Biochar: Miracle or Gimmick?

Biochar-and-Pyrolysis_1

Cornell University illustration showing biochar as a means of sequestering greenhouse gases.

I’m always skeptical of what I call the “notions and potions” school of gardening. Every few years there is some new substance touted as the secret to a lush vegetable garden. One such substance is biochar, a kind of charcoal used as a soil amendment.

The University of Minnesota Extension service is in the midst of a four year study to test the use of biochar in vegetable gardens.

Preliminary results (which you can read here) show benefit for some crops such as kale, but a decrease in growth for others such as asparagus.

The more we learn about biochar, the more we need to learn. From an overall standpoint, there appeared to be some benefit of using biochar in the nutrient-depleted sandy soils at the Andover site for some crops. Yet, there was a decrease in growth in some plants and higher yield in others. In the Arboretum and St. Paul campus sites, we noted similar results, but more crops seemed to decline with biochar than without it.

There’s nothing new about biochar. It was in use by native peoples in the Amazon region before Columbus. Hopefully this study will help clarify what types of soils and what crops benefit most from its use.

Do you have an opinion about Biochar? Leave a comment . . .

And thanks to Michael Tortorello for sending me the link.

Straw Bale Garden Part IV: Almost Ready to Plant?

straw bale garden

Over the past fifteen days I’ve been “conditioning” my straw bale garden by adding blood meal and a lot of water. During the conditioning process we had both a freak rainstorm (helpful) and a freak heatwave (not so good).

The bales did not heat up as much as I expected–as of this morning they are around 80° F, around 15° to 20° higher than the ambient temperature. Several sources I checked, however, suggest that this is hot enough. The test will be when I plant seedlings. If they end up stunted, I’ll know that I did not let the bales compost long enough.

One problem I had with the conditioning process is that the straw on most of my bales was oriented with the stem sides facing the wide (vertical) side of the bale. This made it difficult to get the blood meal into the bales. One or two of the bales had the straw oriented with the stems facing up and these bales seemed to heat up faster.

Another problem was keeping the bales moist in our hot and dry climate. Tarps may have helped.

The next step will be to plant seedlings and add a balanced fertilizer (fish emulsion) every other week.

Compost and Pharmaceuticals

happypills

We get this question a lot–will pharmaceuticals end up in my compost if I use human urine or animal manure? This is really three questions:

  • Does composting break down pharmaceuticals?
  • Are some pharmaceuticals worse than others in terms of their ability to survive the composting process?
  • If pharmaceuticals persist after composting do edible plants uptake them in sufficient quantities to effect humans?

A look at what science has to say
We really need a Root Simple research department! I was able to find a few studies that, at least partially, address these questions. If you know of more please leave a link in the comments.

A 2010 study looked at the degradation of salinomycin, used on chickens to prevent coccidiosis. The study concluded,

On the basis of the results obtained in this study, it appears that the composting technique is effective in reducing salinomycin in manure.

Another 2010 study looked at the composting of sewage sludge containing fluoroquinolones (broad spectrum antibiotics),

The concentrations of pharmaceutical residues in compost were significantly lower, if compared to the relevant concentrations in sewage sludge . . . It is concluded that before using the sewage sludge compost as a fertilizer it should be carefully tested against the content of different pharmaceuticals. The content of pharmaceuticals in the compost made from sewage sludge may easily lead to the elevated concentrations in food plants, if the compost is used as a fertilizer.

A slightly contradictory Estonian study concluded:

In the current study, uptake of ciprofloxacin, norfloxacin, ofloxacin, sulfadimethoxine and sulfamethoxazole was demonstrated in lettuce. The uptake of fluoroquinolones and sulfonamides by plants like lettuce does not seem to be a major human health risk, as the detected levels of the studied pharmaceuticals were relatively low, if compared to their soil concentrations. Further studies are needed to determine the uptake of different types of pharmaceuticals and other organic pollutants by various crop plants.

