Happy Earth Day! (and, A Fun and Exciting Citizen Science Project!)

Happy Earth Day everyone!  Hope you're planning to get out and enjoy yourself some nature, make your little corner of the environment a better place, and maybe, save some frickin' trees like Tenacious D.

Along those lines, last weekend, we found ourselves trying to save some trees.  More specifically, trying to save our fruit tree blossoms, many of which decided to burst forth in glory right before an epic April Colorado blizzard. (Higher elevations saw close to 50" of snow, but we barely got a foot.)  In fact, every spring, we find ourselves wishing our fruit trees would bloom later so we wouldn't have to worry so much about fruitless years.

Yet another use for chicken feed bags. Not sure if it saved the flowers, but it definitely made the trees look ridiculous..

It turns out, we're not alone.  One of our favorite homestead bloggers has similar annual lamentations on her southwest Virginia homestead, and has been researching apple varieties that bloom later.  (It turns out that the bloom time is a function of the cultivar and depends on the number of hours the tree spends above 40 °F, after a chill period.)  Unable to find the necessary data from researchers in the ivory tower of academia (this paper has a good list, but features mainly commercial cultivars), Anna has started a Google spreadsheet to crowdsource the information.

Anna's Google spreadsheet: enter your fruit tree bloom times this spring!

This is where you, dear readers, can help.

Here's how it works, and it's super simple: click on the link above, and enter in your USDA growing zone (make sure to get the right one; some have changed in the last few years to reflect less frigid minimum winter temperatures), apple variety, and the date it reached full bloom.  Then, read through the other varieties and see which ones bloom after your last local frost or freeze date.  After that, you might want to get distracted for several hours reading about heirloom apple cultivars.

It's a short list so far, but together, we can help Anna make it the ultimate guide to frost-wise apple variety selection!  Thanks for organizing it, Anna!

Wild Greens Nutrition Comparison

You might be getting tired of all our posts this spring extolling the virtues of wild greens, but we wanted to do one more before giving it a rest for a while.  In particular, we were curious to see how the nutrition of the greens we forage stacked up against the greens we grow, so we made a spreadsheet (of course) to compare.  And as long as we were answering our own questions, we figured we might as well write it up into a blog post!

It's a bit of a challenge to get an apples-to-apples comparison because not all "weeds" have nutrition info readily available, and of the ones we were able to find, not all of the same metrics were available for each (for example, some were missing vitamin K or some of the B vitamins).  On top of that, some of the benefits of eating wild greens are attributed to factors that aren't quantified in normal nutritional analyses, such as content of phenolics, flavonoids, and mucilaginous substances. But, for what it's worth, we can make a few legitimate comparisons.

And fortunately, there's enough data to make some charts and graphs!

First up, Vitamin A.  Actually, first we should say that the reported serving sizes vary widely across our source materials (linked at the end of the post), so we had to do some normalization.  Everything here is based on 100 g of fresh leaves, rather than a one-cup serving.  But back to vitamin A: just about all of these greens will give you a good dose of it, but if you're foraging and feeling deficient, aim for dandelion, lambsquarter, and stinging nettle greens.  These three, along with kale, are well over the 100% RDV.  Interestingly, several sources claim that mallow is a good source of vitamin A, and although 28 RDV% is nothing to sneeze at, it hardly measures up to most of the other greens.

However, those same sources claim mallow is rich in vitamin C, and the only quantitative measure we could find put it at about 1% RDV. (Although the flowers have a lot more than the leaves.)  But it looks like we'll have to shoot for dandelion, sorrel, or lambsquarter greens if we catch the scurvy and there's no kale around.

Protein is where the wild greens really start to shine, and finally find a metric where they can beat kale, at least for lambsquarter and stinging nettle.

Similarly, for calcium, the wild greens do well compared to typical cultivated greens.  Stinging nettle blows everything else out of the water, but lambsquarter and dandelion are also higher than anything normal gardeners grow intentionally.  Even the lowly mallow is right up there with kale.

