in organic C of was observed in plots that had not received any NP fertilizer and FYM. Agricultural lime increased the soil pH from 4.4 to above 5.5 irrespective of the NP or FYM treatments. Aluminium saturation decreased to zero in the plots that had received lime. There was a large increase in soil exchangeable Ca when lime was applied.Item Upper Tana Natural Resources Management Project (Utanrmp) Activities Implemented By KALRO Embu(Kenya Agricultural and Livestock Research Organization, 2018) Wanderi, S.; Muriithi, C.; Kihanda, F.; Kenya Agricultural and Livestock Research OrganizationIncrease breeder, basic, certified seed and clean planting materials of improved varieties and avail quality seeds to the farmers. Target crops are cereals (maize – KH500-39E & Embu synthetic), legumes (beans, cowpeas, green grams, pigeon peas), root & tuber crops (Irish potatoes, cassava and sweet potatoes) and fodder crops. Build the capacity of small-scale farmers/farmer groups and extension staff through training in seed production protocols. Establish sustainable seed production by involving contract seed growers and community based seed producers (CBSP).
