NRM North Soil Conditioning Trial

NRM North
Soil Conditioning Trial

Project Staff:
TP Jones & Co Agronomy Services
Corey Hogarth
Iain Bruce
Lachlan McFadzean
Oliver Scott-Young

Project Leader:
Dr. Corey R. Hogarth
Mobile: 0418 6111 91
Fax: 03 63 442 706
Email: [email protected]

Acknowledgements:
Charles and Janet Wallace – Woodbourn, Cressy
Lauchie Cole – Woodbourn, Cressy
Tasmanian Alkaloids
Chris Cheek – TA Field Operations
Liz Preece – TA R&D

1

Introduction

Since the adoption of centre pivot irrigation, cropping intensity in the Cressy/Longford area of the
Northern Midlands has tended to increase significantly. In the past, paddocks were cropped for 1-2
years then laid down to permanent pasture for 5-6 years before re-cropping. Recently this has
evolved to cropping for 3-4 years followed by 1 year of grass seed production and another year of
grazing (in effect a 2 year pasture phase).

In addition to increased cropping frequency soil cultivation has also increased as paddocks are
prepared for raised beds and crops that require fine seed beds such as poppies and onions. Potato
crops are also grown in the area and the detrimental effect that this crop potentially has on soil
structure is well known.

It is common to find Soil Organic Carbon levels of 2% or lower in cropping paddocks within the area;
this is considered sub-optimal organic carbon levels for plant growth.

The decline in Soil Organic Carbon has the potential to have a significant negative impact on
productivity as it is associated with so many processes with-in the soil profile.

This study was undertaken in order to investigate the contribution that soil amendments high in
organic matter and bio-stimulates can have on Soil Organic Carbon levels and crop performance.

Methods

The trial was conducted on “Woodbourn”, owned by Charles and Janet Wallace, which is located just
south of Cressy in Northern Tasmania.

The treatments were applied to two pivot circles, (see Treatment Map) the West Woodbourn Circle,
in which poppies on raised beds were grown, and the East Woodbourn Circle in which a seed crop of
“Kano” Italian ryegrass was grown.

Treatments

Poppy Seed Waste (PSW) is a by-product produced by the Macquarie Oil Company from the process
of extracting oil from poppy seed, which is then used in the manufacture of bio-diesel. As well as
containing a high level of organic matter, it also contains a range of plant nutrients (Appendix A).

TM21 Agricultural Soil Rejuvenator is a bio-stimulate produced by BEST Australia that claims to
increase the populations of beneficial micro-organisms in the soil, resulting in a range of benefits for
both soil and plant health (Appendix B).

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Half of each pivot circle had the PSW applied at four applications rates, and TM21 was applied to the
other half, again at four application rates.

Table 1. PSW and TM21 Application Rates TM 21 @ 0 mL/ha
1 PSW @ 0 t/ha TM 21 @ 125 mL/ha
2 PSW @ 2.5 t/ha TM 21 @ 250 mL/ha
3 PSW @ 5 t/ha TM 21 @ 500 mL/ha
4 PSW @ 10 t/ha

The PSW was applied with a commercial fertiliser spreader truck after the last cultivation prior to
bed-forming in West Woodbourn poppies, and prior the final cultivation in the East Woodbourn
grass seed crop.

The TM21 was applied in one application in a tank mix with Glyphosate prior to sowing for the 125
and 250 mL/ha treatments. The 500 mL/ha rate was achieved with two applications, 250 mL/ha was
applied with the Glyphosate application, then another 250 mL/ha was applied with the first post-
emergent herbicide for both the poppies and the grass seed.

Results

As the treatments in this trial were not replicated the results obtained are not statistically valid and
should not be used as the basis for any recommendations in crop management. The main objective
was to determine if there is any evidence to justify further investigation into the treatments.

Grass Seed Crop Yields

There were no definite trends apparent from the application of TM21, at all application rates the
yields were lower than the control. The application of PSW did result in higher yields compared with
TM21 treatment overall, when the treatments rates were averaged the PSW yielded 974 kg/ha
more, or an increase of 95%.

