[Digestion] Digestate as fertilizer.

[bingham]

Dear A.D. Karve,

I am not sure I follow your point? 

As part of my degree we studied cotton production in the Mississippi River Delta region of the US,
wheat production in the Mid West US and truck farming in California US.

Many of the really old plantations and farms kept very complete production records. 
Unfortunately they were not very smart farmers.
They planted the same crop for decades with out adding anything to the soil.
There crop yields dropped miserably each year until the river would flood.
After the soil dried out and farming could resume and the crop yields rose back to previous levels.

The Wheat farmers in the Mid West  and the truck farmers  in California had similar problems but there were no floods so NPK was 
added in later years and yields returned.

Old dried Samples of the wheat and produce were found stored that dated back 60 to 100 years.
When the old samples of produce were analyzed and compared to modern samples they had marked differences in the 
amounts of  the trace minerals they contained. 

The old samples had higher levels of almost all trace minerals than there modern counterparts.
Some of the trace minerals were totally absent in the new samples of wheat and vegetables.

Soil samples of the areas where the food samples were taken showed the minerals were depleted from the soil in the root 
zone of the crops. 

In some deeper samples the concentrations of the trace minerals improved but they were unreachable by the plants.

Is your point that the minerals necessary to grow the plants are replenished through natural chemical and biological actions
faster than the plants remove them?

I have a theory that the food we now eat is missing many of the nutrients that were in food eaten by our progenitors.
As a result of the missing nutrients we are now less healthy and prone to exhibit a number of health problems.

If the soil where your "organic manure" is obtained has been depleted of the trace minerals it may aide plant growth but
not the plants nutritional value.

The areas we applied AD byproducts showed improvement to the soil trace minerals in the plants over time.
I did not have the time money or patients to determine why the improvement took place only that it does happened.

It may be the result of a new bio-chemical processes beginning in the soil introduced from the AD or from AD byproducts
themselves.

Brent


  ----- Original Message ----- 
  From: Anand Karve 
  To: For Discussion of Anaerobic Digestion 
  Sent: Wednesday, June 29, 2011 8:13 PM
  Subject: Re: [Digestion] Digestate as fertilizer.


  Dear List,
   The fact that the soil micro-organisms contribute to soil fertility is accepted by all agricultural scientists. Logic tells us that high calorie, non-composted organic matter would serve the microbes best as nutrition. From this point of view, we conducted experiments and found that plain sugar or pulped green leaves were excellent as soil amendments. The rates of application were 25 kg dry matter per ha. Capillary water in the soil always has soil minerals dissolved in it. When one applies a carbon source to the soil, the microbes absorb the necessary soil minerals from the capillary water. There is no need to add minerals through the organic matter. That is why even plain sugar causes soil microbes to increase their numbers. The concentration of minerals in the capillary water is at a dynamic equilibrium. If a mineral molecule is removed from the capillary water by a microbe, it is replaced by a molecule going into solution from the un-dissolved pool of minerals in the soil. We have about 30 km of earth's crust under our feet. New soil is being formed every day. Only 5% of the dry weight of plants is constituted by minerals. Therefore there is an unlimited supply of minerals in the soil. Don't think that it would ever get exhausted by agriculture. And when you apply an organic manure to the soil, don't calculate the NPK in it but count the nutritional calories in it. 
  Yours
  A.D.Karve 
     
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