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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/SWMR/10
Assessment of nitrogen mineralization pattern in soil upon application of urea and bio-
digestate

Sara Bano, Akhtar Iqbal*, Amna Akhtar, Farhan Hafeez, Rashid Nazir, Faridullah,
Muhammad Irshad
COMSATS University Islamabad, Abbottabad Campus, Department of environmental
sciences.
Correspondence: akhtariqbal@cuiatd.edu.pk

Abstract
With the rapid growth of global population and rising food demands, the agriculture sector is
bound to use greater quantities of fertilizers to increase the crop productivity. In light of steps
to substantially reduce the usage of chemical nitrogen by agriculture, urea is still widely used
fertilizer, since it offers the highest degree of low cost. The rising number of biogas plants
worldwide has led to increased bio-digestate production which is rich in nutrients with great
fertilization potential. At various stages of growth, plants demand different quantities of
nutrients. To reduce the dependence on chemical fertilizers and evaluate the fertilizing potential
of bio-digestates, this study was planned. This study was conducted to quantify nitrogen
contents and forms of nitrogen in bio-digestates (solid and liquid) and their mineralization
pattern in soil. Furthermore, this study focused on comparison of nitrogen mineralization
pattern between chemical fertilizer (Urea) and bio-digestates (solid and liquid) in two different
0
soils at a constant temperature (28 C). Both soils differed in terms of silt and sand contents.
Initial characteristics of bio-digestates differed in terms of organic carbon contents (higher in
solid bio-digestate), pH (higher in solid bio-digestate) and ammonium (higher in liquid bio-
digestate) contents. Soil organic carbon contents were reduced in control and urea treatments
as compared to bio-digestates treatments. Soil pH was increased for all treatments at day 15
then a decreasing trend was observed. More ammonium were observed in control as compared
to other treatments in both soils. Higher concentration of nitrates was observed in treatments
where urea and both bio-digestates were applied as compared to control treatments in both
soils. Cumulative mineral N contents were higher for urea treatment as compared to both bio-
digestates in soil-1. While in soil-2, liquid bio-digestate showed the maximum cumulative
mineral N contents as compared to other treatments.

Keywords: nitrogen; bio-digestate; mineral

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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