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Roy, et al.

water infiltration and storage, irrigation and drainage, department’s experimental field (22°27’58” N 91°46’49”
nutrient and pollutant leaching, runoff and catchment E) of the Chittagong University. Samples of soil were
management, and the potentiality of soils with regard taken between 0 and 15 cm below the surface. Following
to productivity all depend on the saturated hydraulic collection, samples were broken through gentle crushing
conductivity (Ks) of the soil. 2,14,15 The Ks is influenced by with a wooden hammer and allowed to air dry. The
soil properties, soil depth, vegetation types, management samples of soil were then passed through a 2 mm
practices, and so on. 16-19 Among the physical indices, stainless steel sieve. The sieved samples were kept for
the saturated Ks change with soil texture, geometry the purpose of analyzing the soil’s chemical and physical
of soil particles, porosity, and bulk density. 20,21 It is characteristics. 25,26 Bulk vermicompost was collected
noteworthy that different management approaches and from an organic farm, air-dried, and sieved to separate
the incorporation of organic amendments have been into different size fractions, namely, raw, 1.0 – 2.0 mm,
shown to affect the saturated Ks of soils. 2,22,23 However, 0.5 – 1.0 mm, and <0.5 mm. Figure 1 shows different
the saturated hydraulic conductivity and other hydraulic size fractions of vermicast used for this experiment.
properties of soils seem to be significantly impacted by To set up the experiment, 100 g (on oven dry weight
the variability of particle size distributions. Both the basis) of 2 mm sieved soil samples were weighed. Then,
distribution of soil particle sizes or soil texture and the the required amount of vermicast of different size ranges
spatial arrangement of these particles or soil structure for the rates of 5 t/ha, 10 t/ha, 15 t/ha, and 20 t/ha were
affect the Ks values. 24 weighed and thoroughly mixed with the previously
At present, there is a paucity of knowledge regarding weighed soil samples. The incorporation of vermicast
the link between vermicast size and Ks. Although the resulted in five different treatments for each soil type.
effects of soil texture and types of organic manure on The treatment arrangement comprising different sizes of
Ks of soils have been studied separately, to the best of vermicast is shown in Table 1. For every experimental
the author’s knowledge, none of the previous research condition, we compared the results and treatments with
manifests the effects of vermicast size on the Ks, and a control setup and performed a reasonable number of
how cast sizes affect conductivity in different textural replications (Table 1).
classes of soils. Therefore, this study investigates the After mixing up the soil and vermicast of different
impact of adding different size fractions of vermicast on sizes independently, the samples were packed in the
the Ks of two distinct soil types and clearly illustrates aluminum core (4 cm in height and 5.6 cm in diameter),
how the various vermicast sizes affect the saturated maintaining a roughly uniform bulk density. Amended
hydraulic conductivity. and controlled soils inside the cores were initially
subjected to wetting from the bottom. After complete
2. Materials and methods saturation, distilled water was passed through the soil-
filled cores. By maintaining a constant water load, the
The soil samples for this investigation were collected Ks were determined by measuring the volume of water
from two distinct, undisturbed locations on the campus passing through the soil column. The amount of water
of Chittagong University that differed widely in terms passed through the soil column was measured using
of soil texture. From the field next to Ansar camp a measuring cylinder, and the data were recorded to
(22°27’56” N 91°46’46” E), loamy soil was collected, calculate Ks. The Ks of both soils was calculated using
25
and sandy loam soil was taken from the soil science the following formula:

Figure 1. Different size fractions of vermicast

Volume 22 Issue 1 (2025) 116 doi: 10.36922/ajwep.7526