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Nitrate concentration of groundwater and its association with livestock farming in Miyakonojo Basin, southern Kyushu, Japan
Author(s) -
Sugimoto Yasuhiro,
Hirata Masahiko
Publication year - 2006
Publication title -
grassland science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.388
H-Index - 19
eISSN - 1744-697X
pISSN - 1744-6961
DOI - 10.1111/j.1744-697x.2006.00044.x
Subject(s) - nitrate , groundwater , livestock , structural basin , environmental science , water quality , hydrology (agriculture) , agriculture , nitrogen , zoology , environmental chemistry , geography , ecology , chemistry , forestry , biology , geology , paleontology , geotechnical engineering , organic chemistry
Nitrate concentration of groundwater was surveyed in 741 wells in 10 districts in central Miyakonojo Basin, southern Kyushu, Japan, to determine the nitrate status in the region and to examine its association with livestock farming. Nitrate‐N concentration averaged 5.4 mg L −1 , with 13% of the wells exceeding the maximum contaminant level (MCL) for drinking water (10 mg L −1 ). Wells possessed by farmers had a higher maximum (48.6 versus 27.6 mg L −1 ), mean (7.4 vs 3.6 mg L −1 ) and percentage above the MCL (23 versus 5%) than those possessed by nonfarmers. Occurrence of nitrate in groundwater varied not only with the ownership of wells but also among the districts (mean nitrate‐N concentration = 3.0–8.6 mg L −1 , percentage above the MCL = 0–32%). The mean nitrate‐N concentration of individual districts was positively correlated with both excretal nitrogen output from livestock ( r = 0.725, P = 0.018) and excretal nitrogen load to farmland ( r = 0.864, P = 0.001). The results show that groundwater quality in central Miyakonojo Basin was considerably deteriorated mainly in farmers’ wells, with livestock farming as a responsible source of nitrate contamination.