Science - Excess nitrates in water would benefit crops

Toronto, Dec 4 (IANS) High nitrate levels in water makes it unfit for drinking, but it would benefit crops, according to a study.

Texas AgriLife Research scientists John Sij, Cristine Morgan and Paul DeLaune have studied nitrate levels in irrigation water and aquifers over the past three years.

'When you get more than 10 parts per million (ppm), it exceeds the... limit,' Sij said. 'Our water (at Chillicothe) is around 20 parts per million, so we don't give it to the babies, but adults can drink it.'

'We don't know what percentage of the nitrate is geologic in nature or what percentage is due to farming operations,' Sij said. 'But if we take it into consideration in our fertility programs, we can mine the nitrogen and use it as a resource,' according to Texas AgriLife release.

Mining the water for nitrates, instead of putting in additional and sometimes unnecessary nitrogen, may also have the potential to improve water quality from the Seymour Aquifer, he said.

Assuming a 20 ppm nitrate concentration and just 12 inches of applied irrigation water per acre over the growing season, approximately 20 kilos of usable nitrogen per acre can be applied to a cotton crop, DeLaune said.

Of course, other nutrients like potassium and phosphorous must be adequate to take advantage of nitrates in the irrigation water as well as any applied fertiliser nitrogen, he said.