ABSTRACT
An experiment was
conducted to investigate the effect of complementary use of rice husk ash with
different organic manure sources on soil physical properties, soil organic
carbon stock, growth and yield of maize (Zea
mays) at the research and teaching farm of Federal College of Agriculture,
Ishiagu, during 2017 cropping season. The experiment involves nine (9)
treatments including the control which were as follows: control at 0ton,
poultry manure (PD) 10t/ha, swine manure (SW) at 10t/ha, cow dung (CD) at
10t/ha, rice husk dust (RHD) at 10t/ha, poultry dropping+ rice husk ash (PD
+RHA) at 5 t/ha +5t/ha each, swine manure + rice husk ash (SM +RHA) at 5t/ha
+5t/ha each, cow dung + rice husk ash(CD +RHA) at 5t/ha+5t/ha each, rice husk
dust + rice husk ash (RHD+RHA) at 5t/ha+5t/ha each. The treatments were laid in
a randomized complete block design (RCBD) and replicated three times. Data on
plant height, number of leaves, germination count, stem girth were collected at
2, 4, 6, and 8 weeks after planting (WAP), while the weight of fresh cobs with
husk, weight of fresh of cobs without husk, weight of dried cobs, weight of
shelled grain were determined after harvest and all the data were analyzed using
analysis of variance (ANOVA). Results
showed that poultry dropping when complemented with rice husk ash (PD+RHA) gave
the highest significant (p<0.05) increase on the maize growth parameters. It
was also obtained that the yield components though not significant (p<0.05)
but were increased higher in plots treated with PD+RHA compared to other
treated plots and the control. The shelled grain yield ranged from 0.667 to 0.046.
The results indicated that the macro-aggregates >2.00 mm were significantly
increased higher in the control plots while PD treated plots gave the least
value of 2.03 mm. The micro-aggregates <0.25 mm were significantly
(p<0.05) improved higher in plots amended with poultry dropping. The soil
bulk density was significantly (p<0.05) decreased generally by the
application of soil amendments. Soil pH, organic carbon and total nitrogen were
significantly improved by soil amendments within the period of study. It was
also recorded that the saturated hydraulic conductivity, water retention, water
stable aggregate, and mean weight diameter were significantly (p<0.05)
improved by the manure application.
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background of the Study
Maize (Zea mays L.) is a tall monoecious annual grass
with overlapping sheaths and broad conspicuously distichously blades. The
plants have staminate spike-lets in long spike-like racemes that form large
spreading terminal panicles (tassels) and pistillate inflorescences in the leaf
axils in which the spikelet’s occur in 8 to 16 rows, approximately 30 cm long,
on a thickened, almost woody axis (cob).
The
whole structure (ear) is enclosed in numerous large foliaceous bracts and a
mass of long styles (silks) protrude from the tip as a mass of silky threads
(Hitchcock and Chase, 1999). Pollen is produced entirely in the stimulate
inflorescence and ear, entirely in the pistillate inflorescence. Maize is wind
pollinated and both self and cross pollination is usually possible.
Maize
is cultivated worldwide and represents a staple food for a significant
proportion of the world's population. No significant native toxins are reported
to be associated with the genus Zea
(International Food Biotechnology Council, 1990).Maize is a staple food crop
only in many parts of the tropics and important food for livestock. The grain
is used industrially for starch and oil extraction (Nwite et al., 2011).
Inspite
of the contributions of the crop to the country’s economic development, the
production is still far below the demand of the growing population. In
recognition of the current global food crises, Nigeria currently pursues policy
of expanding the land area under cultivation as well as intensifying crop
production by continuous cropping system, of which maize is included (Nwite et al, 2012).
Poor soil fertility and land degradation are
major limitations to this policy of increased food production and food security
in sub-Saharan Africa, placing many smallholder farmers in a vulnerable
position (Okonkwo et al., 2011). Smallholder farms size in Nigeria are usually
cultivated continuously without adequate replenishment of soil nutrients
(Mureithi et al., 2004, Okalebo et al., 2006).When a soil is cultivated
continuously its productivity gradually decreases due to depletion of organic
matter which is believed to be a reservoir of plant nutrients (Eneje and
Uzoukwu, 2012; Ebaid and EL-Refael, 2007). Cropping may lead to erosion and
leaching of soil nutrients which in turn, adversely affect the physical
properties of the soil and are strong limitations to crop production (Igwe et al., 1995).
The
above problems have necessitated wide range of technological options for
improving soil conservation and land management that are economically viable,
ecologically sound, and socially acceptable. These include inorganic
fertilizers, crop residue management, green manure, composting, farmyard
manure, agro forestry technologies, alley farming, planted fallow, cover crops,
and cereal-legumes intercropping or rotation (Buckles et al., 1998).
Over
the years, use of chemical (inorganic) fertilizer in crop production has not
been sustainable due to its high cost and scarcity, soil acidity, increased
soil bulk density, low water infiltration rate and nutrient imbalance (Ojeniyi,
1995; Nottidge et al., 2005). Thus,
the needs to investigate alternative sources of nutrients that will be less
damaging to the soil environment become imperative. Hence, the recent interest
in the use of agricultural wastes (organic manures) by the dominant resource
poor farmers (Ayeni et al., 2008, Ayeni
and Adetunji 2010). Organic manures such as crop residues and animal excreta
are used directly or composted. However due to high quantity needed, adequate
quantity of an organic waste may not be obtained, hence the farmers often apply
different wastes combined. Since the wastes are of different quantity and
nutrient composition, their combined use is expected to have positive cumulative
and complementary effects in nutrient supply and improvement of crop yield
(Ayeni et al., 2008). Soils in South
eastern Nigeria are generally characterized by low pH and exchange capacity,
poor buffering capacity and rapid loss of fertility on intensive cultivation
(Nwite et al., 2008). Ashes generally
have good acid-neutralizing capacity and ability to supply the soil with basic
elements (Nwite et al., 2011), hence
the reason behind the complementary use of ash material with other organic
manure sources. It has been shown that ash could be used to counteract natural
and anthropogenic acidification of soil and loss of nutrients (Erriksson, 1998;
Serafinelion, 2002).
