1.1.6 A discussion of plant nutrition

NOTE : A search engine for this site is available at the bottom.

Click here to return to HIBRIXTM Home Page.

Click here to return to the discussion on maximising crop yield, quality and profit using HIBRIXTM products.

1.1.6 A discussion of plant nutrition

[David Menne – http://www.davidmenne.com/plantsfood]

Traditional plant nutrition has, to date, approached remedial programs through a chronological path of observation, tissue and/or soil analysis, diagnosis, followed by remedy. Such an approach presupposes and accepts certain natural-occurring phenomena as limitations, the realm in which the plant must necessarily function:

1. That the plant must operate within and as such is constrained by an array of existing environmental factors such as climate and weather, the atmospheric concentration of carbon dioxide (0.03%), duration and intensity of light, the seasons, limiting edaphic factors, etc.

2. That the plant must obey certain natural "time" frames of growth and reproduction.

3. That traditional irrigation, fertilization and pest control strategies will express the full potential of a plant's growth and reproduction.

4. That the application of some predetermined, deficient nutrient(s) at a specified time and rate will restore the plant to its optimal condition.

5. That the plant is totally resigned to "autotrophism" and as such must conform to this mode of growth, alone.

More recent practices in the management of soil fertility for biological systems has attracted a number of alternative approaches to understanding soil conditions and plant growth.

The following outlines, in approximate historical sequence, indicate several other concepts for consideration.

Dr Rudolf Steiner

Steiner was the initiator of the concepts that form the basis of biodynamic agriculture - a method designed biologically to activate the life of soil and plants.

Plants are fed naturally through the soil ecosystem and not primarily via soluble salts in the soil water.

Essential features relate to the use of special preparations and other techniques that enhanced soil biological activity, humus formation and soil structural development as the basis for allowing plants to selectively assimilate nutrients as dictated by sun warmth and light

Dr William Albrecht

Albrecht was primarily concerned with a soil fertility approach based on nutrient balance (or ratios) as the foundation for achieving proper fertility relevant to optimal plant growth.

The nutrient balance equations he developed are related to soil total exchange capacity.

Ideal ratios or percentages of cations and anions are defined for different soil types, with the total availability of these nutrients generally increasing (except magnesium and manganese) with their percentage saturation.

The optimal base saturation (cation exchange) ratios are :

60 per cent Ca, 20 per cent Mg on sandy soil and

70 per cent Ca, 10 per cent Mg on heavy soil

3-5 per cent K

10-15 per cent H and

2-4 per cent for other bases.

The Albrecht system nutrient dose recommendations are actually based on lbs nutrient/acre. To get ppm, divide lbs/acre by (inches of root zone soil/3). For example :


9" soil (*)

300 lbs/acre of P2O5 100 ppm
600-900 lbs/acre of SO4 200-300 ppm
80 lbs/acre of Mn 27 ppm
4 lbs/acre of Cu 3 ppm
12-14 lbs/acre of Zn 4-4.7 ppm
200-300 lbs/acre of Fe 67-100 ppm

(*)Soil depth is established by inserting a soil compaction tester; and measuring at what depth the gauge reaches 300 psi, beyond which roots cannot penetrate.

Dr Carey Reams & Dr Phil Callaghan

Their work is based on the concept of defining the potential for plant growth and fertiliser performance in terms of energy release and energy exchange.

The contention is that fertilisers in themselves did not stimulate plant growth. It is the energy released (electromagnetic influence or paramagnetic energy fields) from these fertilisers that enhanced production.

A distinction is made between fertilisers (nutrients) that produce growth energy, i.e. calcium, potash, chlorine, and nitrate nitrogen, to those that produce reproductive (fruiting energy), i.e. ammonium nitrogen, sulphate sulfur, manganese and phosphate.

The approach also involves a proposition that the nutrient energy potential was dependent on microbial activity, and that energy availability is determined by nutrient balance. The approach also argues that phosphate is the primary catalyst in photosynthesis and subsequent plant sugar production.

Increasing sap sugar levels (brix) is believed to reduce susceptibility to pest and disease attack and that plant sap sugar levels is directly related to plant pest and disease susceptibility.

Various approaches and analyses relating soil conditions and plant growth continue to be developed and a vast array of alternative input products are available. Scientific verification of many of these contentions and products has yet to be established. As a consequence the decision to adopt particular approaches tends to rely on anecdotal information and experience rather than rigorous scientific testing and understanding.

