Effects of Organic and Organomineral Fertilizers on Soil Physical Properties, Growth and Yield of Tea in Kericho County, Kenya
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Date
2020
Authors
Kiprotich, Hassan
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Tea production in Kenya provides a livelihood to over six million people and its
productivity is influenced by soil fertility. Maximum tea yields are obtained when
correct soil nutrients are available in the soil. Long term use of inorganic fertilizer in
tea as a mono-crop often results in moribund of tea fields. This study was conducted
to evaluate the yields, growth rate and physiological responses of tea clone TRFK
31/8 to three sources of fertilizer sheep manure, enriched sheep manure and
inorganic fertilizer NPK (26.5.5). The organic fertilizer and enriched organic
fertilizer was applied at four rates of 60, 120, 180 and 240 Kg/ha while NPK 26:5:5
was applied at the rate of 180 Kg /ha and the effects of these applications on the soil
physical properties. The trial was done at the Tea Research Institute, Kericho where
trials were laid out in Randomized Complete Block Design (RCBD) and replicated
three times. The parameters measured included: photosynthetic rate, stomatal
conductance, transpiration rate, shoot growth, soil pH, soil hydraulic conductivity,
porosity and soil aggregate stability. Collected data was subjected to analysis of
variance (P≤0.05) using SAS statistical package version 9.1 and treatments means
separated using Fisher’s Least Significant Difference (LSD). The apical shoot
growth was significantly highest at a ratio of 4 organic: 1 DAP at a rate of 120
Kg/ha with a peak of 2.93 cm in the wet season at week 4. The highest soil pH was
recorded under sheep manure (5.94) at a rate of 240kg/ha while the lowest recorded
(3.81) was under the NPK alone at a rate of 180 kg/ha. The hydraulic conductivity
increased linearly under the sheep manure, enriched sheep manure at both ratios of
4:1 and 8:1 as the NPK rate increased while the lowest (0.20 m s-1) was recorded at
the NPK treatment for the wet and dry seasons. The highest yield was recorded in
the enriched sheep manure at a ratio of 8 sheep manure to 1 DAP at 180 Kg/ha with
1019.3 and 917.3 kg/ha for the wet and dry seasons, respectively. The use of
enriched sheep manure and DAP at a ratio of 8:1 is recommended and will ensure
increased yields and reduced soil degradation in tea production.
Description
A Thesis Submitted in Partial Fulfilment of the Requirements for Award of the
Degree of Master of Science in Agronomy in the School of Agriculture and
Enterprise Development, Kenyatta University
Keywords
Organomineral Fertilizers, Organic Fertilizers, Soil Physical Properties, Tea yields, Kericho County, Kenya, Tea production