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Graph 1: Grass seed yields for both TM 21 and PSW treatments, dotted lines indicate treatment
averages.

The application of 2.5 t/ha of PSW increased the grass seed yield compared with the control,
thereafter increasing the rate further resulted in yields declining. Potentially this may have been
caused by the increased nitrogen levels applied resulting in higher levels of vegetative growth at the
expense of seed production. This indicates the importance of getting the soil and plant nutrient
balance right to take advantage of the higher levels of available nitrogen.

Similar results have been reported in wheat, in which yields in crops which had trace nutrient
deficiencies reduced as the rate of nitrogen applied increased (Yarra Australia Pty Ltd).

The sap analysis test results do indicate an increase in nitrate levels with the application of PSW at
10 t/ha, this was the only treatment in which the sap nitrate status was close to the desirable level
of 400 ppm. In all treatments a significant number of nutrients were recorded as being below
desirable levels. It may be possible to increase yields by addressing these deficiencies by the
strategic application of these nutrients during crop growth.

The sap analysis tests indicate that either not enough nitrogen based fertiliser is being applied to
achieve maximum yield, or the low levels of other macro and micro nutrients are restricting the
uptake and metabolism of nitrogen.

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Poppy Crop Yields
Overall the yields from the TM21 treatments were higher than the PSW treatments by 231 kg/ha or
9.5%, which is not a strong trend in comparison with the Grass Seed Yields, and may have been the
result of differences in cropping history.

Graph 2: Poppy yields for both TM 21 and PSW treatments, dotted lines indicate treatment
averages.

There did appear to be an upward trend in yield with increasing application rates in both the TM21
and PSW treatments, this trend was more consistent however in the PSW treatments where yields
increased steadily with higher rates of PSW applied. Both the highest yields from the TM21 and PSW
treatments were 143% higher than recorded in their respective control plots.
With the application of TM21 at 125 mL/ha there was an increase in yield compared with the
control, at 250 mL/ha the yield remained around the same and then increased again with the
application of 500 mL/ha to record the highest yield of all treatments.
There did not appear to be any trends associated with the application of TM21 in regards to Alkaloid
% with no increase or decrease of Alkaloid produced with higher application rates.
The application of PSW did increase the Alkaloid % compared with the control at 2.5 t/ha and
peaked at 5 t/ha, at the 10 t/ha rate the Alkaloid % began to decrease.

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Graph 3: Poppy Alkaloid percentages for both TM 21 and PSW treatments, dotted lines
indicate treatment averages.

It would appear that the area of the paddock to which the TM 21 treatments were applied had a
better overall yield and Alkaloid % which may have been due to the different cropping history of this
area. The Woodbourn West – South section had been used for perennial ryegrass seed production
in 2009/10, and then maintained as a grass based pasture until the raised beds were put into place
and the poppies planted in 2011/12.
The Woodbourn West – Nth had grown poppies in 2008/09, followed by Italian ryegrass seed
production and then processing beans in 2010/11. This more intensive cropping history was
reflected in lower Total and Active Carbon levels and may have influenced the lower control yields
for this area of the paddock.

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Economic Analysis

Grass Seed

The most profitable treatment was the application of PSW at 2.5 t/ha, higher rates of application
increased the variable costs and reduced yields to the extent that the 10t/ha application rate had a
lower return per hectare than the control.

All the TM21 applications rates results in lower returns than the control.

