Biochar + An Unusual Fertilizer

Our test plots are showing good results! The finger millet we planted in mid-April is growing well, and the biochar planted there is demonstrating its positive impact on plant growth.

The test plots that combine biochar with one of the organic fertilizers – a 15% solution of human urine – are doing exceptionally well. On a daily basis, visitors are shocked to see that the healthiest-looking test plot, with regard to both height and color, is the test plot that combines the human urine fertilizer with a biochar application rate of 6 tons/acre. It currently outperforms all of the other 18 test plots, including those with equal amounts of biochar and traditional chemical fertilizer.

Although “gross” at first glance, human urine is getting more recognition in popular media and scientific circles as a viable fertilizer. PopSci, Scientific American and The Washington Post have all written about a favorable study in Finland that experimented with a urine fertilizer on vegetables. The always dependable Wikipedia also offers some reading material on the use of human urine as a fertilizer.

Obviously, human urine is a very renewable resource. Instead of causing eutrophication in bodies of water or simply being flushed/latrined away as waste, there is growing evidence that it can act as a viable fertilizer alternative. If adopted in poorer areas of the world where purchased inorganic fertilizer constitutes a farmer’s largest single purchase of the year, large cost savings can be earned.

Perhaps most striking about our re:char biochar-human urine test plot is its contrast to a similar test plot: the one that uses the same amount of urine fertilizer but no biochar. The two photos below offer visual proof.

The test plot that uses a human urine solution as fertilizer but does not include biochar. (Our German colleague spells "urine" a little differently!) The height of the finger millet is 23 inches.

The height of the finger millet test plot that uses urine fertilizer + 6 tons/acre of biochar is 39 inches. That's 16 inches, or nearly 70%, higher than the urine test plot without any biochar!

We have four test plots that use a controlled amount of urine fertilizer and varying amounts of biochar: 0 kg/acre, 400 kg/acre, 2 tons/acre and 6 tons/acre. With each successive amount of biochar, growth improves, culminating in the test plot with 6 tons of biochar per acre. This biochar stuff is for real!

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