Biomass-Based Fertilizer Formulation Using Chemically Decomposed Agricultural Wastes and Evaluation of Its Efficacy in Growing Maize
Loading...
Date
2020
Authors
Echessa, A.C. Peter
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Utilization of the conventional fertilizers such as NPK, DAP, CAN and Urea by
smallholder farmers in developing countries like Kenya has remained dismal due to high
retail prices as well as environmental and soil related concerns such as P-fixation, leaching
and volatilization. Organic fertilizers generated using traditional composting methods
come in handy despite own challenges of long composting periods, imbalanced nutrients
and environmental impacts of pathogens. The long composting period can be shortened
through chemical decomposition of selected farm wastes that can provide balanced
nutrients. The objective of this study was to utilize chemically decomposed agricultural
wastes to formulate a biomass-based fertilizer and evaluate its efficacy in growing maize.
Selected agricultural waste (maize cobs, maize stalks, sugar cane bagasse, sisal leaf pulp
and cattle horns/hoofs) were analyzed for nutrients N, P, K and Ca to determine their
suitability for formulating a Biomass-Based Fertilizer (BBF). Results indicated that the
agricultural wastes had varied levels of macronutrients sufficient to support use in fertilizer
formulation. The acidic sisal leaf pulp required basic conditions to decompose. The lye
from burned maize cobs was used to digest sisal leaf pulp to give a basic cobs ash sisal
digest (CASD) product while cattle horns and hoofs soaked in peracetic acid gave an acidic
horns and hooves digest (HD) product. HD (acidic) was mixed with CASD (basic), (HD:
CASB) in varying ratios to give different fertilizer formulations namely, BBF0 (0:1), BBF1
(1:1), BBF2 (2: 1), BBF3 (3:1), BBF4 (1:2) and BBF5 (1:0). The formulations had pH
varying from 6.82±0.15 to 8.41±0.27 and would provide macronutrients in the ranges of
1.0-3.9 g (N), 0.002-0.17 g (P), 0.001-6.30 g (K) and 0.08-9.20 g (Ca) per plant
environment. Fertilizer formulation BBF1, with pH above 7.5 and macronutrients 2.31%
N, 0.08% P, 2.5% K and 3.46% Ca, was used in efficacy study carried out in Lugari,
Kakamega county because of the acidic nature (pH<7.0) of the field soils. Plant height and
yield of maize under the BBF1/BBF1 and that under the DAP/CAN schedules were
comparable, but differed significantly from those of maize in the plots without fertilizer
schedule. Side dressing maize whose leaves developed purple coloration (phosphorus
deficiency) with freshly prepared BBF1 cleared P-deficiency symptoms in ≤ 7 days.
Chemical decomposition of agricultural wastes produces digests that blend into a BBF
formulation that is effective in promoting growth and yield of maize crops.
Description
A Thesis Submitted in Partial Fulfillment of the
Requirements for the Award of the Degree of Doctor of
Philosophy in the School of Pure and Applied Sciences of
Kenyatta University
November
Keywords
fertilizers, NPK, DAP, Organic fertilizers, Kenya