Table 1: Grass seed ROI analysis for TM21 and PSW

TM21 Grass Seed Yield kg/ha % of Control $/kg Grass Seed
Treatments 1,394 100% $1.85
0 mL/ha 949 68%
125 mL/ha 594 43%
250 mL/ha 1,143 82%
500 mL/ha

Treatments ROI Analysis Product $/L Application $/ha $/ha Crop $/ha Extra Return $/ha
0 mL/ha $2,579
125 mL/ha $50.00 $30.00 $36.25 $1,756 -$859.50
250 mL/ha $50.00 $30.00 $42.50 $1,099 -$1,522.50
500 mL/ha $50.00 $30.00 $55.00 $2,115 -$519.35

PSW Grass Seed Yield kg/ha % of Control $/kg Grass Seed
Treatments 1,897 100% $1.85
0 t/ha 2,251 119%
2.5 t/ha 2,069 109%
5 t/ha 1,760 93%
10 t/ha
Product $/tonne Application $/tonne $/ha Crop $/ha Extra Return $/ha
Treatments ROI Analysis $3,509
0 t/ha $50.00 $50.00 $250.00 $4,164 $1,335.45
2.5 t/ha $50.00 $50.00 $500.00 $3,828 $748.75
5 t/ha $50.00 $50.00 $1,000.00 $3,256 -$322.90
10 t/ha

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Poppies

The highest return from the TM21 application of 500 mL/ha was $8007/ha which was a 149%, or
$2,573/ha, higher return in terms of $/ha than the control and was an excellent result. The cost of
the TM21 and application is also relatively low which increased the profitability of this treatment.

After taking into account the cost of the PSW and application costs, the most profitable rate was the
5t/ha application rate. The higher yield obtained by the 10 t/ha rate was not enough to compensate
for the smaller increase in Alkaloid % and higher application costs.

Table 2: Poppy ROI analysis for TM21 and PSW

TM21 Poppies Yield kg/ha Yield % of Control Alkaloid % Alkaloid % of Control $/t
Treatments 2,130 100% 3.42 100% $2,525
0 mL/ha 2,778 130% 3.53 103% $2,620
125 mL/ha 2,685 126% 3.45 101% $2,525
250 mL/ha 3,056 143% 3.54 103% $2,620
500 mL/ha

Treatments ROI Analysis Product $/L Application $/ha $/ha Crop $/ha Extra Return $/ha % of Control
0 mL/ha $5,378 100%
125 mL/ha $50.00 $30.00 $36.25 $7,278 $1,863.86 135%
250 mL/ha $50.00 $30.00 $42.50 $6,780 $1,358.88 126%
500 mL/ha $50.00 $30.00 $55.00 $8,007 $2,573.47 149%

PSW Poppies Yield kg/ha Yield % of Control Alkaloid % Alkaloid % of Control $/t
Treatments 1,944 100% 3.18 100% $2,240
0 t/ha 2,407 124% 3.51 111% $2,620
2.5 t/ha 2,593 133% 3.74 118% $2,810
5 t/ha 2,778 143% 3.48 109% $2,620
10 t/ha

Treatments ROI Analysis Product $/t Application $/ha $/ha Crop $/ha Extra Return $/ha 100%
0 t/ha $4,355 145%
2.5 t/ha $50.00 $50.00 $250.00 $6,306 $678.09 167%
5 t/ha $50.00 $50.00 $500.00 $7,286 $1,408.08 167%
10 t/ha $50.00 $50.00 $1,000.00 $7,278 $900.11

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Crop Establishment

There were no trends evident in the number of plants established either with-in or between the
treatments.
Initial crop establishment of the poppies was poor in both treatment areas, and the entire crop was
re-sown.

Graph 4: Poppy plant numbers per square meter for all treatments.

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Soil Test Results

Active and Total Carbon

Graph 5 (Left): Active Soil Carbon for all poppy treatments.
Graph 6 (Right): Active Soil Carbon for all grass Seed treatments.

All treatment area had similar levels of Active and Total Carbon initially. No treatment resulted in
higher levels of Active Carbon, and a significant reduction in Active Carbon was recorded in all
treatments, most likely due to the intense cultivation associated with this cropping system. As
Active Carbon is the most biologically active form it is most likely to be affected by cultivation.
As expected Total Carbon levels remained much more stable across all treatments and time of
sampling. The addition of PSW at 10 t/ha appeared to have no effect in increasing Total Carbon
levels. From these results it would appear that the greatest impact that farmers can have on
maintaining soil carbon levels is to minimise cultivation rather than try to add carbon into the system
from other sources.
As previously discussed the levels of Total Carbon on the TM21 area of the poppy trial most likely
reflect the longer grass phase before the poppy crop was grown. The Total Carbon level may be a
good indicator of the yield potential of poppy crops based on these observations, and confirms the
recommendation of Tasmanian Alkaloid field officers that good poppy crops are often grown
following several years of productive pasture.

