Abstract:
The study was focused on estimation of nitrate-N in groundwater and soil in intensive agricultural
areas mainly on Valikamam East, Jaffna, Sri Lanka. Groundwater samples from sixty eight wells were collected
from the intensive agricultural areas and an analysis was done periodically from July 2007 to February 2008
throughout dry and wet season for nitrate-N concentration. Out of sampled area, some of the areas were selected
for soil sampling to see the nitrate level in the soil. Nitrate-N in the groundwater and soil was determined by
brucine method. The nitrate- N vary in all the months in sixty eight wells and values were ranged from 0.1mg/l
to 17.83 mg/l. Out of sixty eight tested wells, 80% of the wells were not recommended for drinking water in
intensified agricultural areas and all the wells were accepted for irrigation requirement. High concentration of
nitrate-N was observed till 0- 40 cm of soil profile and the concentration was low below the top layer. There was
a good correlation between soil nitrate-N to groundwater nitrate-N.
