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| Authors: | C. Gimenez, E. Diaz, F. Rosado, A. Garcia-Ferrer, M. Sanchez, M. Parra, M. Díaz, F. Peña |
| Keywords: | nitrogen fertiliser, nitrate leaching |
Abstract:
A survey was carried out during 1997-98 in the provinces of Malaga and Granada in southern Spain, to provide information about farming practices with a high risk of nitrate contamination of groundwater.
The regions were considered to be vulnerable to nitrate contamination on account of the intensity of agricultural production.
The total combined area was 345,000 ha.
The agricultural systems within these regions were characterised by conducting surveys of cropping and management practices on individual farms; farmers and extension personnel provided data.
Within the provinces of Malaga and Granada, 408 and 273 surveys were conducted, respectively.
Additionally, soil samples were taken at an approximate density of one sample per 900 ha.
Samples were taken at 0-30, 30-60, and 60-90 cm depth, to assess inorganic N in the soil profile at the beginning and end of the cropping season.
Most soil samples in both areas had high levels of inorganic nitrogen, suggesting a high risk of groundwater pollution.
The average values of soil inorganic N content in 0-90 cm profiles were 173 and 232 kg N ha-1 in Malaga and Granada, respectively.
Dryland cereals, some horticultural crops and sugar cane were the crops with the highest potential for nitrate contamination of groundwater.
The risk of nitrate contamination from olive orchards was moderate.
As a result of this work, a Code of Good Agricultural Practice has been prepared and is expected to be implemented in the near future.
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