Light fraction of soil organic matter under different management systems in Abeokuta, a derived Savanna, Nigeria

Abstract

A study on light fraction organic matter was carried out on the soil from three different management systems namely; Gmelina arborea, Tectona grandis and Leucaena leucocephala plantations in the University of Agriculture, Abeokuta Nigeria. Soil samples were collected in each of the three management site at five auger points within the site at 0 – 10cm and 10 – 15cm depths with the aim of investigating the influence of soil management practices on the light fraction content of soil organic matter. The result showed that (Light fraction) LF nitrogen was highest in
Leuceana stand (0.14g/kg) and lowest in Gmelina stand (0.12g/kg) at 0 – 10cm depth. Similar trend was recorded for LF carbon; Results showed no significant (P<0.05) difference in Total Carbon in the 10 – 15cm depth. High organic carbon in light fraction and microbial population of 0-10cm depth in all the three land management systems probably reflects the distribution of plants and microbial debris within the soil profile as reflected. High LF nitrogen and LF organic matter in Leuacaena stand was probably due to the ability Leuacaena to fix nitrogen to the soil and
which could also be responsible for high microbial population (8.06 x 106). This is further enhanced by the significant positive correlation between organic matter and microbial population. Overall, the study revealed that
light fraction contents provide a sensitive and reasonably precise measure of organic matter indices in the study area