Effects of Organic and Inorganic Fertilizers on the Soil Carbon Sequestration Influence of Mavuno and Manure Fertilization on Soil Carbon Fractions

A soil’s ability to resist erosion and maintain high levels of carbon (C) and nitrogen (N), rests in the distribution of soil fractions. Human soil management practices, such as tillage practices, alter the fraction distribution and subsequently the ability to sequester soil C and resist erosion. The objective of this study was to look at the influence of organic farm yard manure (FYM) and inorganic fertilizer (mavuno) on C fractions in soils from two counties in Kenya. The treatments applied were Imazapyr Resistant (IR) Maize (control), manure, and mavuno+ manure. Soils were wet sieved to separate into fractions and subsequently analyze the fractions for C content. Results indicate that there were significant differences in carbon content amongst the fractions with the largest carbon c in the silt and clay fractions There were however no significant differences in the proportions of the large macro-aggregates (LM), small-macro-aggregates (sM), micro-aggregates (m) and silt and clay (s+c) in different sites, treatments and fertility gradients. Elemental combustion was carried out and significant differences in C and N fractions were observed with the highest being 2.05% C and 0.18% N in the silt and clay fraction. A combined application of both manure and mavuno, increased overall N and C in fractions. The treatments, fertility gradients and sites had no effect on the carbon fraction distribution.

Keywords
soils; carbon sequestration; organic carbon fractions; mavuno; farm-yard manure