Philippine Journal of Science
152 (4): 1495-1505, August 2023
ISSN 0031 – 7683
Date Received: 28 Dec 2022
Effects of Bio- and Chemical Fertilizers
on Growth and Soil Microbial Population
of Cacao (Theobroma cacao L.) Seedlings
Kristel S. Victoria and Nelly S. Aggangan*
National Institute of Molecular Biology and Biotechnology,
University of the Philippines Los Baños, Laguna 4031 Philippines
*Corresponding author:
nsaggangan@up.edu.ph; nellysaggangan@gmail.com
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Victoria K, Aggangan N. 2023. Effects of Bio- and Chemical Fertilizers on Growth and Soil
Microbial Population of Cacao (Theobroma cacao L.) Seedlings. Philipp J Sci 152(4): 1495–1505.
https://doi.org/10.56899/152.04.18
ABSTRACT
A comparative study was done to determine the growth, microbial population, and physicochemical properties on UF18 cacao (Theobroma cacao) seedlings when treated with chemical fertilizers and biofertilizers, either applied singly or in combination. The experimental design was randomized completely block design with five seedlings per treatment per block. Treatments used were: control, ½ recommended rate of chemical (RRC) fertilizer, RRC, MYKORICH®, MYKOCAP®, ½ RRC + MYKORICH®, ½ RRC + MYKOCAP®, RRC + MYKORICH®, and RRC + MYKOCAP®. MYKORICH® and MYKOCAP® contain 12 species of arbuscular mycorrhizal fungi isolated from stressed environments. The results showed that plant growth and physico-chemical properties were significantly improved by the application of biofertilizer than by chemical fertilizer. MYKORICH® treatment gave the highest spore count and is highly significant (p < 0.05) as compared to the other treatments with spore count ranging from 41–115.5/ 50 g soil. In terms of nitrogen-fixing bacteria count, ½ RRC treatment gave the highest (16.9 CFU x 10–5 g soil–1) bacterial count. RRC + MYKORICH® inoculation gave the highest values for most of the soil physico-chemical analysis (pH, P, K, and CEC). The positive response of cacao seedlings to mycorrhizal inoculation with or without chemical fertilizer provides a useful criterion in other agricultural lands throughout the country for crop production and sustainability.