Nitrate-nitrogen concentration variationin groundwater flow in a paddy field

Abstract

This study was carried out to evaluate the influence of groundwater on nitrate-nitrogen concentration in a paddy field. Fertiliser if applied excessively can cause leaching into the soil and will penetrate deep into the soil and eventually contaminate the groundwater. Nitrates in groundwater is soluble hazardous to users. This work was carried out at Ladang Merdeka Ismail Mulong, Kota Bharu, Kelantan to determine groundwater and nitrate-nitrogen flow using ArcGIS in a Geographical Information System (GIS) environment to produce groundwater level and nitrate concentration variation maps. All data were obtained from field measurements. The results showed that the average nitrate level was 4.81 mg/l with a maximum value of 17.16 mg/l. The groundwater levels in this area ranged from 3.75 to 6.52 meters above mean sea level with an average of 5.65 meters. Three dimensional images of ground surface and groundwater levels variation were also produced to study the relationship between groundwater and nitrate movement. From the analysis, it can be deduced that the groundwater and nitrate generally flows from the South-West to the North-East direction following the ground surface gradient.