Approximate Preferred Reams soil balance :

ppm ex Morgan Extract(**) :

Compound :

ppm

Ca

3000

Mg

250

P2O5

400

K2O

200

N as NH3

50

N as NO3

50

SO4

140

Na

40

Mn

30

Fe

40

Cu

15

B

4

Cl

3

Co

4

Conductivity

350 microSiemens

pH

6.5

P2O5/K2O

2 [crop] to 4 [grass]

(**)1.25 M ammonium acetate at pH 4.8

Thomas Yamashita

Yamashita’s theory of "compensatory balanced nutrition" [CBN] is based on a rigorous attempt to define growth rate, in particular the energy required and available for this to occur; and the associated demands for nutrients, nutrition factors and other adjuvants.

Implementation of the CBN Theory requires the following steps:

1. One needs to calculate the energy units within plant tissues of an hypothetical, superior plant; (e.g., fruits, nuts, supportive tissues).

2. The contribution of the primary macronutrient, nitrogen (N), is estimated from protein constituents (calculated in No. 1 above).

3. Quantities of N obtained in No. 2 above are assigned energy of assimilation value.

4. The sums of energy requirements calculated in 1 and 3 above, then, represent the theoretical energy demand for the hypothetical superior plant one hopes to achieve.

5. The solar energy harvesting capacity of the untreated plant is estimated.

6. The Kcal value obtained in No. 5 represents the potential harvestable solar energy, which is then corrected for the actual photosynthetic efficiency of plants which runs

between 0.5%-3.5% depending on species, growth phase etc.

7. The energy demand (No. 4) is subtracted from the actual harvestable solar energy (No. 6). If the value is negative, this represents a deficit in energy which must be compensated to achieve the hypothetical superior plant.

8. In most cases a deficiency of energy units will have to be compensated with formulations aimed to provide a broad spectrum of materials including :

1. Assimilable carbon skeleton/energy components; which are the key to delaying senescence; increasing the number of plastids per cell (including chloroplasts and mitochondria); increasing thylakoid formation; increasing thylakoid polypeptides; increasing cellulose synthesis; increasing the rate and amount of organic acids secreted by roots, thus improving the ability to extract mineral elements from the soil; increasing the rate of differentiation of cells; stimulating cyclic AMP formation, thus regulating intracellular

metabolism leading to increased enzyme activity and overall metabolic efficiency.

2. Macronutrient component.

3. Micronutrient component.

4. Vitamin/cofactor component.

5. Enhancement agent components such as Complexing Agents; Growth Regulators;

Gum Components; Microbialstats and Buffers.

Yamshita points out that it is known that microscopic passage canals, the ectoteichodes, provide communication channels with the outside environment and thus are avenues for absorption of compounds and elements. With the appropriate use of surfactants it may be possible to get materials through the stomata as well.

Furthermore, actively transported compounds, which thus require ATP, may gain additional help by the increased oxygen absorption induced by both "salt respiration" and added metabolizable energy units.

General discussion :

For horticulture, one would be aiming to develop a high Cation Exchange Capacity [CEC] and carbon soil; with specific nutrients in the preferred ranges indicated above.

CEC; Ca/Mg/Na

Probably the most challenging aspect could be the generation of sufficient clays– formed by the breakdown of various rock minerals - to achieve high CEC.

Carbon [humus], of course, could serve as a stand-in for the CEC which could be contributed more permanently by clays; and Zeolite might serve as a shorter term solution – less fugitive than organic material [carbon] which can become depleted if not managed properly.

CEC represents how much of key cations - in particular necessary Ca, Mg and Na - are held in the soil as a source of nutrients for the plants, without being leached out.

They need to be balanced, as all nutrients need to be – the Reams recommendations in a Morgan Extract as set out above being a general guide – albeit at the upper end of the fertility scale : 3000 ppm Ca, 250 ppm Mg, 40 ppm Na.

Note though that such balance in soil nutrients is determined not only by the minimum quantities(*) but in maxima(**) which may be established as ratios under certain conditions.

(*) eg as based von Liebigs Law of limiting nutrients which states that plant growth is limited by a single resource at any one time; only after that resource is increased to the point of sufficiency can another resource enhance plant growth.

