The impact of nitrogen fertilizer on the aquatic environment in the Upper Tondano watershed, North Sulawesi Province

Nitrogen fertilization is needed as a source of nitrogen in the growing plants. Nitrogen in the environment will undergo a transformation in the form of compounds such as nitrate (NO3−) and nitrite (NO2−). The transformation from nitrogen to nitrate, nitrite, will have a negative impact on the aquatic environment namely the formation of toxic conditions. The main purpose of this research was to study the residual nitrogen fertilizer in the outlet of paddy irrigation upper Tondano Watershed and to evaluate the residual nitrogen fertilizer in the outlet of paddy irrigation upper Tondano Watershed 5-years period (2015-2019). Water quality sampling was carried out using a composite sampling method at two sample locations in River Panasen, in situ measurement of water temperature parameters, and pH. Analysis of the parameters of nitrate and nitrite was carried out in the laboratory. Data were analyzed using descriptive statistics. The results showed that the concentration nitrate of -0.9330-153 mg/l (according Government standard PP No. 82/2001 nitrate 10 mg/l), and nitrite of 0.001 mg/l-0.52 mg/l exceed PP No. 82/2001 quality standard (0.006 mg/l).