Comparative Effect of Compost Manure and Inorganic Fertilizer on Selected Enzymatic Activities of Cocoa Seedling Rhizosphere

Abstract

Soil enzymes activities have been proposed to evaluate the sustainability
and economic effects of agricultural practices, and even to diagnose the
soil categories. In this study, the effect of soil amendment on the activities
of urease and dehyrogenase in the rhizospheres of cocoa seedlings were
analyzed. Cocoa seedlings were self-grown in nursery located at the
Orchard of the Faculty of Agriculture, University of Benin and
Amelonado variety Tc1-Tc8 pods were used. The seeds were prepared,
pre-germinated and planted in bags containing 5 kg top soil. Organic
fertilizers (compost poultry manure and cow dung) and inorganic
fertilizer was applied to the soil surrounding the seedlings at one month
after planting. The sowing soil and the rhizosphere of the cocoa seedlings
at one month to four month were collected and analyzed. The physical
and chemical analysis of the sowing soil and the organic contents of the
organic fertilizers were investigated and the activities of the enzymes:
dehydrogenase and urease were assayed using standard procedures. It
was observed that the Nitrogen: Phosphorus:Potassium (NPK) content of
the poultry manure (4.11:33.43:6.00) was higher than that of the cow
dung (1.75:0.84:5.52). The enzymatic assay showed soil amended with
poultry manure having the highest dehydrogenase (11.58 – 12.34) and
urease (15.80 -16.90) activities; while that of NPK (10.46 – 10.53) and
(14.32 -14.52) recorded the least enzymatic activity respectively.