(**)Thus Andre Voison’s Law of the Maximum is aimed to describe how an excess of one nutrient ties up others.

A most exemplary phenomenon is the 1.5% increase in exchangeable hydrogen for each 0.1 pH unit below 7 – which displaces other cations.

Some other Voison phenomena are summarised below :

Excess

Ties up

K

B

P

Zn [Cu?] Mn

N

Cu [Zn]

Ca

All

H+

Exchangeable cations

Carbon

No specific limits are noted in the Reams balanced soil recommendations.

However a soil organic content [carbon] over over 1% is deemed useable in sandy soil [3% in clay soil].

However, under 2.5% carbon is prone to lose nutrients by leaching; inter alia because such soil holds under 50 mm precipitation(*); and also because it has a strong Cation Exchange Capacity : humus has about 3x greater capacity than an equal volume of clay.

(*)Soil water holding capacity equals about 11(% Carbon)1.6 mm precipitation.

A practical lower limit of 2.5% carbon – in fact preferably double this, is generally advised, as less than 2.5% carbon keeps microbes – a major soil fertility factor, see Figure 1, on a starvation diet.

 

Figure 1 : Correlation between crop yields and occurrence of soil bacteria. Waksman, Selman. 1952. Soil Microbiology. John Wiley & Sons, New York

Other benefits of raised carbon levels is that humus introduces a buffer capacity : high phytotoxic concentrations of for example of copper or zinc are bound and released at practical use levels by humus; and nitrogen doses that would cripple the microbial populations in soils more poor in humus [carbon], are held back by the humus for slow release.

Finally : Apart from contributing tilth which reduces compaction [see note on humus loss, next item], every 1% of carbon will deliver around 32 kg Nitrogen – given the other nutrients [eg Ca/Mg] are balanced.

Loss of humus [carbon]

Humus is unfortunately easily lost following compaction, eg through working heavy soil when wet.

One of the disadvantages of megafarms, is that some soil needs on occasion to be worked wet to get the entire crop in timeously.

Working wet soils annihilates air and water spaces. Removal of the air space destroys the environment that beneficial microbes need : aerobes cannot break down residues properly.

Most stover has merely 1 part nitrogen to over 60 parts carbon, which must be built up to 1 part nitrogen per 10.4 parts carbon to build humus.

A lack of nitrogen by nitrifying bacteria in anaerobic soil leads to the loss of 60-10.4 = 49.6 parts carbon as methane.

The quality [and over 80%] of the potential humus just evaporates.

Practical data indicates that one season working wet soil can set back 3 to 4 years build up of humus from previous years.

Nitrogen

Reams recommendations in a Morgan Extract are around 50 ppm each of NH3 nitrogen and NO3 nitrogen - albeit at the upper end of the fertility scale.

Most crops are relatively large consumers of nitrogen; much of which can be supplied by recycling and nitrogen-fixing microbes – and particularly by nodule-innoculated legumes.

Supplementing the nitrogen as required for peaking crop production is an art; inter alia because feeding too much [around 100 kg/Ha] switches off the nitrogen-fixing microbes : they go into hibernation believing they have done their job.

The art of such nitrogen supplementation is a bit complex and most of it beyond the intended scope of this General discussion; but will be incorporated in later updates.

However, inclusion of Thomas Yamashita’s discussion – based on his energetic Compensatory Balanced Nutrition [CBN] Theory - on the balancing of trivalent and pentavalent nitrogen provide some insights into the underlying phyto-phenomana :

Both trivalent nitrogen, e.g. in the form of ammonia or a compound which is readily convertible to ammonia such as urea, and pentavalent nitrogen such as a nitrate are plant nutrients and sources of the macronutrient N.

Trivalent nitrogen in the form of ammonia or urea requires much less energy for assimilation than does pentavalent nitrogen in the form of nitrate.

The reduction of nitrate to ammonia using NADH as an energy source requires 198 Kcal per gram mole and further steps in assimilation require approximately 51 Kcal, making a total of about 249 Kcal.

If the nitrogen is added in the form of ammonia or urea, an energy saving of about 198 Kcal would be accomplished.

While the use of trivalent nitrogen may appear remedial in conserving the plant's energy load, the application of purely reduced N forms may be harmful.

