Sunday, July 5, 2015

A Tale of Two Soils

With the masterful craftsmanship of one Scott Chenoweth, we now have a window into the world beneath our feet. The root window is a thin wooden planter box with one side made up of clear plexiglass.  The planter is divided into two sections so that two different soil treatments can be compared side by side.  Below you can see radish roots growing behind the plexiglass panel.  

The radish in the above picture were grown in very rich soil. Looking to make the most fertile growing medium possible, I created a mixture of compost, worm castings and some soil from my veggie beds.  In the other compartment of the planter I used the poorest bagged soil product I could find.  This "Top Soil Plus" product was just what I was looking for.  Its only two ingredients are sandy loam and forest humus.  I know that the sandy loam almost certainly came from a loam pit, a place where deposits of sandy soil are mined.  This material would be devoid of plant life and extremely low in soil biology.  I suspect the second material, the "forest humus" they are talking about here is some sort of byproduct from the logging industry.  It looked like very fine wood particles, not really humus.  The fact that the bag instructs gardeners to "use where needed to fill in low spots in lawns and gardens," makes it sounds like the company doesn't have many illusions as to the usefulness and fertility of this product.
Radish were planted in the two different soils at exactly the same time.  The same seed was used and the same amount of water applied to each side.  The difference between the radishes in the two soils was striking both above ground and below ground.  To the rigt you can see how few visible roots there are in the poor soil compared to the first photo taken of the rich soil.  These two photos were taken at the same time, each photo is of right below the soil line.

After the radish had set seed the soil was removed from the root window and put onto a board with screws to hold the roots in place.  The soil was then washed away so that only the large roots would remain behind.  One thing that is interesting to note is that the poor top soil product washed away with ease.  The fertile soil high in organic matter on the other hand was an enormous pain to wash away.  There were so many roots that it was a single spongy mass. Water would flow through without taking away much soil.  I had to blast the fertile soil at point blank range with extremely high pressure and even then it took quite a while to get it to wash away.

You can see in the picture below that the radish in the poor soil on the left grew spindly stalks, did not develop large edible portions, and formed very thin roots.  The radish on the right however grew thick edible portions, large networks of roots, and thick stalks with dark green leaves.

This picture below shows how the radish on the right have much darker green leaves than the radish on the left, most probably because of higher levels of plant available nitrogen in the fertile soil on the right.  I don't think the radish on the left in the poor soil would have gotten anywhere near as big as they did had I not given both sides a few doses of animal urine.  It felt like as soon as I applied the diluted urine the radish on the left immediately responded with a growth spurt.  Not very scientific to muddle with the experiment like that but I was curious to see if anything would happen.

Below you can see how the roots grew over time in the two windows.  The fertile soil is first and the poor soil is below.  (Unfortunately the animation starts as soon as the file loads on your browser so they usually aren't synced). You'll probably be able to notice the three week gap when I was slammed at work and neglected to take any pictures. This is when the roots fatten up instantaneously.

Here are some slower versions of the same animation.  Below is the radish in the poor soil.

And here is the radish in the fertile soil.  

One thing the surprised me was just how quickly the tap root on the radish reached the very bottom of the root window.  Within one week of the root starting to noticeably elongate it was already at the bottom of the two foot deep window.  Clearly if given the chance the roots would have gone down much deeper.  In Root Development of Vegetable Crops by Weaver and Bruner, the variety of radish they examined grew roots down to 7 feet deep.

Monday, May 18, 2015

Salting the Earth

Everyone loves a good mystery, so here's a soil whodunnit for you.  I was outside one day when I noticed a large bare spot in the weed lawn.  Only a few dock (Rumex sp) were managing to make a go of it.

You can see that the dock weren't exactly thriving either.

What could have led the once giving soil to forsake the grasses and poison the dock? Excess soil nitrate.
A few months later when the soil
moisture starts to evaproate you
can really see the salts being
left behind

We're all about minimizing water use in my house and a housemate was stepping outside to relieve himself in the night in the exact same spot.  It's right next to the stairs out of the house so it was certainly the most convenient location in the yard.

The urea from the urine was converted to ammonium, then to nitrite and finally to nitrate by soil bacteria. The higher level of salts in the soil (a salt being any ionic compound) due to all the nitrate probably made it pretty hard for the plants to access water. The excess nitrate was also probably toxic for plant growth.  So essentially what we're looking at is urea poisoning the soil biology and plant life in these patches.  

After this year's pathetic winter rains subsided and the soil started to dry out, evaporation and capillary action brought water to the surface of the soil where it evaporated into the air.  The nitrate salts that were dissolved in this water were then left at the soil surface.  You can see where the salt accumulation has left the soil slightly white in these pictures taken a few months later.

This is a visual manifestation of research which show that urea can increase soil acidity and salinity.  Here's one such study from Zhejiang University in China.

