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Diffuse Nitrogen Load Pollution from Collective Tea Field-Case in Makinohara Plateau, Shizuoka Prefecture-

2006; Japan Society on Water Environment; Volume: 29; Issue: 11 Linguagem: Inglês

10.2965/jswe.29.745

1881-3690

Tomihisa YAMAMOTO, Hideo Nakasone, Hisao Kuroda, Tasuku Kato,

Soil and Water Nutrient Dynamics

The authors measured the nitrate concentration of river water from a catchment basin of the collective tea fields in the Makinohara plateau in Shizuoka prefecture, from June 2002 to May 2003. About 1,000 kg · ha-1 · y-1 of nitrogen fertilizer has been used in the tea fields for about 30 years. The annual average NO3-N concentration and pH were 24.4 mg · l-1 and 4.9, respectively. NO3-N concentration decreased as a result of a comparatively small amount of precipitation, and repeated. The total annual nitrogen outtlow from the tea fields was 428 kg · ha-1 · y-1. The ratio of nitrogen load to the amount of applied nitrogen fertilizer was 79.2 %. NO3-N load was affected by discharge from the tea fields.