Tuesday, December 20, 2005

Mollisols, Agricultural Systems and the Dangers of Static Thinking

One of my favorite blogs is Muck and Mystery, by Gary Jones, a self described bio-geek. In a December 18th post Muck and Mystery includes a map of the global distribution of Mollisols. The map demonstrates that the best agricultural soils in the world are largely in North America and the European Union. We can expect high crop production from these areas and it is self-evident why nations with productive soils can be expected to demand more fertilizer per unit area. The point Muck and Mystery counters is that patterns of crop production and fertilizer use are largely accounted for by patterns of export subsidies.

Hear, hear. Eliminating farm supports in developed countries will not eliminate long term demand for agricultural exports from the US and EU. While there are compelling elements of truth to the notion that agriculture production is a political toy, it becomes a dangerously simplistic construct when extended to justify redistributing agricultural production on a global scale. The planet has limited areas where soils and climate are ideal for crop production. Ignoring the realities of what the land can, and cannot, support is always a terrible mistake. Doing it in the name of economic justice and environmental protection doesn't make it right.

Ignoring what the land compels in the name of other good causes abounds. Whether it is in the name of endangered species protection, wetland protection, smart growth or prime farmland protection, the supply of ironic disconnects far exceeds demand. Thank you Muck and Mystery for holding our collective do-gooder feet to the fire yet again.

Here's a link to a news article shedding some light on the complex subject of export subsidies.
Column: WhereĆ¢€™s that 18 cents for African cotton producers?
Dec 29, 2005 2:56 PM
African farmers should ask their leaders why their prices are 18 cents below world cotton prices

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Anonymous said...

I asked the following of "Back40" and he suggested that I ask you:

With regard to soils, what are the good books on them? Personally, I gained a huge respect for what's underfoot from "Out of the Earth: Civilization and the Life of the Soil", Daniel Hillel, 1992. Any others that are good, eye and mind opening reads?

It seems to me that this whole agriculture / food supply for sustainability thing is going to have to be rethought in light of increasing energy scarcity, water scarcity, population increase, climate change, invasive species (e.g., Bromus tectorum). And soils are the foundation of it all.

Thanks much.

Philip Small said...

Try "Dirt: the Ecstatic Skin of the Earth" by William Bryant Logan, 1995, ISBN 1-57322-004-3.

Sample from the conclusion:

...I ought to start all over again. I ought to write about the man the soil suggests. Hans Jenny is the closest I have found. He was a man of deep integrity. With seven decades of hard-won knowledge, he confessed his ignorance. He insisted on seeing whole, while others made a virtue of seeing in slices. He knew science as a form of prayer.


Soil is only the darkest and coldest of all living things. The most widespread. And the most receptive. Warmed, it blooms. So may I in my darkest moments be attentive to the rays of the sun that finds the seed.

back40 said...

This Wikipedia page on soil seems wrong about a couple of things.

"However if acid is introduced into soil, e.g. by acid rain, hydrogen ions bind in preference to clays, forcing ions out where they can be washed away during rain. Acidity also encourages the weathering of clays, releasing toxic aluminium ions (of which clays are composed) into the solution. To stop this occurring, farmers may apply alkaline materials such as slaked lime."

All the farmers I know of use calcium carbonate rather than calcium hydroxide. Lime grade regulations specify calcium carbonate percentages and mesh sizes.

"In processes such as nitrification and mineralisation, bacteria and other organisms convert unusable forms (such as NH4+) to usable forms (such as NO3-)."

It is my understanding that NH4+ is directly usable by plants, and that cation uptake contributes to soil acidity since to maintain electroneutrality protons are excreted. Legumes are reputed to do this more than other plants and are also reputed to prefer sweeter soil.

Philip Small said...

Wikipedia's soil article needs a lot of attention. Most of the soils-related articles do. In the last month the articles created or updated by User:SoilPhysics are looking stellar and will hopefully help to inspire progress in other soil-related articles.

I can tweek those parts of the soil article that you mention.

Calcium hydroxide can be used to raise soil pH, but calcium carbonate is more common. Calcium Carbonate Equivalent(CCE) is used to compare the lime value between materials.

Ammonium _is_ an available form of nitrogen and especially important to young plants and early in the growing season. Nitrate moves by mass transport and needs transpiration to drive it. Ammonium moves in response to cation gradients. Plants use a lot more nitrate, so sometimes folks lose sight of the fact that NH4+ is a usable form.

The "acid introduced into the soil ..." part could be improved to mention more than just acid rain. Not my area of expertise, but my recollection is that acid rain's impact on soil isn't the hot button it was anticipated to be in the 1970's and 1980's.

Philip Small said...

I have made my changes to the soil article. That soil article still needs much work, although it is much improved from a year ago. I would like to see the article reorganized per Wikipedia guidance. The article on water is an example.

Acid rain (or EPA's preferred term, acid precipitation) is not the issue it once was in the eastern USA and Canada specifically because of continued progress in emmissions controls (See this). It remains a growing problem in parts of Asia and Europe. The causes and effects of acid rain continue to be much debated.