Maintaining
or increasing soil organic matter (SOM) is critical to achieving optimum soil
function. In many parts of the world, organic wastes represent an inexpensive
and plentiful resource for the treatment of soil quality. However,
investigation of the options for the application of organic wastes and their
efficacy in improving soil condition are needed to assess their potential to
partially or fully replace inorganic fertilizers. Soil organic carbon (SOC) is
the most frequently reported soil attribute from long-term agricultural studies
and is commonly selected as the key indicator of soil quality and agronomic
sustainability because of its impact on other physical, chemical and biological
elements of soil quality (Reeves, 1997). Long-term fertility experiments (LTFE)
play an important role in understanding the complex interaction involving plants,
soils, climate and management practices and are the primary source of
information to determine the effects of cropping systems, soil management,
fertilizer use, and residue utilization on the quantitative and mechanistic
changes on soil quality as well as on SOC pools (Leigh and Johnston, 1994;
Rasmussen et al., 1998).
Soil
organic carbon (SOC) sequestration contributes to the mitigation of greenhouse
gas emissions and to the improvement of soil fertility (Lal R 2004). Net SOC
sequestration is the balance of organic carbon inputs into the soil (via crop
residues, organic amendments in compost, animal manure, etc.) and organic C
decomposition by soil microbes. SOC sequestration efficiency is commonly
expressed by the relationship between annual carbon(C) input and SOC
accumulation rate, which is an indicator of soil C sequestration ability (McLauchlan
2006). Therefore, information about the carbon sequestration efficiency is
useful for seeking high efficiency management strategies of enhancing the SOC
stock and soil fertility. Ash application may help in coping with the low
nutrient levels in this soil. Witt et al.(2005)
showed that nutrient management should be offered great attention in order to
obtain appreciable yield.
Rice
husk is one of the most widely available agricultural wastes in many rice
producing countries around the world. It is of little commercial value and
because of its high valuable for its roles in increasing soil fertility and
improving soil characteristics by its addition of organic matter to the soil
(Njoku et al., 2011). Rice husk
removal during rice refining, creates disposal problem due to less commercial
interest. Also, handling and transportation of rice husk is problematic due to
its low density (Kumar et al., 2012).
Much of the husk produced from processing of rice is either burnt or dumped as
wastes creating great environmental threat to surrounding area where it is
dumped. Therefore, agricultural use of rice husk as organic manure is an
alternative solution to disposal problem (Giddel and Jivan, 2007).
Organic
wastes are those materials such as agricultural wastes, plant debris, animal
dung or their by-products used as soil amendments. These kinds of wastes are
becoming increasingly important in addressing soil low fertility due to
scarcity and high cost of inorganic fertilizers. The local poor resource
farmers had long resorted to use of these materials since they are cheap,
easily available and environmental friendly. Besides, organic wastes have
physical and chemical properties which facilitate aggregation of mineral
particles such as clays which in turn influence soil water regime (Mbagwu,
1990). They are also fundamental source of energy for the soil biota and in
that way influence many biologically medicated processes in the soil
(Stephenson, 1994).
Furthermore,
several studies have been carried out and they indicate positive effect of
organic wastes on soil. They contain nutrients needed for crop growth and
development. Organic matter from such waste improves soil tilt, increase
1.2 Statement
of the Problem
Organic
matter depletion in tropical soil has been discovered to be rapid. The constant
loss of organic matter in the tropical zone has been attributed to high
rainfall, high rate of mineralization (because of high microbial activates bush
burning and high carbon losses accompanying tillage operation. The rapid
depletion of plant nutrients, low organic matters content and poor physical
condition to the soil constitute strong limitations to crop production in the
area regarded as major food belt of the eastern region.
However,
attempts to restore the lost nutrients with the use of organic fertilizers by
rural farmers due the above factors in some soils of the area have led to
population and acidification of the soils.
Organic
matters have being found to improve the physical prosperities of the soil to
maintain better tilt and increase water holding capacity (Ogwuwale et al, 2002). Current the combination of
different organic matter constituent has been found to improve the productivity
of tropical soil more than ordinary use of farm manure.
Furthermore,
several studies have been carried out and they indicate positive effect of
organic wastes on soil. They contain nutrients needed for crop growth and
development. Organic matter from such waste improves soil tilt, increase.
1.3 Objective
of the Study
General Objective
The
main objective of the study is to determine the complementary use of rice husk
ash with different organic manure sources on soil physical properties, soil organic
carbon stock, growth and yield of maize.
Specific objective of the study
will includes
v To
determine the effect of different manure sources on the physical properties of
the soil.
v To
evaluate the effects of different organic manure sources on the growth and
yield of maize.
v To
ascertain the effect of different organic manure sources on the soil organic
carbon stock.
1.4 Justification
of the Study
Soil
carbon level usually increases with organic manure application since organic
manure contains not only nutrients that are essential for plant growth but also
contain carbon. Improving the soil carbon stock through organic amendment is a
good strategy to mitigate climate change as well as giving solution to soil
degradation problem by decreasing the carbon concentration in atmosphere. The
study aimed at proffering solution to options in mitigating climate change and improvement
of degraded soils in south eastern Nigeria through the use of organic
amendments particularly organic manure source.
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