Effect of production and land management systems on soil properties in Murang’a and Kirinyaga counties, Kenya
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Date
2023-11
Authors
Kibet, Jemutai
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta university
Abstract
World population is expected to continue increasing while the arable fields are becoming a threatened resource and unproductive jeopardizing food security in many regions globally. To meet the high food demand agricultural practices have been intensified e.g., by the application of industrial inputs such as fertilizers and agro-pesticides. However, due to the negative impacts of conventional agriculture on environment and human health, organic agriculture is being promoted as an alternative production system. Decreasing soil fertility in Kenya threatening food security is becoming of concern. Thus, this study aimed to investigate soil fertility under organic and conventional management in Kenya’s central highlands. The specific objectives of the study were: 1. to assess the effect of production and land management systems on soil physical properties in Kigumo and Kirinyaga East, 2. to determine the effect of production and land management systems on soil chemical properties in Kigumo and Kirinyaga East and 3, to determine the influence of production and land management systems on soil biological properties in in Kigumo and Kirinyaga East. This study employed a cross-sectional survey approach where the study population on each site was 300 farmers, (117 organic, 183 conventional in Kigumo, and in Kirinyaga east 97 organic and 203 conventional). Due to budget constraints ten farmers from each production system were randomly selected, arable and agroforestry systems were identified in Murang'a and agroforestry systems with macadamia and sole macadamia plantations in Kirinyaga. A total of 72 composite samples taken at a depth of 0-20 cm in Murang'a and 28 in Kirinyaga were collected. They were analyzed using standard procedures at the National Agricultural Research Laboratories, Kabete. The output showed that agroforestry and organic farming systems documented significantly higher soil pH and total nitrogen levels than arable and conventional in Murang’a. Conventional and organic farming systems logged significantly greater levels of soil organic carbon in Murang’a and Kirinyaga respectively. Organic farming system in Murang’a recorded significantly elevated levels of exchangeable basic cations, copper, sodium, and moisture retention and content and rhizobium population. Arable land management recorded significantly higher levels of iron and bulk density in Murang’a. Agroforestry documented significantly greater levels of rhizobium, moisture content, zinc, magnesium and exchangeable magnesium cation. In Kirinyaga, conventional farming system listed greater levels of calcium, manganese and exchangeable magnesium ions. Available phosphorous, iron, copper, bacteria and fungi were significantly higher in organic production systems. The results demonstrate the importance of applying organic soil inputs and retaining crop biomass after harvest to buildup soil organic materials, which acts as a temporary pool of nutrients in the providing living space for soil microbes and enhancing soil health and productivity which in the longrun advances profitability.
Description
A research thesis submitted in partial fulfillment of the requirements for the degree of master of Environmental Science in the School of agriculture and Environmental Sciences of Kenyatta University, November 2023
Keywords
land management systems, soil properties, Murang’a, Kirinyaga counties, Kenya