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Graph 7 (Left): Total Soil Carbon levels for all poppy treatments
Graph 8 (Right): Total Soil Carbon levels for all grass seed treatments

pH

Graph 9 (Left): Soil pH levels for all poppy treatments
Graph 10 (Right): Soil pH levels for all grass seed treatments

There did not appear to be any trends from either treatment. Potentially the PSW may result in a
reduction in pH, as it is mildly acidic at pH 5.5.

Nutrient Analysis – Soil and Tissue

This discussion focuses on the soil and tissue test results obtained from the PSW treatments, as
appreciable amounts of potentially available plant nutrients were applied. Any trends detected in
the TM21 treatments will be discussed if evident.

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Nitrate

Significant amounts of nitrate were applied with the PSW treatments, and while this did not increase
levels of soil Total Nitrogen, the levels of nitrate detected in the poppy and grass tissues showed an
increasing trend with higher levels of PSW. This indicates that the nitrogen applied with the PSW
was available for plant uptake.
The tissue nitrate levels were considerably higher in the poppy crop compared with the grass seed,
even in the control. This demonstrates the higher nitrogen requirement of grass compared with
poppies, and can be explained by the higher dry matter production associated with grass.
The nitrate levels of the poppies in the 5t/ha and 10 t/ha PSW applications were higher than the
desirable level, while even at 10t/ha of PSW the grass seed was still nitrogen deficient.

Graph 11: Tissue nitrate levels for PSW only.

Phosphorus

Despite the addition of 46 kg/ha of phosphorus with 10t/ha of PSW, this did not increase the
amount of plant available phosphorus according to the Melich 3 extraction test performed as part of
the Agvita soil analysis. This may indicate that the phosphorus being applied with the PSW is not
readily available to plants within the testing time frame.

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The tissue test results did not indicate any increase in phosphorus levels in either the poppy or grass
seed crops. The poppy tissue test results indicated a decrease in phosphorus levels with increasing
application rates of PSW most probably as a result of increase plant growth which diluted the
amount of phosphorus in the plant.

Graph 12: Soil Phosphorus levels, PSW only.

Graph 13: Sap Phosphorus levels, PSW only.

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Potassium

In poppies the levels of soil K decreased with higher levels of PSW, in grass the levels increased. The
grass seed area had a lower initial level of soil K, which then increased with higher application levels
of PSW. It would appear that the grass was unable to utilise the higher levels of soil K due to some
other limiting factor. Another issue was that the seed yields were lower with higher PSW levels
thereby reducing the K requirement.
The poppies reduced the amount of soil K with increased PSW amounts, this is likely to be due to
increased plant growth as indicated by the higher yields.
It would appear that the PSW applied K was highly available to the poppies.
Despite the low levels of soil K, the tissue test results for both poppies and grass were high in K
levels. This may indicate that during the growing season high levels of K was available from the PSW,
this was not residual however and did not remain in the soil when the second soil test was
conducted.
Based on these results, K was not limiting for either the poppy or grass seed crops, despite the soil
test indicating that this may have potentially been the case.

Graph 14: Soil Potassium levels, PSW only.

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Graph 15: Sap Potassium levels, PSW only.

Sulfur

Soil tests indicate that S was not limiting for either crop in the initial soil test, and the PSW did not
increase S levels. The tissue test results indicate that both crops were in the desirable range for all
application rates.

Graph 16: Soil Sulphur levels, PSW only.

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Graph 17: Sap Sulphur levels, PSW only.

Image 1: Lachlan McFadzean collecting tissue samples to be sent off for lab analysis.

