Estimation of nitrogen load at sugarcane cultivation areain northern Negros Island, the Philippines

Abstract

Sugarcane mono-cropping is distributed in northern Negros Island. Due to the high permeability of the underlying limestone, it has high possibility that nitrates derived from nitrogen in fertilizers, human and animal waste can easily leach to underground and cause high nitrogen load. Nitrogen load to ground surface from each nitrogen sources and that to groundwater was estimated using statistical and survey data by unit load in this study. About 80% of this area was for sugarcane cultivation, and more than 80% of nitrogen load was from nitrogen fertilizer for sugarcane cultivation. According to nitrogen balance in this area, 40-50% of nitrogen load to ground surface consist of that to underground. It will be necessary to consider the fertilizer management to reduce nitrogen load in this area, such as reduction for amount of nitrogen fertilizer application or application timing of nitrogen fertilizer in sugarcane cultivation.