Avoiding nitrates

[Bruce14]

I know there aren't any firm guidelines about cutting feed after a frost and that testing for nitrates should be done. But what are the general times to cut. 1-2 days after or else wait for ten days? How quickly after a frost will the plant have nitrate uptake? Looks like tonight will be our first hard frost this month.

[chalmers]

Usually this late in the year the recommendation is to cut feeds ASAP after a frost and then test the resulting feed for nitrates prior to feeding to livestock. The reason for cutting ASAP after frost is the roots are not damaged by a frost so they continue to take up nitrates but the upper part of the plant is damaged so its capacity to convert those nitrates to protein is diminished hence the nitrates accumulate in the plant. Those nitrates will only go down if the plant recovers and starts new growth which will utilize the nitrates, but they will never go down to 0. This late in the year, the regeneration of new plant growth is minimal, and your losses by the plant (quality) due to the frost (i.e . leaves) is usually great, hence the recommendation to cut ASAP. If this was July and new growth potential was greater then perhaps you might want to wait for growth to reduce the nitrate levels depending on the severity of the frost, stage of crop etc. Check out Alta Ag. article on nitrates which explains the options at http://www.agric.gov.ab.ca. Hope this helps.

[chalmers]

A little known secret about nitrates is that you can silage it in a bag (oxeygen free fermentation) and convert the nitrates to something useful.