SulFer 85 Soil Acidification
SOIL
ACIDIFICATION
The ability
of a soil amendment to change soil pH is dependent on several factors including
soil texture, initial pH, buffering capacity of the soil, base saturation in
the soil, moisture content and temperature of the soil.
Sandy soils
tend to have higher evaporation rates. This can result in water being pulled
from lower depths and bringing salts and hydroxyl compounds which can slowly
increase pH of the soil.
Initial pH
is determined by parent material, if this is strongly acid or alkaline greater
quantities of amendments will be required to change pH.
Buffering
capacity is the soils ability to resist change, heavy soils resist change more
than light soils.
Most
amendments depend on activity of soil organisms to break down and affect pH,
this activity is greater in warm moist conditions.
Elemental S
has to be oxidised to sulphate before it is available to the plant, the smaller
the particle size the faster this occurs
SOIL AMENDMENT WITH ELEMENTAL S
Approximately 312lbs of calcium carbonate in liming material is required to neutralise the acidifying effect of 100lbs of elemental S. Approximately 112lbs of calcium carbonate equivalent in liming material is required to neutralise the acidifying effects of 100lbs of ammonium sulphate. Thus approximately 3 times as much ammonium sulphate is required as elemental S to have the same acidifying effect.
Sulphur needed to lower pH to about 6.5
|
pH of untreated soil |
Method of
Application |
|||
|
Broadcast kg/ha |
Banded kg/ha |
|||
|
Sandy soils |
Clay soils |
Sandy soils |
Clay soils |
|
|
9.0 |
2246 |
3368 |
878+ |
878+ |
|
8.5 |
1660 |
2246 |
683-878 |
878+ |
|
8.0 |
1123 |
1660 |
341-585 |
683-878 |
|
7.5 |
439 |
683 |
244-292 |
341-585 |
Trial ProtocolAlberta:
SulFer 85 was applied to the surface of a black chernozemic soil at the Ellerslie Research station located south of Edmonton, Alberta. The product was applied at a rate of 300, 700, and 1200 lbs/acre. The SulFer 85 was allowed to sit on the surface for a number of days prior to incorporation. The pH was measured prior to application (July 19) and two months later on September 22.
Results:
|
|
September 22 |
||
|
SulFer 85 Rate (lb/ac) |
Original Soil pH (0-6") |
Soil depth (inches) |
Soil pH |
|
0 |
5.9 |
0-3 |
5.8 |
|
|
|
3-6 |
5.9 |
|
300 |
6.0 |
0-3 |
5.5 |
|
|
|
3-6 |
5.9 |
|
700 |
6.1 |
0-3 |
5.4 |
|
|
|
3-6 |
5.8 |
|
1200 |
6.2 |
0-3 |
5.3 |
|
|
|
3-6 |
5.7 |
Comments:
A lack of precipitation following application did not result in good dispersion of the SulFer 85 particles. However, it is evident that significant amounts of SulFer 85 had oxidized over the 2 month period despite the hot dry conditions. The SulFer 85 was successful in lowering soil pH.
Trials in the UK in July-Sept 2000, showed that application of 90k/ha SulFer 85, applied over a two month period as 3 equal applications to golf greens reduced pH from 7.9 to 6.2 and from 7.1 to 6.0.This is achieved through the rapid breakdown of the prill allowing oxidation of the Sulphur to sulphate with the subsequent reduction in pH.
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