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Nutrient absorption against the direction of water flow

When plants absorb nutrition in a form other than simple ions from the soil solution, we need to reconsider nutrition transport pathways and mechanisms. A first step in connecting the dots is identifying as many dots as we are able. William Albrecht was passionate about the idea that nutrients should be available but not soluble, and he described how plants absorb nutrients into the roots even against the flow of water:

Nutrients are not washed into the plant by the transpiration stream: they enter under their own power1

In that contention that solubilities of high order are required for entrance the plant root, we are apt to believe also that such entrance is connected with the large amount of water moving from the soil into the root, passing through the plant, and evaporating to the atmosphere from the leaf surface. More water is moved through and transpired by the plant according as the evaporation rate from the leaves increases with the rise of the daily temperature, the wind, or air movement over the leaf surface, the lower humidity of the atmosphere, and the larger supply of water in the soil. But because there is a decided flow of water from the soil through the plant for evaporation to the atmosphere, that is not proof that the fertility elements are necessarily moving along that same course because of that current of water as transpiration. Calcium, magnesium, nitrogen, phosphorus, potassium, and all the other essentials are not swept into the plant because they are applied to the soil in water soluble forms of fertilizers and flooded in, as it were.

There are natural facts, some readily demonstrated in the laboratory, which refute such erroneous beliefs that the water solubility within the soil is a requisite for fertilizer availability and flow with the water into the growing crop. As the first fact, plants will grow and their nutrients will move normally from the soil into the roots without the evaporation of water from the leaves. A potted plant, enclosed in a water saturated atmosphere with carbon dioxide under a glass bell jar in the light, will grow normally. This fact tells us that while the transpiration stream is halted because the saturated atmosphere will not take any water of evaporation, the fertility elements are, nevertheless, flowing into the plant from the soil.

In research at the Missouri Station, some soybean plants were grown on soils of such low saturation of the clay by calcium, that the totals of nitrogen, phosphorus and potassium in the total crop of tops and roots were less than those of the planted seed. Such facts tell us that the fertility elements may flow out of the root, or in the reverse direction of the flow of the transpiration stream of water.

That same reverse flow of fertility can be demonstrated under the conditions used for the potted plant within the bell jar, or when there is no flow of transpiration. Such facts inform us that even in the absence of water movement within the plants, the nutrients will move either into, or out of, the plant, entirely independently of either the static or the flowing condition of transpiration water. Forces, other than the water flowing into the plant root, must move the fertility elements serving in connection with plant nutrition.

Still as another situation, the desert plants have shown according to research reports by Dr. Went, now Director of the Missouri Botanical Gardens, that nutrients go into the roots for nourishment of the plants when in the daytime the water is transpired to move from the soil to the atmosphere. Then, also, they go into the roots when at night time the atmospheric moisture of condensation moves from the plant back to the soil sufficiently for plant survival through such diurnal reversals in movement of the limited moisture supply.

These facts deny, categorically, any necessity of water solubility of nutrients for their flow into, or within, the plant for any delivery services of them by the transpiration. They tell us that the fertility, which is feeding – not watering – the crop plants, behaves according to certain laws of physico-chemical relations within the soil and plant, while the water movement behaves according to the meteorological conditions and the climatic situations controlling the conversion of water from the liquid to the gaseous form and vice versa.

Water solubility of plant nutrients in the soil is not the rule of nature for their services to plants. Rather, they are naturally insoluble there, by which condition they remain there against loss through leaching out of the soil. By virtue of that condition they are still there when the growing root comes along. But that fact does not deny their being available through other mechanisms than aqueous solution.

1. Walters, C. The Albrecht Papers, Volume 1–Foundation concepts. Acres USA, Page 219

2020-04-20T15:32:14-05:00March 16th, 2020|Tags: , , |

Organic matter – the “constitution” of the soil

Many reference the Albrecht papers but it seems few have read them, which is distinctly unfortunate, considering he pioneered many of the soil nutrition management guidelines that are still used today, a hundred years later.

When we manage applied fertilizers and amendments, it is very important to consider the nutrient release curves, and time applications so we have the greatest nutrient release at the moment of peak crop demand. Nutrient release curves should dictate whether a product is applied in fall, spring, or after planting.

Of course, when we have abundant organic matter and functional biology delivering all of the crop’s nutrition requirements as the system was designed to function, such close management finesse is no longer required. William Albrecht described this first:

Organic matter – the “constitution” of the soils1

The most neglected and most important chemo-dynamic factor of the soil is the organic matter. Organic matter may be said to be the constitution of the soil. As a definition of the word constitution in that usage, we take its meaning when the doctor consoles the friends of a patient in serious illness by reminding them that the patient has a good constitution. According to its meaning, as used in medical practice, a good constitution is the capacity of the individual to survive in spite of the doctors rather than because of them. The organic matter in the soil has been the capacity for our soils and our crops to survive in spite of the soil doctors, rather than because of them.

Your attention has already been called to the importance of the organic molecule when it is on the clay. There is also the tremendous significance of the organic matter as a season’s release of plant nutrition. This release is timed to increase during the growing season or become larger as the temperature goes higher. The microbial activities follow Vant Hoff’s law and double their rate of decay of the organic residues with every 10° rise in centigrade temperature. Nature has always been fertilizing with the organic matter which is dropped back to the soil from the previous plant generations which have died in place. Organic matter is still the most reliable fertilizer in terms of the nutrient ratios and of the time when maximums must be delivered.

Another aspect of organic matter about which we probably haven’t thought much is the value of some organic compounds in cycle, that is they may be dropped back as crop residues and the next crops roots may be taking them up, using them and dropping them back again. Plants need the various ring compounds in very small amounts to make some of the essential amino acids. They need the phenol ring in phenylalanine, one of the essential amino acids, essential for plant growth as well as for animals and ourselves. They need the indole ring, which is a phenol ring plus a side ring. It is the compound which gives the odor to feces when the digestion acts on the tryptophan of which that ring is a part. Tryptophan is the most commonly deficient amino acid, and is one of marked complexity.

1. Walters, C. The Albrecht Papers, Volume 1–Foundation concepts. Acres USA, (1975). Page 67

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2020-03-16T14:13:13-05:00March 13th, 2020|Tags: , , |
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