Most of the rest of the items that show up on a nutritional label didn't have data across all eleven species, but if you want to take a look at the spreadsheet, you can find it here.  Also, recommended daily values (RDVs) were based on a 2000 calorie diet.  The RDVs we based our calculations on can be found here.

It would be a shame to spend all this time talking about greens and nutrition and leave you hanging with no evidence of them actually prepared!  So we leave you with this: the dandelion-sorrel quiche we made a few weeks ago should be an excellent source of vitamins A and C!

Did we miss your favorite wild or cultivated leafy green?  Let us know in the comments section below!


Now, the sources of the numbers, in case anyone is interested:

Dandelion, lambsquarter, purslane, and all the cultivated greens came from the self.com nutrition facts database.  In the spreadsheet, when figures were available for cooked greens, we used the 'no salt' option.

Sorrel came from the USDA national nutrient database.

Mallow came from this paper and this paper, using the moisture content to back calculate nutrient content in the fresh leaves.  For the second paper, the moisture content was listed as only 2.8%, which is not typical of fresh green biomass!  So the moisture content from the first paper was used in back calculations of the mineral contents.  Also, vitamin A proper was not given, so the total carotenoid content, which provides an upper limit on the possible vitamin A content, was used.  Also, some interconversion between mg and IU was required for vitamins A and E, which we got from here and here.  Finally, note that the two papers analyze different species of mallow (Malva sylvestris in the first and Malva neglecta Wallroth in the second), so there is some uncertainty in the numbers reported here.  This paper also appears to have the data we're after, but only for a price.

Stinging nettle came from this paper, using the spring data because in the fall, there are so many other things to eat.

EDIT 10/19/15: A recent article (covered also here) took a more sophisticated approach, but came up with chard and spinach ranking much higher than kale, which was on par with dandelion greens.  Evidently, they were able to find more complete nutritional data than we did, but they also mention that their ranking system is similarly limited by lack of data on things like phytochemicals.  But we also wanted to mention that watercress, which topped their list, is an excellent wild green, too!  Now if only they had included some of our other favorite wild greens, they would have a perfect article...

Biochar from Butchering Waste

One thing that's been on our minds lately as our chickens rapidly approach the age at which they are released into our small, electrically-cooled pasture is, 'what do we do with the butchering leftovers?'  Growing up, anything leftover from meat-processing or meat-eating operations went out into the open field or out in the woods, just far enough away that the dog wouldn't find it and regurgitate it in the living room.  Sometimes the dog did find it anyway, and if that happened, Dad decreed for the next several batches of meat-related waste that it needed to be taken twice as far and buried at least ten feet deep.  Our impression is that this approach is followed by many other folks, as well, with many variations on the theme.  Cheap and easy?  Definitely.  Sanitary or good for keeping coyotes and raccoons away from your chickens?  Not so much.

On the other hand, if livestock are taken to the local meat market for processing, the guts and feathers and other stuff that doesn't make it to the plate are often hauled away at cost to the butcher, to be rendered into soap, glue, and food for future generations of livestock.  Although that's been changing (especially abroad) thanks to Bovine Spongiform Encephalopathy (BSE, or mad cow disease), dealing with slaughterhouse waste is still a big problem.

Cornell University has a good article discussing different options for taking care of this waste responsibly.  Both economically and ecologically, composting emerges victorious, but there are several considerations that must be taken into account for a favorable outcome.  The first is to have a site available that is well-drained and 200 feet away from any surface water source.  The second is to have lots and lots of high-carbon organic matter (such as wood chips or sawdust) available.  The third is to not have any neighbors that object to the smell if you plan to turn the compost pile in the first 3-6 months.  We're 0 for 3 on that checklist.

In the past, we've had some success with using worm composting to decompose meat-processing waste.  But, like standard composting, precautions must be taken to eliminate odor, including the use of a lot of bedding above the waste.  Also, there's no way our current worm bin size could handle the leftovers from processing seventeen chickens, and we don't know how the vermi's would do with feathers.

