Agricultural Soil is a mixture of minerals, organic matter,
gases, liquids, and countless organisms that together support life on
earth. The use of compost or organic manure is currently being advocated
as an option for improving soil fertility.
The method used in carrying out this analysis for cyanide, macronutrient (N,P,K) are titrimetric method, NO3 – UV spectrophotometric method, vanadomolybdo phosphorus acid method, and direct air-acetylene flame method respectively.
From the experimental analyses, the
result obtained for the test of macronutrient (N,P,K) ranges from (-0.01
to 354.956) which shows that there was an increase in macronutrient
before composting, after the composting process, there was a decrease in
macronutrient. For cyanide it ranges from (-0.001 to 0.1) which also
shows that cyanide was not found in the soil before composting, but
after the composting process there was cyanide in the soil. For pH, it
ranges from (3.1 to 6.72), with a mean value of 5.605 which shows that
the soil was moderately acidic.
Kinetics of macronutrient (potassium)
shows that there was an increase in concentration with respect to time,
which has a second order reaction, with rate constant (K) of
Conclusively, from the overall analysis
it could be seen that cassava leaves compost has a bad effect on
macronutrient content of agricultural soil.
1.1 Background ofthe Study
Soil is a major component of the earth's ecosystem. The world's ecosystems are impacted in far-reaching ways by the processes carried out in the soil, from ozone depletion and global warming, to rainforest destruction and water pollution. Apart from the atmosphere, the soil is the next largest carbon reservoir on earth, and it is potentially one of the most reactive to human disturbance and climate change(Bryant, 2006).
The chemistry of soil determines its ability to supply available plant nutrients and
affects its physical properties and the health of its microbial
population. It also determines its corrosivity, stability, and ability
to absorb pollutants and to filter water. It is the surface chemistry of
mineral and organic colloids that
determines soil's chemical properties. "A colloid is a small,
insoluble, nondiffusible particle larger than a molecule but small
enough to remain suspended in a fluid medium without settling. Most
soils contain organic colloidal particles called humus as well as the
inorganic colloidal particles of clay." The very high specific surface area of colloids and their net charges, give soil its ability to hold and release ions.
The use of compost or organic manure is
currently being advocated as an option for improving soil fertility.
Organic manure or fertilizer increase the soil organic carbon pool and
soil pH, improves the soil structure, decreases bulk density, provides
macro- and micronutrients and enhances microbial activity. Most farmers
use crop residues as feed for their livestock or as fuel. Thereby
leaving only low quality plant residues for composting to generate soil
to organic matter that has been decomposed by soil flora and fauna to
the point where it is resistant to further breakdown. Humus usually
constitutes only five percent of the soil or less by volume, but it is
an essential source of nutrients and adds important textural qualities
crucial to soil health and
plant growth. Humus also hold bits of undecomposed organic matter which
feed arthropods and worms which further improve the soil.This results
in poor quality composts (Brancaet al., 2013).
Therefore, the Alliance for a Green Revolution in Africa has adapted
integrated soil fertility management as a base for increasing crop
productivity and restoring soil fertility. This strategy aims to combine
organic and inorganic fertilizers, resulting in a synchronized nutrient
release and uptake by the crop (Killhamet al., 2010).
The aim of this research is to investigate the effects of cassava leaves compost on soil properties.
1.2 Problem Statement
Cassava processing produces large amount
of waste (cassava leaves) and is generally considered to contribute
significantly to environmental pollution (FAO, 2001). In Nigeria (Oleh
community)cassava waste leaves are usually left to rot away in open
(agricultural soil), thereby altering the presence of heavy metals in
the soil, the pH of the soil and the content of macronutrient available
for plant growth.
Cyanide is concentrated in the cassava
leaves and when the cassava leaves is decompose on the soil, it reduces
the power of the macro nutrient on the soil which may lead to poor
fertility of the agricultural soil.
High concentrations of cyanide can
inhibit respiration and affect a plant’s ability to absorb nutrients
from soil, in some cases causing plant death, cyanide diminish new
growth and can affect the germination of seeds. Cyanide in the soil may
therefore prove fatal to plant life.
1.3 Scope of the Study
The scope of the present study is to
investigate the effect of continuous application of cassava leaves
compost on agricultural soil, in a selected locality of Oleh town.
1.4 Relevance of the Study
Soil tests measure the relative nutrient
status of soil and are used as a basis for profitable and
environmentally responsible fertilizer application. The accuracy of a
soil test result is influenced by the laboratory analysis but may be
influence even more by the quality of the soil sample. Sample collection
is extremely important in the accuracy and repeatability of a soil
test. Sample handling following collection is also important. A soil
sample which does not represent the area being sampled will be
misleading and result in over or under-application of fertilizer. It is
therefore very important to collect and handle soil samples properly.
This work will help to direct soil
Samplers in methods for determining a composite soil test, but will also
introduce site-specific methods for revealing within-field nutrient
levels. The challenge has been to provide meaningful information about
field and within field nutrient levels with minimal cost to the
1.5 Aim and Objectives of the Study
The aim of this work is to determine the
macronutrient contents of cassava leaves composted agricultural soil:
Specific objectives include;
- To know the effect of cyanide present in the soil.
- To analyze the soil pH (check if it is acidic or not) and know the range.
- To measure the increase/decrease of the soil macronutrients resulting from the application of cassava leaves compost.
- To know the kinetics behind the study.