The Great Urination Event and other tales of the Nitrogen Cycle (with a note on why Earth Needs More Mulch)

by Liam Heneghan

Several years into my first large-scale field experiment, I noticed one of the technicians urinating on my experimental plot. It was a significantly worse event than when a cow inserted a hoof into one of my mesocosms in an adjacent part of the Co Kilkenny spruce plantation where I was working. The bovine mesocosm disaster was relatively inconsequential. The mesocosm was an isolated fragment of soil surrounded by PVC walls, open on top and with a collecting vessel below; it allowed me to examine the flow of nutrients through the earth. The hoof merely took one hoof-sized replicate of many out of play. The urination event was more significant; we might have to consider bottling his nitrogen-rich fluid for later analysis and factor it into the work. The technician and his urine had become an experimental treatment, quite an anomalous state of affairs. Gents

The field experiment was a long-term evaluation of the effects of chemical additions, including nitrogen, on soils in a Kilkenny spruce plantation. After a brief interrogation about the technician’s en plein air habits, we were confident that, though several patches of the forest had enjoyed the benefits of his impromptu fertilization treatments, it seemed unlikely that the experimental plots had done so more than on this one occasion. A back-of-the envelope calculation confirmed that this small nitrogen addition was insignificant compared with the 150 kgs of nitrogen per hectare that we were adding to these plots annually.

Although the minor urination event, it turned out, was rather non-calamitous, my fieldwork was related to an investigation of a larger nitrogen calamity: a global experiment that I will call here the Great Urination Event (GUE), which has significant effects on biological diversity, on soil and water quality, and on human health.

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