Then, earlier this spring, an interesting article, Biochar of Animal Origin, came out in the academic literature about processing butchering waste into biochar for use as a soil amendment.  In particular, the authors focus on the use of animal-bone biochar as a replacement for phosphate rock fertilizers (which are the current phosphate source for most of the industrial agriculture system).  The article is set in the context of averting peak phosphorus (phosphate rock is a rapidly-depleting non-renewable resource), mitigating fertilizer runoff from large-scale fertilizer misapplication, and reducing an industrial waste product (animal bones).  None of those problems may seem particularly pertinent to homesteading-minded folks, but many homesteaders both generate animal-processing waste and make biochar from wood as a soil amendment.  It seems that converting meat-related wastes into a useful product like bio-char would be a permaculture-consistent, hygienic way to process them, even if one did have the space to drag the bones, gristle, and feathers half a mile and bury it ten feet deep like Dad said.

Why would one want to make biochar, other than to get rid of a waste product?  There are a lot of good resources out there on the internets explaining the benefits, but we recommend checking out Anna's lunchtime series on biochar over at the Walden Effect and Shaun's discussion of the matter over at Shaun's Backyard as a good starting point.  Briefly, biochar improves soil nutrient-holding capability (via ion exchange capacity) and texture, and has a porous structure that houses beneficial bacteria.  The bacteria in turn further increase nutrient availability to plants, in part by producing metabolic products that break down the biochar itself (but the carbon base pretty much stays put).  For example, the sciencey paper linked above discusses inoculating biochar with bacteria that produce acidic metabolites, which make the phosphorus in the biochar soluble (and thus available to plants).

Here's a scheme of how animal biochar could fit into a homestead's operation.  Here's a riddle: what becomes naked as it gets dressed?  A chicken!

We haven't tried making biochar yet, but we're working on a biochar retort/oven that we'll hopefully be able to report on in a few weeks.  In the meantime, how do you dispose of your meat-related wastes?  Have you made biochar on a small scale?  Have you made biochar from anything meat-related?  (Other than accidentally burning steaks on the grill.  That doesn't count unless you used then used the char for something useful.)  Let us know in the comments section below!

Honey and Bee Nutrition

It might seem intuitive that feeding bees honey rather than a sugar-syrup substitute would be better for their health.  However, it has become a common practice to feed sugar syrup to bees, and let them get their other required nutrients through pollen.  (That trend is mainly due to a 1978 paper in Apodologie that showed bees could survive as long on corn syrup as on honey, and slightly longer on a syrup of sucrose, or table sugar.  Then, due to the magic of international trade, beekeepers figured out they could sell their honey for much more than an equivalent amount of sugar syrup cost.  The paper can be found here--it's the third in the list, by Barker and Lehner).  So, if honey bees can get most of their nutritional needs from pollen, and only really need honey as a carbohydrate source, what is actually the advantage of feeding honey?  A paper in Proceedings of the National Academy of Sciences from a couple weeks ago has provided some new insight on the topic.

It seems that the honey acts as a sort of extracting medium, which results in bees getting some constituents of pollen and propolis from the honey.  (Propolis is the tree resin-based material bees use to polish honeycomb, seal cracks in the hive, and glue frames to hive boxes.)  These extracted constituents in turn stimulate the bees' immune systems, allowing them to metabolize pesticide residues and resist pathogens.

Some of the compounds extracted into honey from pollen and propolis, except coumaphos (upper left), which is a chemical commonly used to fight varroa mites.  p-coumaric acid (upper right) comes from pollen and was the most universal activator of the bee immune system.  The bottom three come from propolis; pinobanksin (middle bottom) wasn't as helpful as the other two.