It has been shown that the rapid assimilation of ammonia can place a sudden drain of both carbon skeletons and energy upon the plant.

In the presence of abundant carbohydrate reserves, this may not pose a problem.

However, the rapidity with which assimilation can occur oftentimes depletes existing reserves to dangerously low levels.

Firstly. this latter physiological state of low carbohydrate:N (CHO:N) ratio may then promote highly vegetative and little reproductive growth.

Secondly, the ammonium ion can inhibit photosynthetic electron transport systems.

In this latter case, then, sole reliance upon ammonia forms of N can be somewhat toxic to the plant.

Urea forms can be quickly converted via urease to ammonia and thus are subject to similar considerations.

Additionally, heavy concentrations of urea may act to denature proteins by breaking sulfhydryl bonds and disrupting the tertiary structure of the molecule.

If the protein is an enzyme, the denaturation process may potentially disrupt an entire cascade of biochemical reactions.

It is important, then, that a balance between the pentavalent and trivalent forms of nitrogen is maintained during applications to plants.

The soil environment offers a degree of buffering due to microbial conversions of ammonia to nitrate forms, but the tri and pentavalent balance is especially important during foliar applications.

These ratios preferably range from 10 mols of trivalent N to 90 sole of pentavalent N to 90 solo of trivalent N to 10 close of pentavalent N and most preferably should stay close to a 50:50 ratio.

The importance of balanced nitrogen is heightened even more during applications of anions such as phosphates or

sulfates, for example, as these require additional energy outlays for absorption.

When the nutrients are applied during periods of physiological stress and low metabolic efficiency, then, the plant must literally suffer additional stress.

All such factors further emphasize the importance of a carbon skeleton/energy component applied in conjunction as a compensatory factor, providing both energy and carbon skeletons during a critical, physiological, ebb in the life of the plant.

An example of a current used technique to enhance growth and/or crop production of plants and of its limitations is as follows:

Nitrogen added as a fertilizer or plant nutrient may be in the form of pentavalent (oxidized) nitrogen such as a nitrate or in the trivalent (reduced) form such as ammonia or urea.

Assuming that the nitrogen applied to a plant is converted to a protein in which the nitrogen is trivalent, if the form of

the nitrogen added is a nitrate it must be converted to the trivalent form which requires a considerable expenditure of energy over and above what is required if the nitrogen is applied in the form of ammonia or urea.

The energy required must come from tissues of the plant directly or through photosynthesis.

This would indicate that the application of nitrogen as ammonia or urea would place less demand upon the plant.

However the application of nitrogen wholly as ammonia or urea has or may have disadvantages such as:

1. A sudden drain of both carbon skeletons and energy of the plant.

2. The sudden drain of both plant carbon skeletons and energy, creates a low carbohydrate:nitrogen ratio, which promotes vegetative growth, but marginal reproductive growth.

3. Inhibition of photosynthetic electron transport by the ammonium ion.

4. Urea-mediated denaturation of proteins through disruption of sulfhydryl bonds.

In practice, the following observations [http://www.tristatebiosystems.com] are usefully considered :

1. Never apply more than 70 kg of actual N/Ha in one application

2. Anchor nitrogen with a carbon source and/or a sulfate whenever possible

3. Apply no more than 40-50% of the total program nitrogen pre-plant

4. Never!!!! reduce the amount of nitrogen used by more than 25% from the previous year. Always consider total N including manure, green manure crops and biologicals when determining last years nitrogen total

5. Anhydrous should be avoided or used at a rate less than 80 kg actual N/Ha per year. While anhydrous gives good yield response and is cheap, it solubilizes the organic factor in the soil causing it to leach out of the topsoil.

This results in reduction in pore space, reduction of nutrient and water holding capacity, and causes the soil to become hard.

6. Aqua Ammonia, even if it contains a carbon source, is only "somewhat" less damaging to the soil organic matter. Aqua Ammonia does not mix well with the sulfate form of other nutrients.

For example, it lends to precipitate potassium sulfate out of solution

7. It is impossible to successfully lower nitrogen applications on soils with low calcium or high magnesium contents

Phosphorous

Phosphorous is the second of the main NPK macronutrient trio.

Reams recommendations in a Morgan Extract as set out above are 175 ppm P [400 ppm P2O5] for crops – and double that for the healthiest pastures.

