| nitrate pollution in groundwater and strategies to reduce pollution. | the input-intensive rainfed tropical ecosystem, where wet season (ws) rice (oriza sativa l.)-dry season (ds) diversified high-value upland crops like vegetables predominate, has resulted in a problem of a large leakage of n into the environment, thereby polluting the water. excessive use of n fertilizer in high-value crops grown in ds is economically motivated. out of twenty water sources evaluated in a watershed with a total area of 265 ha located in magnuang, ilocos norte, philippines, twelve ... | 2002 | 12079116 |