Seems as if the recent "dialog" about pee in the garden has scientific merit, despite the qualms of the squemish and .... whatever.
Second article of research follows this one.
Wow, I gotta go take a ... you know.
Charlie
Check out the article for active links...
According to a study from a group of environmental scientists at the University of Kuopio in Finland, human urine and wood ash make a reasonably potent tomato fertilizer, boosting plant growth and fruit yield dramatically over untreated plants and nearly keeping pace with conventional fertilizer. The research appears in the August 26 Journal of Agricultural and Food Chemistry.
The idea did not come completely out of left field?urine and ash have individually found use in helping plants grow, and their beneficial aspects appear complementary on paper. A commonly used nitrogenous fertilizer called urea is prevalent in urine, and wood ash (the Finnish group used birch) is rich in nutrients, such as potassium and calcium, that urine lacks.
In the greenhouse test, urine alone actually produced more tomatoes than urine with ash did?and neither treatment produced quite as much as did the researchers' mineral fertilizer. But both urine-based fertilizers roughly quadrupled fruit production when compared to unfertilized control plants. The researchers estimate that the product of a single individual's micturition could fertilize 6,300 tomato plants a year, yielding more than two tons of fruit.
The addition of ash did confer some benefits?those plants were larger and grew fruit with significantly higher magnesium and potassium content. A panel of 20 taste testers rated all growing methods as equally tasty.
Some caveats, remain, of course. The urine in the Finnish study was stored in cool conditions for six months before use, and it is unclear what effects this had on its fertilizing properties. What is more, plants are often highly salt-averse, and it seems reasonable to think that the salinity of urine could be harmful at high enough doses.
Then there's the inevitable gross-out factor: The researchers caution that even though urine is usually free of the harmful microbes found in fecal matter, care should be taken to avoid direct contact between urine-based fertilizer and the plants themselves to prevent contamination.
Also: see page for full reference
- Abstract * HTMLFull Text HTML * PDFHi-Res PDF[773 KB] * PDFPDF w/ Links[750 KB]
Surendra K. Pradhan*, Jarmo K. Holopainen and Helvi Heinonen-Tanski Department of Environmental Science, University of Kuopio, P.O. Box
1627, FI-70211 Kuopio, Finland J. Agric. Food Chem., 2009, 57 (16), pp 7612?7617 DOI: 10.1021/jf9018917 Publication Date (Web): August 3, 2009 Copyright © 2009 American Chemical Society *Corresponding author (e-mail snipped-for-privacy@uku.fi; telephone +358 403553169; fax +358 17 163191). AbstractThis study evaluates the use of human urine and wood ash as fertilizers for tomato cultivation in a greenhouse. Tomatoes were cultivated in pots and treated with 135 kg of N/ha applied as mineral fertilizer, urine + ash, urine only, and control (no fertilization). The urine fertilized plants produced equal amounts of tomato fruits as mineral fertilized plants and 4.2 times more fruits than nonfertilized plants. The levels of lycopene were similar in tomato fruits from all fertilization treatments, but the amount of soluble sugars was lower and Cl- was higher in urine + ash fertilized tomato fruits. The ?-carotene content was greater and the NO3- content was lower in urine fertilized tomato fruits. No enteric indicator microorganisms were detected in any tomato fruits. The results suggest that urine with/without wood ash can be used as a substitute for mineral fertilizer to increase the yields of tomato without posing any microbial or chemical risks.