The major problem is generally poor availability because it has been fixed, inter alia by high Ca and Fe levels – and in rare cases, phosphorous can even be tied up by Zn.

Microbial processes which release phosphorous are of great importance; as is management of precipitation chemistry

Potassium

Potassium is the third of the main NPK macronutrient trio.

Reams recommendations in a Morgan Extract as set out above are 166 ppm K [200 ppm K2O] – albeit at the upper end of the fertility scale.

The major problem is generally insufficient levels because it is highly soluble and lost by leaching.

The benefits of continuous release by microbial breakdown of rock minerals; and retention until required for use by the Cation Exchange Capacity of clay minerals and/or humus [carbon] is obvious.

Sulphur

Reams recommendations in a Morgan Extract as set out above are 47 ppm S [140 ppm SO4] – albeit at the upper end of the fertility scale.

Sodium

Sodium [and chloride] are factors often viewed [incorrectly] as generally deleterious. However small amounts appear to play useful roles if the phyto-supression of plant diseases, and the Reams recommendations in a Morgan Extract as set out above are 40 ppm Na.

Iron

Reams recommendations in a Morgan Extract as set out above are 40 ppm Fe.

Manganese

Reams recommendations in a Morgan Extract as set out above are 30 ppm Mn.

Copper

Reams recommendations in a Morgan Extract as set out above are 15 ppm Cu.

Boron

Reams recommendations in a Morgan Extract as set out above are 4 ppm B.

Cobalt

Reams recommendations in a Morgan Extract as set out above are 4 ppm Co.

Other :

Values of Reams recommendations in a Morgan Extract for Zinc and Molybdenum are still being sought.

Chloride

Chloride [and sodium] are factors often viewed [incorrectly] as generally deleterious. However small amounts appear to play useful roles if the phyto-supression of plant diseases, and the Reams recommendations in a Morgan Extract as set out above are at least 3 ppm Cl.

Summary

Considering the above, there are thus soil needs for [volcanic : basaltic and/or granitic] rock dust; carbon [compost and/or peat or low rank leonardite/brown coal]; possibly supplemented by Zeolite.

Microbes –either endogenous to the existing soil or added for the purpose, and HIBRIXTM to feed them, ensure the accelerated conversion of the rock minerals to clays; which furthermore ensure slow release of nutrients in the rock dust.

Concomitant with the building of a correct soil structure, fertilizers [and composts] are added to achieve the soil nutrient balance ranges set out above.

Recommendations based on the guidelines set out by the generations of Greats in the rebuilding of soils : Albrecht, Reams and Kinsey; are included above as a guide to the major nutrient balances one needs.

The use of HIBRIXTM ensures that the microbial population is highly active and inter alia producing [zymogenically derived] substances essential to good plant growth.

Furthermore the HIBRIXTM supplies many of these substances – produced from plant extracts and/or using plant chemistry as well as through addition of a full and balanced range of trace elements and ultra-trace elements – directly (at least in prophylactic quantities).

   Search this site or the web        powered by FreeFind
 
 
In the FreeFind search you can use :

1.+ and - qualifier : Examples : +always -never
If you prepend a word with + that word is required to be on the page.
If you prepend a word with - that word is required to not be on the page.

2.* wildcard : Examples : *owned or gift*
If a query word starts or ends with a * all words on a page which end or start the same way
as that query word will match.

3.? wildcard : Examples : a?sorb, a?sor?tion or gift?
If a query word contains a ? any character will match that position.

All of these techniques can be combined: +alway* -ne??r*

HIBRIXTM Microbe and Plant Tonics : Nature's Chemistry

Dedicated to developing HIBRIXTM Tonics and Advising Sustainable Production Methods
focussing on Soil Quality and Ecology for
optimising plant health, produce quality and animal and human nutrition.

May this product bless you
with Improved Yields
and improved Crop Quality.


Frank Pownall : Sales & Marketing
FAX : +61 8 6380 2531 TEL : +61 8 6380 1499 MOB : +61 418 364 880 EMAIL : fpownall@iinet.net.au

David Martin Menne : Technical Support
FAX : +61 8 9389 5647 TEL : +61 8 9389 5648 MOB : +61 418 953 691 EMAIL : menne@iinet.net.au

POSTAL ADDRESS :
P O Box 629 Nedlands, Perth, Western Australia 6909