As researchers are trying to figure out how the pieces of colony collapse disorder (CCD) fit together, this paper demonstrates how several of the suspected factors might interact to make honeybees susceptible.  (...which is why it was able to be published in such a prestigious journal!)  Beekeepers commonly treat their hives with coumaphos to combat varroa mites, which have become an ubiquitous pest over the last couple decades.  (Coumaphos itself may or may not be a contributing factor to CCD.)  If, at the same time, bees are eating sugar syrup instead of honey, their immune systems aren't sufficiently activated to metabolize the coumaphos (and other pesticides the bees encounter in the field), which ends up stressing the bees in addition to killing the mites.  A corollary is that if the bees' immune systems are not sufficiently activated, they are also less able to fend off other pathogenic bacteria.  If this situation goes on for long enough, the worker bees run out of vacation days, and then sick days.  And once the worker bees run out of sick days, they have no choice but to call in 'dead.'

A varroa destructor mite.  'Varroa destructor' would be a good name for a band (or maybe a professional wrestler), but as a honey bee parasite it should just go extinct.  Someone should discover the anti-varroa equivalent and name it varroa self-destructor.  Photo credit: Wikipedia.

The authors showed that they could get the same immune system stimulation by adding p-coumaric acid to 'bee candy,' a mixture of powdered sugar and sucrose syrup. Then, in an example of how to shoot a good arrow yet miss a target completely, the authors propose that based on this finding, toxicity indices of certain pesticides, which are typically tested on bees eating sugar syrup instead of honey, may need to be re-evaluated. (Because if the bees are eating honey instead of sugar syrup, they can probably handle a higher pesticide load than we're giving them credit for.)  Fortunately, the authors come around to imply that feeding bees sugar syrup laced with p-coumarin is better than unlaced sugar syrup, but is only a good option when real honey isn't available.

Of course, beekeepers can minimize the pesticide load on their bees by invoking natural beekeeping practices.  The Walden Effect has had a few discussions on the topic (e.g., here and here), and there is a growing body of science and experience of how to keep bees without adding synthetic chemicals.

Have you had good luck with keeping your bees healthy?  Have you been able to do it naturally?  Other thoughts on this research paper?  Tell us about it in the comments section below!

Organic Farming, Swedish Style

Every once in a while, a paper gets published in the academic literature that makes readers (or at least, these readers) say, "what a cool set of experiments!"  Such was the case this week with an article published in the journal Acta Agriculturae Scandinavica, Section B - Soil & Plant Science.  A team from the Swedish University of Agricultural Sciences in Uppsala, Sweden took a look at the sustainability of organic agriculture on a small farm for a variety of livestock and fossil fuel demand scenarios.  The authors' test farm was 35 hectares (ha, 86.5 acre), consisting of 8 ha (19.8 acres) arable land, 5.5 ha (13.6 acres) meadow, 3.5 ha (8.5 acres) pasture, and 18 ha (44.5 acres) forest (of which 10.5 ha (25.9 acres) were also pastured).  The main goal was to to find the maximum number of people that could be supported from their organic test farm, and to see if the number changed significantly depending on livestock and fossil fuel scenario (you can see from the abstract in the link above that the livestock make more of a difference than the fossil fuel demand, as long as the fossil fuels are readily available).

Breakdown of how the test farm is distributed.  Areas are proportional but not necessarily representative of how the actual farm looks.  (If anyone wants to send us to Sweden to find out in person, please let us know in the comments section below!)  Arable land is divided into eight one-hectare (2.5 acre) plots.

The authors determined that the farm's demand for "tractive power," or "tasks that are normally done with a tractor," could be optimally met with one diesel-powered tractor and combine, three draft horses, or a combination of one tractor, one combine, and one draft horse.  In the last scenario, the tractor and combine would be used for high power-demand or time-sensitive tasks like plowing, threshing, manure spreading, and grain harvesting, while the horse would be used for most other tasks, like haying, harrowing, sowing, and vegetable harvesting.  Importantly, the combination of horse and diesel power allowed the farm to produce enough fuel on-farm to run the tractor and combine (although the authors don't seem very confident in their ability to produce biodiesel on a small scale, for some reason).  Since one goal was to keep the farm as a self-sufficient unit of production, the diesel-horse combination was especially preferred.