Now you might be saying, hold on, there's more to my urine than just urea.  There is indeed, and the wonderful, "Composotion and Concetrative Properties of Human Urine" prepared for NASA, has a great table on page 51 which lists these goodies by concentration.  Urea is the largest constituent of urine, making up 36% on average of its total solutes.  Inorganic salts such as sodium chloride, potassium chloride and potassium sulfate make up 38% altogether.  So the salt accumulation on the surface of this soil can't be blamed solely on urea.

I myself got in on the act of free urea applications on my blueberries - they wouldn't mind a little soil acidification after all.  You can see again the accumulation of salts on the soil surface:

I just have automatic drip set up on these plants so there is never thorough surface irrigation to flush all these salts down through the soil.

While we're on the topic, another soil/urine mystery was recently explained to me.  One spring day, walking by a  cabin where someone had lived for the previous six months, I noticed an isolated patch of thriving milk thistle (Silybum marianum).  This cabin had no toilet and the thisle patch was very close to his door step.  This must have been where he relieved himself each night, but I never understood why the thistles thrived in those conditions.  You could also see the milk thistles growing well on the downslope side of compost piles where the leachate would probably accumulate.  I was able to go to an Elaine Ingham talk a few months ago (mind blowing!) and I had a chance to query her about this.  Apparently thistles do best in soils with 50 ppm nitrate.  So they absolutely love to grow in a cherished pee spot.  Interestingly, milk thistle will also accumulate high levels of nitrate and this can be toxic to livestock.

Here are some pictures from the King County, WA, noxious weed website.  I definitely appreciate the enthusiasm over milk thistle here!

Note that the common theme among these pictures is that they're all on dairies where the cows are probably raising the soil nitrate levels a fair amount.

All this is not to say that urine is bad for the soil.  On the contrary, it is an amazing fertilizer, it just has to be used properly. It's hard to think of another well rounded fertilizer which is as easily accessible. If you are metabolizing protein, good news, there will be lots of urea in your urine along with bonus ionic compounds that will deliver potassium, magnesium, calcium and phosphate to the soil. 

Monday, January 26, 2015

The Global Food Market, Political Instability, and Fertilizers

In a globalized world, we all buy our food off the same market. The supply and demand of our world's food stocks dictate the price of food from New York to Sidi Bouzid.  This can be a good thing.  If crops fail in country A, food can still be purchased on the world market from other countries.  The global food market can also be a bad thing.  If country A depends on imported food and then one day countries B, C, D, and E are willing to pay twice as much for this food, the inhabitants of country A better hope they or their government can pony up the extra cash. The following graph from The Economist illustrates just how much of the world is not able to feed themselves without imports.

Even worse than being unable to afford food imports is when a country is actually producing enough food for its inhabitants but because the global market reaches everywhere, the food is exported to places where people are willing to pay higher prices.

The Irish Famine of 1845-49 is a classic example of this scenario. From Ireland's Great Hunger Museum comes this quote:

"'Although the potato crop failed, the country was still producing and exporting more than enough grain crops to feed the population. But that was a “money crop” and not a “food crop” and could not be interfered with.' Up to 75 percent of Irish soil was devoted to wheat, oats, barley and other crops that were grown for export and shipped abroad while the people starved."

To give you an idea of the level of this injustice, here are a few stats about the amount food leaving Ireland. In the first nine months of 1847, a year when over 400,000 Irish starved, 822,681 gallons of butter were shipped to England.  Even more outrageous is the 1,336,220 gallons of grain derived alcohol that were exported during this same 9 month period.

This phenomenon of food exports from hungry regions of the world happens to this day.  A clip from the great movie, Darwin's Nightmare, illustrates the point quite well:

It's safe to say that the global food market dictates how most people eat.  Sometimes price surges in the market make it exceedingly hard for people to access food.  When people are unable to feed themselves, social unrest often follows.

This graph is from the article Freedom to Riot - On the Evolution of Collective Violence.  It uses data from the book Social Unrest and Popular Protest in England, 1740-1840 by John Archer.  It shows that major outbreaks of social unrest coincide with increases in the price of wheat.  The Y axis should actually read "Average Price of Wheat in Shillings in England and Wales" based on the data. Red lines indicate years with major outbreaks of rioting.  Although these price fluctuations probably had less to do with the global food market of the time period, the graph does show how social unrest and high food prices are related.

Food price spikes and unrest

This next graph is from the now well known paper of the New England Complex Systems Institute, The Food Crises and Political Instability in North Africa and the Middle East.
The dotted red lines indicate the outbreak of food riots and social unrest.  The inset is a graph of the FAO food price index since 1990.  The implication of this graph is that high global food prices helped spark the Arab Spring.  If we recall the first chart from The Economist, the Middle East and Africa are heavily reliant on food imports.  Spikes in global food prices therefore put a lot of strain on this region.  For a more detailed analysis of how declining agricultural production in the midst of the 2011 price increase helped spark the Syrian civil war, check out this older post.

