Growing season | Low risk (<2500 mg NO3 kg−1) | Moderate risk (2500 - 4500 mg NO3 kg−1) | High risk (>4500 mg NO3 kg−1) | |||
2003-2006 | 0.802 | ±0.0159 | 0.115 | ±0.0063 | 0.082 | ±0.0086 |
2007 | 0.656 | ±0.0602 | 0.184 | ±0.0213 | 0.160 | ±0.0342 |
2008 | 0.757 | ±0.0549 | 0.138 | ±0.0231 | 0.105 | ±0.0251 |