Idiot/Savant, commenting on the threat posed to Christchurch’s drinking water from agriculture, wrote today:
“Basically, its us or the cows. That’s the stark choice we are looking at. And put like that, there can be only one answer: the cows have to go, or be regulated to within an inch of their lives to prevent them from being a threat to ours.”
I don’t know if this is theatrical hyperbole or literal forecast. Dairy farming certainly poses current and future threats to water supplies and waterways, and as such would need to be managed, but I don’t see an either/or dichotomy. I drink milk – both cow and soy – though more out of habit than any nutritional requirement since calcium can be readily obtained from non-diary sources. I eat cheese – typically the snootier varieties – and my quality of life would definitely drop if I had to sustain a cheese drought. I also drink Christchurch water, untreated, from the Canterbury Plains aquifers.
What seemed to spur I/S to this remark is the observation that we are “increasingly drinking cowpiss”. Artistic licence this time, I’m sure. It comes via coverage of Russell Norman’s visit to eutrophic Lake Ellesmere, and the quote therein:
“A GNS scientist said last year a 200-metre deep well in Avonhead had shown a “statistically significant trend” in increasing nitrate-nitrogen concentrations since 1995.”
The GNS scientist in question is Paul White. His comments came from evidence he gave last year regarding the Central Plains irrigation scheme [PDF]:
“A 200.2 m deep National Groundwater Monitoring Programme well located near Avonhead has recorded a statistically significant trend (with a rate of increase of 0.006 mg/L/yr) in nitrate-nitrogen concentrations since the NGMP began sampling the well in 1995. This rate of increase is low, but the increase indicates the potential of intensifying land use to impact on Christchurch groundwater quality. Groundwater quality in the 200.2 m deep well is good; median nitrate-nitrogen concentration is 0,24 mg/L, and the median oxygen concentration is 6.3 mg/L, of samples taken since 1995.”
This trend does not pose a health risk, but could very well be an indicator of the reach of agricultural pollution.
In any case, it is the pollution that is the problem, not the cows. More intense dairying would likely lead to worse water quality all else being equal, but there is no need to assume all else will be equal. In conjunction with regional planning to limit the extent of dairying, there is room for on-farm management practices to improve. The question is both how many cows and how to manage them.