MST-School of Agriculture and Enterprise Development

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This collections contains bibliographic information and abstracts of Master theses and dissertation in the School of Agriculture And Enterprise Development held in Kenyatta University Library

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Browsing MST-School of Agriculture and Enterprise Development by Author "Danga, B. O."

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    Effect of Combining Cattle Manure and Inorganic P-fertilizer on Soil Properties and Maize Yield in Acidic Soils in Beira Corridor, Mozambique
    (2014-02-19) Muambole, Arlindo; Danga, B. O.; MIGUEL, MAGALHÃES A. MIGUEL
    Mozambique lags behind all other Southern and Eastern African countries in maize production leading to maize imports. Soil nutrient depletion, lack of combination of organic resources with mineral resources coupled with high soil acidity has been identified as the main causes of the declining crop yields. Maize yield in smallholder systems in central Mozambique can be increased by optimum utilization of mineral fertilizers combined with cattle manure and other locally available organic resources. The aim of this study was to evaluate the effect of combining cattle manure and inorganic P-fertilizer on soil properties and maize yield in acidic soils along Beira Corridor, Mozambique. The objectives were to evaluate the effect of combined incorporation of cattle manure and mineral fertilisers on soil properties and maize yield; to determine the optimum rate of manure-inorganic fertiliser interactions for increased fertilizer use efficiency and to assess the profitability of combined application of cattle manure and mineral fertilisers for small scale farmers. The experiment consisted of combination of three levels of inorganic P-fertilizers (TSP) at 0; 25 and 50 kg ha-1 (P2O5) with three levels of cattle manure (0, 5 Mg/ha and 10 Mg/ha). The total treatments tested were nine and arranged in RCBD with four replications. Analysis of variance (ANOVA) was used for data analysis, and treatment means were compared at probability (p<0.05) using Least Significant Difference (LSD). Cattle manure at 10 Mg/ha combined with TSP at rate of 50 kg/ha gave higher maize grain yield of 4.87 Mgha-1 compared to 0.55 Mgha-1 of the control. Combination of mineral fertilizers with manure significantly increased phosphorus use efficiency by 98%; phosphorus agronomic efficiency by 87%; phosphorus recovery efficiency by 0.46 g kg-1 and utilization efficiency by 98%. Inorganic P-fertilizer use was cheapest when TSP as source of P was combined with manure at rate of 5 Mg ha-1 having Value Cost Ratio of 8.12 but P-fertilizer (as TSP) was most expensive when applied without manure, having VCR of 3.40. Advocacy on combination of cattle manure that is locally available with TSP should be increased to improve soil properties, crop yield, fertilizers use efficiency, income and profit to farmers.
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    Effects of different organic residues on carbon sequestration, nutrient availability in soil and maize yields at Katumani, Machakos county Kenya
    (Kenyatta University, 2015-01) Mbaluka, Titus Luta; Danga, B. O.; Mugwe, J. N.
    Reduced farm productivity in smallholder farms is the principal cause of food insecurity in semi-arid parts of Kenya. This is mainly attributed to soil fertility depletion, land degradation, low soil moisture and climate change. Climate change due to increased carbon dioxideemission into the atmosphere has impacted negatively on the food productivity in Africa.The objectives of this study were: 1) to determine the effect of different organic residues on soil carbon accumulation in soil. 2) to determine the effect of organic residues on the availability of nutrients into the soil, and 3) to determine the effect of different organic residues on maize growth and yields. Field studies were carried out in two seasons (2011/2012 short rains and 2012 long rains) at Kenya Agricultural Research Institute (KARI) – Katumani Dry land Research Centre in Machakos County. Maize residues and compost manure were used, under different application methods and a control where no organic residue was applied. This constituted seven treatment combinations as follows; 1) Control, no organic residue application; 2) 10 ton/ha compost, surface application; 3) 10 ton/ha compost, incorporated application; 4) 5 ton/ha maize stover, surface application; 5) 5 ton/ha maize stover, incorporated application; 6) 5 ton/ha maize stover, 10 ton/ha compost, surface application; 7) 5ton/ha Maize stover, 10 ton/ha compost, incorporated application). The seven treatments were laid out in a randomized complete block (RCBD) design with 3 replications. Soil samples were collected from 0-20cm and 20-40cm depths before planting, at six weeks after planting and at harvest. The soil samples were analyzed for total C, total N, soil pH, available P, Mg, Ca, Na, K and CEC. Maize grain yield and total dry matter was measured. Statistical analysis of data was done using analysis of variance (ANOVA) and means separated using LSD at p=0.05. Results of this study showed that total soil organic carbon increased with application of organic residues. Treatments that had 5ton/ha maize stover and 10 ton/ha compost, incorporated recorded the highest soil carbon accumulation of 0.36 Mg C/ha and 0.39 Mg C/ha at the end of season one and two, respectively while the control decreased by 0.02 Mg C/ha in season 1 and 0.03 Mg C/ha in season two. Nutrients concentrations in the soil were found to increase with application of organic residues where by incorporated 5 ton/ha maize stover and 10 ton/ha compost treatment recorded the highest concentrations of most nutrients in the soil. Maize yields increased with the application of organic residues. Treatments that had 5 ton/ha maize stover and 10 ton/ha compost under incorporated application gave the highest maize grains which was 145% more, compared to the control in season one and 248% in season two. In conclusion combining 5 ton/ha maize stover and 10 ton/ha compost under incorporated application could be a promising soil fertility management strategy for improved carbon storage in soils and for increased maize productivity.
