In a newly published study, researchers dug into how fertilizing with manure affects soil quality, compared with inorganic fertilizer.
Ekrem Ozlu of the University of Wisconsin-Madison and his team studied two fields in South Dakota. From 2003 to 2015, the research team applied either manure or inorganic fertilizer to field plots growing corn and soybeans. They used low, medium, and high manure levels, and medium and high inorganic fertilizer levels. They also had a control treatment of no soil additives to provide a comparison.
In the summer of 2015, they collected soil samples at a variety of depths using a push probe auger. Then they analyzed the samples.
- Manure helped keep soil pH—a measure of acidity or alkalinity—in a healthy range for crops. Inorganic fertilizer made the soil more acidic.
- Manure increased soil organic carbon for all the measured soil depths compared to inorganic fertilizer and control treatments. More carbon means better soil structure.
- Manure significantly increased total nitrogen compared to fertilizer treatments. Nitrogen is key to plant growth.
- Manure increased water-stable aggregates. These are groups of soil particles that stick to each other. Increased water-stable aggregates help soil resist water erosion. Inorganic fertilizer application decreased these aggregates.
Is it time to re-purpose the world's sewage into fertilizer?
(Score: 1) by shrewdsheep on Thursday November 01 2018, @03:25PM (1 child)
Any reference to back this up? Plants have very selective mechanisms of taking up molecules - they do not swallow stuff after all. To the best of my knowledge it has not been shown that drugs enter the food chain through plants.
(Score: 3, Informative) by Entropy on Thursday November 01 2018, @09:09PM
"..Five of the six test chemicals were taken up in detectable quantities into radish and ryegrass.."
Reference:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3908740/
That particular study used much lower concentrations in soil than previous studies to see if plants uptake the chemicals(drugs) at more "expected" soil concentration methods. I suspect if we were to dump human sewage onto crops regularly the concentrations might be quite a bit higher than the expected value in this study.
You'll find many other studies by searching for "plants uptake pharmaceuticals".
Thanks for asking for a reference. This is one of the more skeptical (lower concentration) ones around, and suggested the concentrations in leaf/beans/etc. did not pose a risk to humans consuming them. There are studies with more drastic results, though.