Sibusisiwe, Caroline Kamanga (2013) Effect of Organic and Inorganic Fertilizers on Soil Properties, Striga Density and Maize Yield in Vihiga and Siaya Counties, Kenya. Masters thesis, University of Nairobi.
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PDF (Effect of Organic and Inorganic Fertilizers on Soil Properties, Striga Density and Maize Yield in Vihiga and Siaya Counties, Kenya)
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Abstract
Continual soil fertility depletion and the increased infestation of weeds such as striga in smallholder farming systems are two of the main processes amplifying reduction in food production across Sub-Saharan Africa (SSA). These conditions are aggregated even further by the existence of soil fertility gradients in small-holder farmer fields resulting in varying crop yields in a single farm. Against this backdrop, this study aimed to assess the effects of fertilizer application on soil properties, striga density, and maize yield in small-holder farmer fields with existing soil fertility gradients. The study was conducted in Emusutswi in Vihiga County, and Nyabeda and Nyalgunga in Siaya County. Twelve farmers; four from each site were selected using Y frame sampling and their fields demarcated into low and high fertility status based on a previous study conducted by Tittonel et al 2005. The experiment was set in a completely randomized block design in a split plot arrangement. The fertility gradients were the main plots and the treatments; IR Maize (control), IR Maize+Manure and IR maize +Mavuno+ Manure were the sub-plots. The farmer fields were the replicates. The means of the four farmer fields explained the response of test crop (IR Maize) to applied treatments. The study was conducted during the short rains season. Soil was collected from all the treatments for the analysis of chemical properties- pH, cation exchange capacity (CEC), mineral nitrogen, total N, organic carbon, phosphorus, exchangeable bases (K, Ca and Mg), and biological properties - soil respiration and physical properties – soil fractionation. Striga weed was sampled at week 6, 8, 10 and 12 for striga emergence. Maize yield was determined at crop maturity by sampling from an area of 7.08m2. Results indicated that there were significant differences in P levels across treatment means, (P<0.01) and the mavuno+ manure treatment had the highest mean P levels (11.78%) showing superiority over the control and the manure only treatment. Organic Carbon showed significant differences across treatments and sites (P<0.01). Total N and pH showed significant differences across sites. Mineral N showed significant differences across treatments. Exchangeable bases potassium (K) and calcium (Ca) showed significant differences across treatments whilst Mg showed significant differences across sites. There were significant differences observed in CEC across treatments. There were however no significant differences in the measured soil chemical properties across fertility gradients. Soil respiration showed significant differences across fertility gradients but not across treatments and sites after 7 and 14 days of incubation. Elemental combustion showed significant differences in %C and %N in the fractions with the highest % C (2.052) and % N (0.1816) found in the silt and clay fraction across treatments. Significant differences were further observed in the carbon fractions distributions across treatments and fertility gradients (P<0.01). Significant differences in striga density across treatments (P<0.01) were observed with the control (54,389 plants/ha) having the highest. There were no significant differences in striga density across sites and fertility gradients. Maize yields showed significant differences across sites and treatment means with the highest yield observed in Nyalgunga (mean =4330kg/ha) but no significant differences were observed across fertility gradients. Lack of significant differences in the measured parameters across fertility gradients may necessitate further investigation on the farmer perceived fertility status of their farms. Combined application of FYM and mavuno and the use of IR maize could enhance soil properties, reduce striga occurrence and increase maize yields.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | S Agriculture > S Agriculture (General) |
| Divisions: | Africana |
| Depositing User: | Mr. Senay Abate |
| Date Deposited: | 02 Aug 2016 06:51 |
| Last Modified: | 20 Jul 2017 09:52 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/1286 |
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