Nitrate data suggests 'a corner turned'

Nitrate levels are looking better in Southland
Nitrate levels are looking better in Southland

Environment Southland's latest water quality report shows a trend of decreasing or indeterminate nitrogen levels and Southland farmers deserve a pat on the back for this, Agribusiness farm consultant Deane Carson says.

Nitrate levels in Southland had always been an area of significant concern for him, and for a while were somewhat out of control, he said.

But the latest report showed the majority of the sites were indeterminate for nitrite­nitrate nitrogen (NNN) levels over the five years covered and nine of the 49 sites had a decreasing trend.

"That is a big, big change. That was the contamination that has been the big concern. . .My point of view is that is fantastic news for the region. There's still a lot more that can be done, but it's fantastic news," Mr Carson said.

It was all well and good challenging farmers to work hard to look after waterways and make improvements, but he believed they also needed to be rewarded for the work they were putting in, Mr Carson said.

"There's a lot of hype around intensification, but this [the report] would suggest that there has been a corner turned in Southland. I see a lot of activity, a lot of hard work and a lot of money spent . . .There's a lot of fencing and a lot of planting and a lot of work done by farmers and a lot of behavioural change."

The big news was the change in trend for NNN, as for a long time the opposite was happening, he said.

"The 17-year trend emphasises this. Forty-three percent were deteriorating. It's a major shift. Pat on the back to farmers, you've done a great job."

Environment Southland environmental scientist Roger Hodson said if the emerging trend of decreasing nitrate levels continued in Southland, it would be a positive sign.

He said it was common for fewer trends to be detected from shorter time periods, due to the smaller size available for statistical testing.

"The longer time-period trend analysis [17 years] shows that nitrate levels are increasing at nearly half [43%] of monitoring sites, with two sites showing decreasing trends.

However, in contrast, the short five-year time period shows there is some evidence of a change in direction, with nine sites showing a decreasing trend, two showing an increasing trend with the balance being indeterminate."

The data in the report looked solely at the physical and chemical characteristics of fresh waters, not at ecosystems.

- Otago Daily Times

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