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Calcium

Initial Ca levels as indicated by the soil test were below desirable levels for both crops, and the
addition of PSW did not increase soil levels at the completion of the trial.
However it would appear that the PSW was able to satisfy the poppy Ca requirement, with higher
PSW application rates resulting in higher plant tissue Ca levels. Grass has a higher Ca requirement
and the tissue Ca levels were below the desirable levels for all PSW application rates.
The 0 t/ha PSW application rate had the highest plant tissue Ca reading in the poppy treatments,
despite the soil test indicating that Ca would be limiting. This may have caused by the higher nitrate
levels applied with the PSW increasing the growth and diluting Ca levels in the tissue.

Graph 18: Soil Calcium levels, PSW only.

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Graph 19: Sap Calcium levels, PSW only.

Magnesium

The soil test results indicated that the Mg levels were in the desirable range for both crop types and
more was added with the PSW as there is an appreciable amount of Mg in PSW. This was not taken
up by the grass seed crop, but even the 0 t/ha PSW treatment in the poppies resulted in higher than
desirable levels of plant tissue Mg. At the 10t/ha rate of PSW the Mg tissue levels were highest.
Mg levels may be something that needs to be watched when PSW is applied to soils that are already
high in Mg.

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Graph 20: Soil Magnesium levels, PSW only.

Graph 21: Sap Magnesium levels, PSW only.

Zinc

Initial soil levels were in the desirable range, but levels then decreased in both crops at all PSW
application rates, indicating plant uptake of this nutrient.
Zinc levels in the poppy tissue was higher at all levels compared with the grass seed. Poppy tissue
levels decreased with higher rates of PSW. Both crops had tissue levels that were within, or close to

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the optimum range. This is a common result as plant growth can be regulated by the amount of
available zinc to the extent that growth will continue only to a level matched to the amount of zinc
that can be accessed. If more zinc was applied, growth may have been improved without seeing
excessive results in the sap analysis.

Graph 22: Soil Zinc levels, PSW only.

Graph 23: Sap Zinc levels, PSW only.

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Copper

Initial soil levels were below desirable for both grass seed and poppies. The addition of PSW did not
appear to have any effect on soil Cu levels. PSW applications did not appear to have any effect on Cu
tissue levels, Cu was deficient in both crops at all application levels.

Graph 24: Soil Copper levels, PSW only.

Graph 25: Sap Copper levels, PSW only

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Boron

Soil levels were low in all treatments both before and after PSW applications.
Boron was applied to the poppies both with the planting fertiliser and as a foliar application. Poppy
tissue levels were in the desirable range, but were close to being deficient in the 5 and 10 t/ha PSW
treatments. The higher yields obtained from these treatments may indicate that more Boron needs
to be applied. No Boron fertiliser was applied to the grass seed, and all treatments were very low for
this nutrient.

Graph 26: Soil Boron levels, PSW only.

Graph 27: Sap Boron levels, PSW only.

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Molybdenum

No soil test is available to test for Mo.
All treatments in grass seed and poppies were considered deficient for Mo in the sap analysis.

Graph 28: Sap Molybdenum levels, PSW only.

Discussion

Despite the addition of a material high in organic matter, such as PSW at a high rate of 10 t/ha, no
positive effects was seen on the levels of Active or Total Carbon. The 10 t/ha rate did not result in a
higher return in terms of crop yield in this trial, and even higher application rates would be required
to increase soil carbon levels.
The most significant effect on soil carbon observed in this trial was the decrease in Active Carbon
caused by soil cultivation and the most positive effect was a long grass pasture phase, which not
only resulted in higher Active and Total Carbon levels, but also resulted in the highest and most
profitable poppy yield.
The addition of PSW did have a positive influence on yield and returns, where it appeared to be the
nutrients contained in the PSW that was having a significant influence. Nitrogen, being the nutrient

