(CEC), which is important as it translates to more nutrients held in the soils and
reduced acidity (Sinha et al. 2011). Reduced soil acidity can also be influenced by
the neutralizing capacity of most organic fertilizers which can contain about 5%
calcium carbonate in dry matter. The neutralizing capacity of vermicompost has
been reported in a study by Lukashe et al. (2019) in acidic mine-waste-contaminated
soils amended with vermicompost enriched with fly ash. In this study, the original
pH values in the amended soils ranged between acidic 3.7 and 5.3 and were
increased to values close to neutrality ranging between 6.8 and 7.6, following
application of the vermicomposts.
Neutral soil pH values promote nutrient availability, and vermicomposts are
known to provide balanced nutritional release patterns in terms of available N,
soluble K, exchangeable Ca, Mg and P, which are subsequently used by plants
(Singh et al. 2013). In another study, Zhao et al. (2017) applied vermicomposts at
3000 kg/ha to soil reporting an increase in total phosphorus, available phosphorus,
soil organic matter, extractable nitrogen, microbial N and reduced NH 4
+
–N. The
improved fertility of the soil as measured by the mentioned increased parameters was
positively correlated with improved cucumber yields (Zhao et al. 2017). A decrease
in pH with addition of vermicompost in soils has also been reported by Manivannan
et al. (2009), and this was attributed to acidifying effects of organic acids and/or the
increased permeability and leaching of salts. Even so, it is noteworthy that even
though there was a decrease in pH, the change was very slight from 7.15 to 7.08 and
7.14 to 6.97 in clay loam and sandy loam soil, respectively, still maintaining the soil
pH values at neutrality.
18.6.2 Soil Physical Properties
Vermicompost application in soils mainly modifies physical properties such as the
water holding capacity, structure, porosity, aeration, infiltration and resistance to
erosion. Aeration, water retention and improved soil structure are naturally
influenced by soil aggregate stability. Aggregate stability is influenced by polysaccharides from organic matter, which can act as cementing agents between soil
particles in the soil (Mupambwa and Wakindiki 2012). Vermicompost products have
been reported to be also enriched with polysaccharides, which could have an
influence in aggregate stability when applied in the soil (Lim et al. 2014).
Parthasarathi et al. (2008) observed increased porosity in clay-loam and sandyloam soils amended with vermicompost, and the increased porosity was also attributed to the presence of polysaccharides in vermicompost. The increased porosity in
the study subsequently resulted in improved water holding capacity in soils with
vermicompost at 100% relative to soils without vermicompost.
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H. A. Mupambwa et al.
reduced acidity (Sinha et al. 2011). Reduced soil acidity can also be influenced by
the neutralizing capacity of most organic fertilizers which can contain about 5%
calcium carbonate in dry matter. The neutralizing capacity of vermicompost has
been reported in a study by Lukashe et al. (2019) in acidic mine-waste-contaminated
soils amended with vermicompost enriched with fly ash. In this study, the original
pH values in the amended soils ranged between acidic 3.7 and 5.3 and were
increased to values close to neutrality ranging between 6.8 and 7.6, following
application of the vermicomposts.
Neutral soil pH values promote nutrient availability, and vermicomposts are
known to provide balanced nutritional release patterns in terms of available N,
soluble K, exchangeable Ca, Mg and P, which are subsequently used by plants
(Singh et al. 2013). In another study, Zhao et al. (2017) applied vermicomposts at
3000 kg/ha to soil reporting an increase in total phosphorus, available phosphorus,
soil organic matter, extractable nitrogen, microbial N and reduced NH 4
+
–N. The
improved fertility of the soil as measured by the mentioned increased parameters was
positively correlated with improved cucumber yields (Zhao et al. 2017). A decrease
in pH with addition of vermicompost in soils has also been reported by Manivannan
et al. (2009), and this was attributed to acidifying effects of organic acids and/or the
increased permeability and leaching of salts. Even so, it is noteworthy that even
though there was a decrease in pH, the change was very slight from 7.15 to 7.08 and
7.14 to 6.97 in clay loam and sandy loam soil, respectively, still maintaining the soil
pH values at neutrality.
18.6.2 Soil Physical Properties
Vermicompost application in soils mainly modifies physical properties such as the
water holding capacity, structure, porosity, aeration, infiltration and resistance to
erosion. Aeration, water retention and improved soil structure are naturally
influenced by soil aggregate stability. Aggregate stability is influenced by polysaccharides from organic matter, which can act as cementing agents between soil
particles in the soil (Mupambwa and Wakindiki 2012). Vermicompost products have
been reported to be also enriched with polysaccharides, which could have an
influence in aggregate stability when applied in the soil (Lim et al. 2014).
Parthasarathi et al. (2008) observed increased porosity in clay-loam and sandyloam soils amended with vermicompost, and the increased porosity was also attributed to the presence of polysaccharides in vermicompost. The increased porosity in
the study subsequently resulted in improved water holding capacity in soils with
vermicompost at 100% relative to soils without vermicompost.
318
H. A. Mupambwa et al.