Browsing by Author "Kihanda, F.M."
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
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.The possibility of improving soil fertility with a “recapitalization" dose of phosphorus (P) fertilizer in conjunction with crop residues was assessed in a severely P-deficient soil. The experiment comprised three treatments cropped to sorghum (sorghum bicolor): (i) 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 17 (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 18th to 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. P recapitalization was inefficient because P recovery was low, so a "little and often" regime for fertilizer P appears better.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 Kenya Agricultural Research Institute - Regional Research Center-Embu Annual Report 1996(Kenya Agricultural Research Institute, 1996) Kenya Agricultural Research Institute; Gethi, M.; Kihanda, F.M.; Micheni, A.N.; Kenya Agricultural Research InstituteRegional Research Centre Embu, is one of the centers of Kenya Agricultural Research Institute, with a mandate to carry out Adaptive and Applied Research aimed at developing appropriate technologies necessary to improve agricultural production under diverse geo-physical and socio-cultural backgrounds. At RRC-Embu, the activities are conducted under the Regional Research Programme (RRP) that focuses on integration of farm enterprises/resources and mutual collaboration with farmers, agricultural extension agents and other actors in Agricultural development. The Centre has a research mandate for Embu, Mbeere, Meru Central (formerly Meru), Meru North (formerly Nyambene), Tharaka (split from Tharaka-Nithi), Meru South (split from Tharaka-Nithi), Murang'a (recently split into Maragua and Murang'a), Kirinyaga, and Nyeri districts. The mandate districts have a combined area of 18,326 km² of which 59% is agricultural land. The mandate area has a wide range of agro-ecological conditions ranging from the Pyrethrum-wheat (UH₂) to Livestock-millet land use systems (Ls). This document summarizes the annual (1996) results of the various on-farm and on-station research and demonstrations conducted within the centre's mandate areas. It is through the mutual participation of farmers, research scientists, agricultural extension staff and other collaborating stakeholders (individuals NGOs and churches) that the Centre managed to achieve a lot in terms of meeting its challenges. In this context I wish to register my most sincere gratitude to all those who contributed in improving the effectiveness and efficiency in identification of the constraints limiting agricultural production, implementation of research/extension activities and dissemination of the appropriate proved research technologies to farmers.Item 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.
