| Summary: | The global demand for agricultural cropland due to population growth and loss of
prime cropland to soil erosion and urbanization has led to increases in chemical fertilizer
usage in order to increase the yield per unit area. But this has not been without a price.
Chemical fertilizers, apart from their high costs, are known to cause water pollution to both
surface and subsurface water bodies. To mitigate this problem, research has been focused
on the application of animal manures and composted material to land to improve the quality
of some poorly drained soils.
In this study, composted swine manure was manually mixed with a poorly drained soil
sample collected from Boundary Bay Water Control project site to enhance its drainage.
The soil plus compost mixture was introduced into clearcast acrylic tubes. Five of the tubes
with soil alone control tube were set inside the Laboratory and the other five tubes with a
control were situated outside to simulate field conditions. The tubes were fertilized with
different concentrations of liquid swine manure and chemical fertilizer to supply the
necessary nutrients required by plant. Enough water was applied to saturate the sample
based on the soil water storage capacity from a previous experiment. Leachate samples
were collected and analyzed for some selected water quality criteria (pH, electrical
conductivity (EC), ammonia-N, nitrate + nitrite-N, and total Kjeldahl nitrogen).
The pH, EC, ammonia-N, and nitrate + nitrite-N did not show any significant
increase with the increased rate of liquid swine manure or chemical fertilizer application.
In fact, the soil plus compost alone mixture may contain enough nutrients that extra
fertilization was not necessary. Hence, the composted swine manure can be used as an extra
source of nutrient and to enhance the soil hydraulic properties. Water pollution from these
applications was minimal based on the experienced conditions.
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