| Abstract: | SUMMARY The impact of cropping systems on water quality is uncertain, and its interpretation depends heavily upon our definition of acceptable risk. As a means of determining net effect, both classical and precautionary approaches to assessing risk have their strengths and weaknesses. Relating the impact of cropping practices to human health outcomes can be particularly difficult. A variety of guidelines and standards are used to assess water quality, and recent methods for assessing water quality seek to incorporate more than water chemistry alone. An understanding of the derivation of water quality guidelines and standards is essential to their effective application, and meaningful interpretation. In addressing water quality concerns, it is essential to first clarify that there is indeed a problem, and whether agriculture makes a significant contribution. Compound interactions and modes of chemical movement can render this troublesome. Yet, because farmers live on the land and drink the water, they want to be among the first to know what is happening and to take appropriate action when problems are identified. Agriculture must be proactive in addressing water quality concerns. However, effective land management strategies depend greatly upon regional differences and may be highly site-specific. Hence, it is best to apply a set of common sense concepts at the local level. Because soil and water degradation are closely related, practices first developed to help conserve the soil (i.e., crop rotations, reduced tillage, cover crops) may also tend to conserve water quality. As well, restricting the loss of agricultural inputs (e.g., fertilizer nutrients, pesticides) from off farmland, and reducing the amount of those that might be available to do so, can assist in effectively reducing potential pollution. Buffer zones are a promising means of using plants and wetlands as a filter towards intercepting escaping contaminants. |