Another important point is that the only fossil fuel demand considered was for "tractive power."  The authors were able to validate this relatively narrow scope because they chose a crop rotation that heavily emphasized ley and green manures, such that additional fertilizers (other than the manure produced by their livestock) were unnecessary.  Specifically, the authors split their 8 ha of arable land into eight 1-ha (2.5 acre) plots, rotated through the following sequence:

1. Alfalfa
2. Rapeseed (similar to canola)
3. Winter wheat undersown with Crimson clover
4. Potatoes and other vegetables
5. Buckwheat
6. Oats, undersown with alfalfa
7. Alfalfa, harvested twice
8. Alfalfa, harvested three times

The yields obtained from these crops (in addition to the forage provided by the pasture and meadow) were used to determine the number of people and animals the farm could support.  The authors chose crops and animals with which they had experience and, thus, accurate baselines for feed consumption and growth rates.  They also made conservative assumptions on the food energy produced, assigning all vegetables to a "lettuce equivalent" and assuming their horses would eat like they were pregnant. (Seriously!)  Specifically, they chose two breeds of Swedish Mountain Cow (one large, one small), North Swedish draft horses, and unspecified breeds of sheep and poultry.  They constructed a model to determine how much livestock could be supported (after feeding the horses), assuming the cows and sheep would eat no grain and the chickens would eat waste grain supplemented with other feed (see below).  Because a cow requires many times more resources than a sheep (about 9.2 times in their system), the farm's production could support in some cases, for example, nineteen cows and seven sheep, but not twenty cows.  Thus, the authors considered a number of livestock scenarios:

1. All large cows, with the remainder of forage going to sheep, plus chickens
2. Same number of small cows, with the remainder of forage going to sheep, plus chickens
3. No cows, all forage going to sheep, plus chickens
4. All small cows, with the remainder of forage going to sheep, plus chickens
5. Roughly equal balance of large cows and sheep, plus chickens
6. Equal number of large and small cows, with the remainder of forage going to sheep, plus chickens

Crop scenario #6 was only considered for the combined horse and diesel powered fossil fuel scenario.  In terms of gross calorific food value (the metric used to determine the number of people the farm could support), crop scenario #1 came out on top for all three fossil fuel scenarios, but the calories came to a larger extent from milk and less from meat and eggs (to the tune of 12-13 liters of milk (over three gallons) per person per week).  Of course, it would be advisable to use some of that milk for butter, yogurt, cheese, etc.  On the other hand, if all of the non-vegetable calories shifted to meat and eggs (scenario #3), the number of people supported decreased by roughly a factor of two.  Of course, there are many other combinations of livestock and crops that could be used to vary milk-egg-meat ratio to produce meat more efficiently while yielding a reasonable amount of milk per person, but this study makes a good starting point.  Notably, in every case, per capita meat consumption well below the current global average was required.

Livestock considered in the various scenarios.  Clockwise from upper left: North Swedish horse, generic sheep, generic chicken, and Swedish Mountain Cows (Photo credit: Wikipedia for horse, sheep, chicken, and cows, respectively).  Generic photos of sheep and chicken used in part to protect their identity from the Swedish Chef.

As with any model, a number of assumptions were made.  Most were based on the conservative side of previous years' data from their research farm or nutrition values from previous studies, but one assumption that wasn't is worth mentioning.  That is, a significant fraction of the poultry feed was assumed to come from slaughter waste of the cows and sheep.  In normal operations, that probably isn't directly a good idea (or even legal).  However, the slaughter waste could be used to cultivate grubs and larvae that would make good chicken feed, so although the assumption is overly simple, it isn't entirely without merit.