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    Effects of Lime, inorganic P and inoculation on Soil Chemical properties and Grain Yields of Maize and Soybean in Western Kenya
    (2013-10-17) Onyango, Maurine Akinyi; Danga, B. O.; Odendo, Martins
    Low crop responses to fertilizer application among small holder farms are common phenomena in degraded acidic soils of western Kenya. Continuous growing of maize without commensurate soil nutrient replenishment coupled with application of soil acidifying fertilizers, especially Di-ammonium Phosphate (DAP) and Sulphate of ammonia (SA) have aggravated the soil acidity problem. An on-farm trial was sited in Shianda sub-location, East Wanga division in Mumias district, Western province, Kenya during the 2011 long rain (LR) and short rain (SR) seasons to determine the effect of lime, inorganic P, inoculation on soil chemical properties and yields of soybean (Glycine max L.) and maize (Zea mays L.). The treatments included, 2 lime rates (0, 2.5 t/ha), 2 inorganic Prates (0, 30 kg P/ha) with or without inoculation (Rhizobium japonicum) of soybean. The eight treatments were arranged as factorial in RCBD with four replicates. All data were analyzed with the ANOV A procedure of the GENST AT statistical software and treatment means separated using least significance difference at (P < 0.05). Regression analysis was performed to examine relationships between plant and soil parameters. Benefit-cost analysis was performed on maize and soybean grain yields to determine the treatments with the most profitable returns. A combination of Lime + P + inoculation recorded the highest maize (4490 kg/ha, 3470 kg/ha) and soybean (970kglha, 830kglha) grain yields during the first and second seasons, respectively. Sole P treatment gave a higher average nodule number per plant and plant biomass (g), respectively (8 and 21.8) than sole inoculation (4 and 19.2) and sole lime treatments (2 and 16.8) during the first season. Lime application at Z.5 t/ha increased soil pH from 4.9 to 5.58. Increase in soil available P was in the order' of lime> P > inoculation (9.35 > 6.50 > 5.10) mg/kg. Sole lime treatment proved 'to be a more profitable investment for the farmers as it gave. a net benefit of Ksh 89,015.20 with a benefit-cost ratio (BCR) of 2.2. Therefore, integration of lime, inorganic P and inoculation needs to be disseminated among small-scale farmers in western Kenya for improved maize and legume production.
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    Lime and Manure Application to Acid Soils and their Effects on Bio-Chemical Soil Properties and Maize Performance at Kavutiri - Embu County
    (2014-02-22) Gitari, Harun I.; Danga, B. O.; Mochoge, B.O.
    Soil acidity is widespread globally, accounting for about 40% of total arable soils. In Kenya, acid soils cover about 13% of total land area and are distributed widely in the croplands of central and western Kenya regions, covering over one million hectares. The main limitation of crop productivity in Kavutiri, Embu, is soil acidity and more specifically aluminium toxicity. The objective of this study was to determine the effects of agricultural lime in combination with farmyard manure (FYM) on soil properties (exchangeable acidity, pH, and microbial biomass) and maize growth. The treatments include: goat manure at 3 levels (0, 5 and 10 Mg ha-1) and agricultural lime (CaCO3) at 6 rates (0, 2.5, 5, 7.5, 10, and 12.5 Mg ha-1). The study was carried out in two phases. Phase 1 was carried out at the greenhouse with pots arranged in a complete randomised design (CRD) and replicated thrice while phase 2 was carried out on a farmer’s field at Kavutiri where the soil samples for phase 1 were taken. Only the best three performing treatments in phase 1 were selected and verified during phase 2 in a complete randomised block design (CRBD) with three replicates. In each phase, maize was the test crop and was grown for a period of 8 weeks. The biophysical data generated from the study was analysed using Analysis of Variance (ANOVA) in Genstat statistical package. Treatment means were compared at probability p< 0.05 using Fischer’s least significant difference (L.S.D). Results of this study indicate that soil acidity decreased with increase in manure and lime levels. The treatment M10L12.5 –with 10 Mg ha-1 of manure and 12.5 Mg ha-1 of lime - recorded the highest pH of 6.3 and 5.9 for greenhouse and field trials, respectively. Maize growth parameters (root length, height and biomass dry weight) were found to increase significantly as levels of manure and lime increased. Treatment M10L12.5 from greenhouse trial recorded the highest values for root length (41.3 cm), height (150.3cm) and dry biomass weight of 755.4 Kg ha-1. Microbial biomass was found to be higher in the field than in greenhouse trials with the highest value of 28.8 × 105 and 26.7 × 103 Colony forming units (CFU) for bacteria and fungi, respectively. This marked significant increases (P < 0.05) of 772.7 and 86.6% for bacteria and fungi, respectively above the control. From the study, it was concluded that combining 10 Mg ha-1 of FYM and 12.5 Mg ha-1 of agricultural lime could be a promising alternative amendment for acid soil management strategy for increased maize production at Kavutiri and other related soils in Kenya.