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applied in the highest amounts had a significant influence, however if this was not balanced with
other nutrients then a yield reduction was observed, particularly in the grass seed.
The tissue testing analysis also indicated that a number of trace elements may be limiting for both
grass seed and poppies. The influence of Molybdenum, Boron, Copper and Zinc should be
investigated in more detail for both crops. The results also indicated that at the PSW application
rate of 10 t/ha, phosphorus was deficient in the plant tissue test, so higher levels are required when
nitrogen rates increase.
The results from the TM21 applications on the poppy crops was also significant and resulted in the
highest yield and return from any treatment. As previously discussed it would appear that previous
crop history had some influence here as well, but the yield increase was in the same magnitude as
the PSW applications. The data gathered in this trial was not able to explain the reason for this
result, but it would well be worth investigating further.

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Appendices:

Treatment Map

25

Apendix A – PSW analysis sheet

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Apendix B – Technical Bulletin on TM21

Technical Bulletin on TM 21

TM21 is a bio-stimulant that feeds and increases the population of beneficial micro-organisms in the
soil. Some of the farming practices used in the past and some things that we are presently doing,
though necessary to stay profitable, are destroying the soil structure and the soil microbial life.
Examples include:

- Tilling the soil - Insecticide use
- Chemical use - Deep ripping
- Fertilizer use - Compaction
- Crop rotation - Fungicide use

Once you start losing segments of the micro-life Soil microbes can significantly improve soil
family many other microbes shut down. They structure and stability. The photo on the left shows
need each other to exist. They will stay in a network of fungal hyphae binding soil particles
dormancy until the right conditions in the soil onto wheat stubble. The photo on the right shows
reappear. When you bring back the entire microbial glues produced by soil fungi which help
microbe community by repopulating the soil, bind soil particles into aggregates.
numerous benefits are brought back to the soil
and to the plants that grow in it. Because we
need to do many harmful actions to continue

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farming we should apply TM21 every year.

Benefits

Soil Aeration:
- Microbes and other organisms (e.g. earthworms) all spring back into action. They burrow through
the soil, loosening it as they go. This allows water to run down these tunnels into the sub moisture,
instead of puddling on the surface and evaporating. Roots also follow these tunnels deeper into the
aerated soil allowing them to search for nutrients and moisture more efficiently.
- Bad bugs like cutworms, wire worms, root rot fungus and other grazers and feeders are
anaerobic. They thrive in non-oxygenated environments. Aerating the soil pushes these predators
down out of the rooting zone where the oxygen is low.
- Beneficial microbes are aerobic and like more air. Hyphae start to form on roots extending many
feet in all directions. They are basically root extensions. These hyphae help with the transportation of
nutrients and water. Many of the previously mentioned examples kill off and destroy a lot of the
hyphae.

Improved Nitrogen Efficiency:
- When low micro-life is in place nitrogen mixes with the ground water. Whenever the plant wants
water it is forced to take nitrogen making the plant grow tall and skinny with thin cell walls. This is a
growing problem because thin cells are easy for disease and pests to penetrate. Thin stalks are
inefficient at transporting water to the head on hot days. The water evaporates out of the stalk before
it gets to the head. Stems also lodge easier creating harvest problems. When nitrogen is mixed with
ground water it is more prone to leeching.
- Microbes eat all inorganic nitrogen storing it in their bodies and attaching themselves to the soil
aggregates. The microbes take nitrogen out of the ground water. Therefore, when plants want water
they take up water. When plants want nitrogen or other nutrients they trade sugar to the microbes for
nitrogen. Plants will raise their sugar content to enhance this exchange process. Healthier plants have
higher levels of sugar in them. Increased sugar is a Natural Pest Control. Many predators
(grasshoppers, aphids, moths etc) cannot digest sugar because sugar is a toxin to the bugs.
- Plants now grow as tall as before but with thick cell walls, thick stems, bigger and thicker leaves,
and a much larger and more complex root system. This will allow for more drought tolerance.

Improved Phosphate Efficiency:
- Many microbes do many things:
- Phosphate releasing microbes also come to life. Other products on the market offer these
microbes but they only work for a short period of time, as they have no support structure in place

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