One of the main conclusions of the article was that by extrapolating the results of their small organic farm system, it was possible to generate enough calories to feed seven billion people (and in the best cases, nine billion people) in each of their fossil fuel demand scenarios.  Such large extrapolations are always dangerous, but this particular claim that organic agriculture can feed the world has a lot going for it.  First, conservative estimates for yields were used, and the growing season in Uppsala, at nearly 60° N latitude (approximately the division between the northern and southern Canadian provinces), is shorter than in many other inhabited regions.  Second, the system was largely self-contained, not requiring external inputs of fertilizer or, in some cases, even fossil fuels. Although the production of rapeseed esters from the rapeseed oil (that is, biodiesel) would likely require fossil resources (for methanol to make methyl esters) or larger grain yields (to make ethanol for ethyl esters), there is an appreciable cushion of resource availability, at least for the present global population.  (For the authors' preferred scenario--combined horse and diesel power, livestock scenario #6--their farm could support 69 people compared to the 58 people required to extrapolate their results out to global scale.)  Thus, some grain could conceivably be used to produce ethanol and subsequently rapeseed ethyl esters for biodiesel, but the exact balance isn't clear from the article.  In any case, this article constitutes a very promising outlook for the future of organic farming, and the model is a useful starting point for scientists and engineers looking to plan out their homesteads (like we are)!

Have you done any similar calculations for your homestead, or do you know of any tools to help aspiring homesteaders do the same?  Tell us about it in the comments section below!

Biodiversity with Bees

It seems that many times, diversity in ability trumps raw talent, and it turns out that the trend holds in the area of ecosystem services as well.  Basically, the concept of ecosystem services is an attempt to quantify the good things nature provides for us so that they can be taken into account when calculating the true cost of a product or process.  Some examples of ecosystem services include clean air, soil nutrients for food production, and pollination of crops.  Brittain et al. looked at that last one in an article that appears in the most recent issue of the academic journal Proceedings of the Royal Society B: Biological Sciences. (Believe it or not, the Royal Society of London publishes journals with even longer names.)  It turns out that honeybees do a better job of pollinating almonds if other bee species are present (specifically, non-apis bees).  The authors were inspired to try almonds because it also works for sunflowers. 

In short, for crops like (commercial-scale) almonds, where the trees are planted in alternating rows of different varietals, honeybees tend to move more commonly up and down a row than between rows if left to their own devices.  The reasons for this behavior aren’t clear, but one hypothesis is that it happens because the next-nearest (good) flower tends to be in the same row.  In the case of almonds, that’s not good because you need the bees to fly between rows for successful pollination (and fruit set).  What the authors found was that the presence of other types of bees causes honeybees to change their flight patterns such that they fly between rows more often, thereby increasing pollination efficiency.  They suggest that when the non-apis bees are around (and visiting flowers themselves), two things happen because of the increased competition for nectar and pollen.  First, the next-nearest good flower for a honeybee might not be in the same row since a lot of the flowers have already been "emptied" by the non-honeybees.  Second, when the non-honeybees visit a flower, they might leave behind a chemical marker that the honeybees don’t like.  Both might contribute to the honeybees having to look farther for the next-nearest good flower, which is just as likely to be in the next row over as in the same row.  However, the authors aren’t completely sure about the causes.

This little guy, Osmia Lignaria, will tell your honeybees that it's OK to color outside the lines. Photo credit: Wikipedia 

It's important to note, however, the improved pollination would only be expected within certain man-made systems.  That is, if the trees weren’t planted in unnatural rows to begin with, the bees’ movement between trees would have been less biased even without the other bees (but the almonds would be harder to harvest mechanically).  

Isn’t it fascinating that honeybees’ flight pattern can be affected by the geometry of your garden and the presence of other kinds of bees?  Nature never ceases to amaze (me, anyway).  The article also points out another advantage of having other kinds of bees present—some species can forage at lower temperatures than honeybees, which means they can get to work earlier in the day, and also earlier in the season.  That can be especially important if you’re growing early-blooming fruits like apples and cherries in northern climates.

Since honeybees tend to go to the next tree in the line, planting your orchard like this might make your bees dizzy (but probably not).

The article doesn’t say anything about how the changes in movement affect honey production, but if it's pollination you're after, it looks like workplace diversity is important, even if your employees are insects!

Related links: the University of Arkansas has some advice on how to attract certain species of non-honeybees to your garden.