Can you base your Calcium [Lime] needs on pH alone? [No!]
Over fifty percent of agricultural crops and high production pastures grow best within a critical range
of Calcium levels being between 60-70%* and Magnesium
10-15%* base saturation. It has been proven, again and again, that a
balanced approach to soil chemistry is the key to successful plant growth and that when this occurs soil
pH, aeration, drainage, structure and beneficial soil biology also improve. Thus, if soil chemistry is
balanced, especially calcium, improved productivity and plant and animal health will be a natural outcome.
In Table 1, 'A' is a balanced, healthy, productive soil
being Ca 68%, Mg 12%, K 2-5%, & Na>1.5%*. As discussed previously, this balance was identified
after intensive research based on analysing soils that were naturally productive and healthy, and comparing
them with un-productive soils. Notice that Calcium is the major Cation in a healthy soil. Calcium promotes
good crumb structure in soil and is important for numerous other soil processes.
When Hydrogen occupies 12% of the CEC [Cation Exchange Capacity], soil pH is 6.2. If the soil fertility
balance of soil 'A' is changed by replacing Calcium with Magnesium on 20% of the CEC, the result is soil
'B' with High Magnesium levels. This type of black soil is tight/hard when dry,
and sticky when wet. This is a medium productivity soil that is difficult to manage. The Hydrogen %
is unchanged so soil pH is still 6.2, but the soil is deficient in Calcium and needs Lime.
Removing Magnesium from 20% of the CEC of soil 'B' and replacing it with Sodium. The results in soil
'C', which is an unproductive saline soil. Note that all three soils have
the same 6.2 pH!
The decision as to how much Lime/Dolomite to be applied is calculated by subtracting the Calcium value
found on the soil audit from the desired Calcium value [68%] according to the TEC. This ensures that
light sandy soils do not get over limed and heavy soil can be budgeted to receive applications over a
number of years. This same technique is also used for costly trace elements and can save hundreds of
dollars on wasted fertiliser.
The following Table [1] shows that it is possible to have the same pH of 6.2 in healthy,
productive soils [A], a high Magnesium soil [B] and
saline unproductive soils [C].
TABLE 1
|
Soil A |
Soil B |
Soil C |
|
Balanced |
High Mg |
High Sodium |
| Nutrient |
Percent of TEC |
| Calcium [Ca++] |
68% |
38% 6 |
38% 6 |
| Magnesium [Mg++] |
12.0 |
42.0 6 |
22.0 6 |
| Potassium [K+] |
5.0 |
5.0 |
5.0 |
| Sodium [Na+] |
1.5 |
1.5 |
21.5 6 |
| Trace Elements |
1.5 |
1.5 |
1.5 |
| Hydrogen [H+] |
12.0 |
12.0 |
12.0 |
| TOTAL |
100.0 |
100.0 |
100.0 |
| pH |
6.2 |
6.2 |
6.2 |
Adapted for Building Healthy Soils and Plants, Tony De Vere [1995] Unpublished.
Calcium in the Soil
Dr William Albrecht called calcium "The Prince of Elements".
Arden Anderson [1998] takes the modern view: Calcium is THE KING OF ELEMENTS.
"Calcium is at the head of the list of the strictly soil-borne elements required in the nourishment of Life"
[From the Albrecht Papers Vol 1. p.144, 1996] For further information on the importance of Calcium please
read Albrecht Papers Vol 1. p.144, 1996 [Acres USA]. The title is simply named: Calcium and is reputed to
be one of Albrecht finest presentations.
Calcium is important because it is the dominating cation [said "cat" "iron"] or positive [+] element in
a healthy balanced soil. Calcium can potentially have a beneficial effect on biological, physical and
chemical properties of your soil if it is needed. Gilbert [1957] notes that Albrecht believes that
calcium deficiency is the number one plant nutrient problem in agricultural production.
The information contained in this publication has been formulated in good faith, the contents do
not take into account all the factors which need to be considered before putting that information
into practice. Accordingly, no person should rely on anything contained herein as a substitute for
specific professional advice.
S.O.S. Rev 9.2 All rights reserved.
Contact: www.healthyag.com © Gwyn Jones 2001
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