What about hormones? A paper in the Journal of Environmental Quality concludes,

composting may be an environmentally friendly technology suitable for reducing, but not eliminating, the concentrations of these endocrine disrupting hormones at concentrated animal operation facilities.

But we’ve got a lot of hormones making their way into the environment due to agriculture, according to a study done by Temple University,

Animal manures (poultry manure and cow manure) contribute to a significant load of estrogen hormones in the natural environment.

Conclusions
Clearly we may have some big societal problems caused by the overuse of pharmaceuticals and waste generated by industrial livestock operations. Those issues are beyond the scope of this blog.

But what about home composting? Should I pee on my compost pile if I’m on lots of pills? Maybe not. But I think there are a few common sense guidelines we can follow when working with human and animal urine or manure at home:

  • Don’t use municipal compost that is made with sewage sludge, though I’m more worried about heavy metals in that compost more than I am about pharmaceuticals.
  • Since I’m not on any pharmaceuticals, I’m not worried about my own urine in the compost pile.
  • Joel, who commented on an earlier Root Simple post about using urine in compost, had this to say, “The main thing I’d worry about is radionuclide therapy, such as treatment with radioactive iodine vs. thyroid cancer. I guess I’d also worry a little about people who are on chelation therapy to flush toxic heavy metals from their system. If it’s not concentrated enough to harm your kidneys, though, I’m thinking it’s not enough to worry about in soil…perhaps that is me being naive.”
  • If I were collecting pee soaked straw bales at a French heavy metal concert (unlikely!),  I might have the resulting compost tested if I were going to use it on vegetables. But composting those bales would be better than flushing all that urine down the sewer system.

As to the bigger environmental issues, the good news is that some of the research shows that composting can help reduce pollution. And, since some of us have the space to compost at home, we can all contribute to a cleaner planet.

What do you think? Leave a comment . . .

Straw Bale Garden Part III: Adding Fertilizer

watering fertilizer into a straw bale garden

After watering our straw bales for three days our next step is to apply a high nitrogen fertilizer. We’re following West Virginia University Extension Service’s Straw Bale Gardening advice. They suggest a 1/2 cup of urea per bale or “bone meal, fish meal, or compost for a more organic approach.” (I think they mean blood meal as bone meal does not have much nitrogen in it.)

Choosing the organic approach, we’re watering in two cups of blood meal a day to each bale for days four to six. Days seven through nine, we’ll cut back to one cup of blood meal per bale. By day ten the bales should be almost ready to plant.

Once the bales are conditioned I’ll need to add a balanced organic fertilizer to provide potassium and phosphorous. And I discovered that taking the time to level the bales prevents fertilizer from running off when you’re trying to water it in.

Fertilizer Issues
Buying a high nitrogen fertilizer, even an organic one, is a bit of a conundrum. I object to chemical fertilizers, like urea, on philosophical grounds, but blood meal, a byproduct of our industrial food system, doesn’t make me feel much better. Urea would be a lot cheaper.

Perhaps the best solution would be human urine. Throw a week-long party, serve a lot of beer and invite your guests to fertilize your bales! Undiluted human urine has an NPK ratio close to that of blood meal.

Those of you who have experimented with straw bale gardens please leave a comment on what fertilizers you used and how it worked . . .

A Straw Bale Urinal

straw bale urinal

L’Uritonnoir, a plug-in straw-bale urinal. Photograph: Faltazi

At the risk of becoming a blog entirely about urine and straw bales, Anne Hars alerted me to an article in the Guardian, “L’Uritonnoir: the straw bale urinal that makes compost from ‘liquid gold’” about French design studio Faltazi’s plug-in straw bale urinal.

The device comes as a flat polypropylene sheet, which is folded into shape and slotted together, then threaded on a looping band around the bale, its funnel wedged deep into the centre of the straw to channel the fluid to the composting core. A deluxe version is also available in stainless steel – presumably for the VIP bale urinal area.

L'uritonnoir by faltazi

According to the article, Faltazi’s straw bale urinal will debut this summer at the French heavy metal festival Hellfest.

Ladies will have to pack their funnels.