Sorghum Puzzler

Last January I was trying to see if applying fish emulsion could help some Oats that had yellowing leaves and seemed to be struggling.  Now where the sorghum is growing on the same area it is doing much poorer than where nothing was applied. The fish emulsion jug had no label but I later found out that the fish emulsion, 3-1-1, was actually 1% urea and 1% ammonical nitrogen! I really prefer my N to go into the beds in an organic form.  The oats seemed to yield better with the fish emulsion, but now the sorghum which followed is doing poorly compared to the control section.  Could more of the soil OM been somehow oxidized with the N application??  I asked a soil scientist and was told that generally additions of N are always correlated with net increases in OM.  Perhaps then the oats which received the fish emulsion were more vigorous and took more nutrients from the soil than the oats that did not receive fish emulsion.  Or perhaps it is that Sorghum, when faced with a low N situation  grows taller and lankier?  You can see that the taller Sorghum does appear to be a tad N deficient compared to the smaller but lusher green Sorghum in the plot which had earlier received fish emulsion.  Post a comment if you have any ideas what could be going on.

Ancient wisdom on compacting wet soil

The earliest surviving work of Latin prose is Di Agricultural by Cato the Elder.  It's an interesting manual that deals mostly with running a large wine and olive operation.  It is evident though that even highly specialized farms in his time were somewhat self sufficient in that all the workers (usually slaves) and animals were fed from the farm and many of the building materials for baskets and trellises were sourced from on site.  The crops in order of importance are listed as vineyard, irrigated garden, willow planting, olive orchard, meadow, grain land, planting of forest trees for foliage, vineyard on trees and acorn wood.  It was assumed that the olive oil and the wine were to be the principal source of income, everything else was mostly for the maintenance of the farm organism.

I found one passage especially interesting:

Terram cariosam cave ne ares, neve plostrum neve pecus inpellas. Si ita non caveris, quo inpuleris, trienni fructum amittes.

Beware of plowing soil that is wet above and dry below, or of driving a wagon or flock over it.  If you do not beware you will lose three years profit where you have driven over the land.

Here Cato uses the term "cariosum", which the translator Brehaut uses Columella's (another old Roman) description to explain: "Whenever plowing is done, we shall be on our guard to keep the soil from being worked when it is muddy or when it is half wet from light rains, which state of soil farmers call varia or cariosa.  It means when after a long drought a light rain wets the upper part of the soil but does not reach the lower part."

I remember working on a farm where the tractor had been driven a little to early through a wet field and for the rest of the season there were deep tire ruts that dried into rock hard compacted trenches that water could not penetrate.

So what was good for the soil in the second century BC is still good for the soil today.  Though looking at the above picture one might as well phrase it, what was bad for the soil in the second century BC is still bad for the soil today.

I had some corn earlier in this season that had interveinal chlorosis. It seemed like it was on the new leaves so I thought at first could be an Iron or Manganese deficiency.  I checked the soil test and we had the desired levels of Iron and Manganese but our pH was 7.2.  At pH 7.5 Iron and Manganese are hard for plant to access. Someone else looked into this and pointed out that it was probably Sulfur since there was only 5ppm (missed that one!).  I had applied Sulfur in the spring to remedy that but perhaps since it was the granulated form it wasn't very plant available by the time the corn needed it.

So in order to test the hypothesis that it was indeed sulfur that was deficient I applied a foliar solution to the leaves of certain plants.  If sulfur was the deficient nutrient than the interveinal chlorosis would improve after some time.  Unfortunately elemental sulfur is hydrophobic and I didn't have any wettable sulfur so I used Iron sulfate, Zinc sulfate and Manganese sulfate, thinking that if all three worked it would be clear that sulfur was deficient, and if only one resolved the chlorosis then that would be the deficient nutrient.

I would say in general all the corn looks better, but the corn I treated with Iron sulfate didn't show as much dramatic change and I think this might be because it was quite chunky and hard to break up into a powder to get a good solution.  The Manganese sulfate and Zinc sulfate treated corn had a much clearer change.  You can see the two plants where I applied Manganese sulfate in the pictures. Interestingly the old leaves didn't seem to recover that well compared to the new leaves which might point again to the nutrient deficiency being Sulfur since S can be mobile when there is sufficient N.

Corn with Manganese sulfate applied foliarly at 10g/L at Day 1, Day 8 and Day 15

Think of the most iconic breakdown of a state, the most classic revolt of a people against the existing power structure. For many, the French Revolution immediately comes to mind.  Clearly this was a complex event with many factors, but if one were to simplify its causes, wheat is what brought the downfall of the French monarchy.  Wheat harvests had been poor since the 1783 volcanic eruption of Mt. Laki in Iceland and exceedingly harsh winters in 1788 and 1789 had further decimated the wheat crop.  Over the course of 1879, the price of bread rose 67% from 9 sous to 15 sous.  The average French worker was earning 15 to 30 sous a day. In order to afford the two loaves of bread needed to feed a family of four, the worker would then be spending 100-200% of their income on food.


It seems that when more than 40% of income is spent on food social unrest is likely.  Other factors such as a highly extractive government or perceived corruption will help to ensure that this turmoil is aimed at replacing the current state.  So in the case of late 18th century France, with 100-200% of income spent on food and heavy taxes being levied by a corrupt elite to fund a lavish lifestyle, a dramatic revolution seems natural.






Would this revolution have happened had there been a bountiful wheat harvest? Or if French farmers had adopted alternative crops like the potato and food prices remained stable?  I for one do not think so.  It's possible to aruge it was worthwhile in the long run to have these food shortages since it ended feudalism in France, but the point is that agronomy had a direct impact on the direction of the French nation.



Eventually I hope to explore this connection between the stability of nations and their agricultural practices in greater detail.  It is a connection that plays out not only in history but across the headlines of today's news.  Amongst the chaos and violence of a collapsing of nation, it is easy to forget the farmer in his field and the quiet events that preceded these dramatic political convulsions.  But we must fully appreciate how much power the farmer and the soil that he works truly have.  To not apreciate that soil is of the utmost importance to a state is a grave folly.  As Alexandre Dumas (might have) said, "No society is more than three meals away from revolution."