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populations have been reported by the application of organic manures (Senjobi et al., 2013). However a single
recipe would not be generally applicable in different conditions. For instance, application of PM and SBE, which
is a form of ash, had significantly improved the physical and chemical properties of soils as evidenced by this
experiment. Fernandez et al. (2013) and Christo et al. (2011) reported an increase in the pH and fertility of soil
with combine application of ash and organic manure.
Increased in vegetative growth of maize at 2WAP and 8WAP in this present study could be attributed to the
combined application of SBE and PM at their highest rates, which supplied the nutrients required and provided
suitable ecology for microbial build-up. This agrees with the work of Christo et al. (2011); Soretire and Olayinka
(2013); Ogunrewo and Olayinka (2013); and Fernandez et al. (2013).
There were significant (P<0.05) difference in yield and leaf nitrogen content of maize at harvest. These depended
on the level of SBE and PM applied. Plots which had been fertilized with higher rate of SBE and PM exhibited
higher yield than those that received lower rates, this could be attributed to large quantities of available
phosphorous and potassium in the PM. Also, SBE contains large quantities of silicon which mobilizes the
availability of cations to the plant roots. Rao (1991) reported that soil could be enriched by application of higher
quantities of organic materials which tends to decompose and release large amounts of nutrients, mainly nitrogen,
phosphorous and potassium into the soil. Another study by Xu et al. (2005) showed that higher levels of organic
manure produced better vegetative growth and resulted in a final higher total yield than those grown on lower
amount of manure. In this study productivity of maize increased with increase in the quantities of SBE and PM
combined. The trend of increase in maize yield was linear in the direction of additional input of SBE and PDM
combination. However, there was no significant difference in the vegetative growth, yield and leaf nitrogen of
maize between 7.5 and 10 t/ha
-1
SBE in combination with 10 t/ha
-1
PM (P<0.05). This could be as a result of
increased soil pH which does not always bring the expected result in the immobilization of some trace metal like
zinc that is needed by maize for good growth and yield. Pendias and Henryk (1985) pointed out that the metals
that are most likely to occur in soil as organic chelates in larger particulates may become soluble quite easily after
heavy liming, as has been reported mainly for Cu, Zn and Cr. This emphasis is similar to the observation of this
experiment.
Separate application of PM and SBE increased growth and leaf nitrogen of maize in inland valley swamp. It was
the combined use of the materials (PM and SBE) that most enhanced growth and yield parameters. This can be
adduced to the release of nutrients to synchronize with the growth of the maize plant. The PM and SBE releases
nutrients and reduced the acidic nature of the inland valley swamp soil of the study area.
There is synergistic relationship between PM and SBE since the silicon in SBE will stimulate the build-up of
higher pH value which influences microbial activity and mineralization of nutrients from the PM. This reaction is
expected to improve uptake of nutrient by maize plant. It can be seen that application of 10 tons PDM and 7.5-10
tons of SBE is suitable for ameliorating acidic nature of Inland Valley Swamp and increasing plant productivity
for sustainability.
5 Materials and Methods
5.1 Study location
The study was conducted at the Teaching and Research Farm, Rufus Giwa Polytechnic, Owo, a humid rainforest
zone, south-western Nigeria (Lat. 7
o
14
ʹ
N and Long. 5
o
08
ʹ
E) and 35 meters above sea level. The mean annual
rainfall is between 1300-1600 mm, bimodal in distribution, usually March to July and September to October, with
characteristics August break. There are two distinct season- the wet season, which extends from March to October,
and the dry season which is usually from November to February. The average temperature is 30
°
C. Relative
humidity ranges between 85% during the rainy season and less than 60% during the dry season. The soil at the site
of study is a tropical rainforest sandy loam Alfisol, classified as Clayey Skeletal Oxic-Paleustalf (USDA Soil
Taxonomy, Soil Survey Staff, 1999).