How do fertilizers play into this?  From the graph below it's clear that fertilizer prices spike at the same time as the dramatic increases in the global food prices in 2008 and 2011.   The following graphs were made on using World Bank Commodity Price Data.

The increase in fertilizer prices in 2008 was due to a lot of different factors.

Economic growth in developing countries during this period was accompanied by increased demand for meat and other animal products.  The increased livestock production needed to support this diet requires a lot of grain, and this increase in demand for grains in turn led to more demand for fertilizers.  Subsidized biofuels pushed grain demand even further.  In 2007, 18-20% of all corn grown in the US was used for ethanol.

With the demand for grains and other foods pushing food prices up, farmers in developed countries responded by applying more fertilizer in order to increase yields and profit.  There are diminishing returns on increased fertilizer application, but when corn was at a record high of $6.12 a bushel in 2007, the marginal extra yields from more fertilizer would cover costs and then some.

In the midst of this rise in fertilizer prices, China placed high tariffs on the export of fertilizers.  At the time, China was the world's second largest exporter of phosphorus and the largest exporter of urea.  This was certainly a good move for Chinese farmers as it protected them from the price surge on the global market, but it drove prices for the rest of the world even higher.

Knowing how important easy access to fertilizers is for political stability, numerous countries subsidize fertilizer costs.  This is the case in India, and as detailed in an earlier post, in Malawi.  When fertilizer costs increase, these governments are forced to dig deep into their pockets in order to continue the programs.  The upshot of this is that farmers in these countries do not respond to price increases by using less fertilizer as they still pay the subsidized amount.  Consequently the global market for fertilizers stays high as there is no let up in demand in these countries.

Energy prices also play an enormous role in the fluctuating cost of fertilizers. Synthetic nitrogen production requires 2-3% of the global natural gas supply.  Energy costs were very high in 2007-2008 which of course pushed N fertilizer prices higher.

This is not the only time energy prices have pushed up the price of fertilizers and food.  The graph below charts the food and fertilizer price indices from 1960.  It's possible to see how the 1973 and 1979 oil crises affected both the cost of food and fertilizer.

Eventually, the record breaking fertilizer spike of 2008 subsided.  Farmers were simply unwilling or unable to pay such high prices and fertilizer use decreased.  A similar spike happened again in 2011 along with a more sustained increase in food prices.

There are so many factors at play in the volatile global markets for food and fertilizers.  It's not possible to simply point to rising fertilizer prices as the cause of rising food prices when there are several other important drivers for the supply and demand of global food stocks.  Even with these other factors, there is a definite link between fertilizer prices and food prices. It's very hard to have cheap food when fertilizer is expensive.

Fertilizer price volatility hurts poorer farmers the most. When fertilizer doubles in price a lot of these farmers simply cannot afford to buy fertilizer and consequently produce much less food for themselves and local populations.  When this is combined with an increase in food prices on the global market, these populations have a very hard time accessing food as both domestic and imported sources are expensive.

Because of the dramatic '08 spike in the fertilizer index on the graph above, the food price index spike may not seem that bad. Indeed, for citizens of the US, who pay less on food than anyone else in the world, a mere 6.8% of annual income, the food crises of '08 and '11 were not a big problem.  Say that you lived in Algeria though. You're making the average yearly income of about $4000 USD.  In the fall of 2006 you paid $887 a year on food for your family.  By June of 2008 it would require $1,752 to buy the same food.  Unless you managed to substantially increase your income in that short time period, you're really hurting.  To make the example even clearer, the Algerian situation can be put in terms of a US salary.  If you're making $50,000 annually, in 2006 you would be spending $11,118 on food.  By the food spike of 2011 you're now spending $22,405 on food.  If this happened to consumers in the US one can imagine how angry and unstable the political landscape would become. We have a relatively well functioning democracy which helps to manage the displeasure of our populace. During the food price surge of 2011, there was no political outlet for the enormous frustration that built up under the autocratic regimes of the Middle East.  Within a year the Arab Spring would topple many of these governments:

I think the take away from this is that there is a very real link between political stability and the global food price index for countries that import much of their food. Furthermore, volatility in the fertilizer market contributes to high food prices.  To avoid political problems stemming from dramatic food and fertilizer price increases, domestic self sufficiency in both food production and fertility needs is critical.  The political will to set export tariffs on these products to prevent food/fertility from leaving the country in times of scarcity is another important part of maintaining stability.  Certainly, becoming self-sufficient in food and fertility needs is not something that happens over night, but if the food crises of 2008 and 2011 are a phenomenon that will happen again, countries would do well to start working towards these goals now.

For further reading about the 2008 fertilizer price spike here are a few articles that offer different levels of analysis:

World fertilizer prices drop dramatically after soaring to all-time highs

Factors Contributing to the Recent Increase in U.S. Fertilizer Prices, 2002-08

World fertilizer prices surge 200% in 2007