Assessment of changes in nutrient status of tropical lowland soil amended with leaf biomass of some agroforestry tree species Assessment of changes in nutrient status of tropical lowland soil amended with leaf biomass of some agroforestry tree species

Abstract

This research was aimed at assessing the nutrient status of tropical lowland soil; through the application of leaf biomass of some selected tree species evaluate the effect of the leaf biomass on soil nutrient status and also determine the changes in nutrient status in the past decades. Leaves from Anogeissus leiocarpus, Enterolobium cyclocarpum, Gliricidia sepium, Leuceana lucocephala and Treculia Africana at the rate of 5 tons per hectare (5t haˉ¹) were assessed. Soil samples were collected at the forest nursery of federation university of agriculture Abeokuta at 2, 4, 6, 8 and10 weeks after application of, organic carbon, total N, P, K, Ca, Mg and Na were analyzed in a split plot experimental design with the main plots being the time of soil sampling and the sub-plots mulch type means were separated. Leuceana lucocephala was observed to have the highest nutrient release capacity given its value for the following nutrients; total nitrogen 0.019, calcium 41.07 and sodium 139.0 Control plot has the highest organic carbon 3.12 content followed by Enterolobium cyclocarpum, 3.05 as well as highest pH value 6.45 The highest phosphorous content was recorded in Treculia africana 466.6 plot followed by Leuceana lucocephala 3.05. Enterolobium cyclocarpum however recorded the highest potassium 90.0 and magnesium 152.5 content. The rapid decomposition of Leuceana lucocephala and its nitrogen fixing ability is an indication that it is a good replacement to fixing soil nutrient in lowland soil.