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1999 WANTFA / Aglime trials: Tillage treatments

 

Aglime of Australia's R & D program is designed to identify the many benefits and also any problems that may be associated with liming under WA wheatbelt conditions.

 

Five new trials were set up in 1999. Results from 2 trials at Wongan Hills are given in Aglime Action No 16. Results for the three tillage trials are given below.

 

WANTFA / Aglime Trials

Many farmers are concerned that no till farming might delay the onset of yield increases from liming. Aglime limesand may dissolve slower under no till due to reduced physical mixing with soil resulting in less contact between Aglime particles and soil acids

 

Aglime of Australia is working with the Western Australia No Till Farmers Association to set up and monitor 3 trials at Meckering over the next 5 years. These trials will measure the effect of different tillage systems on the time taken for Aglime to dissolve and move through the soil profile and the effect on yield in different rotations.

 

The trial sites are located in a paddock that had received 1 t/ha of Aglime limesand previously in 1994.

 

In March 1999, just prior to liming the trials, pH’s were around 4.8 in the topsoil (0-10cm) and 4.5 in the midsoil (10-20cm).

 

Aglime treatments applied in March 1999 by Hollett Spreading Service are: 0, 1, 2 and 4 tonnes/hectare.

 

Tillage Treatments

 

Great Plains triple disk

8 inch spacing (TD)

 

Knife points, 9 in spacing

with press wheels (KP)

 

Direct drill, full sweep points, 7 inch spacing, covering harrows (CT)

In 1999 all trials were sown to wheat with no significant yield increase due to Aglime. As the entire site was limed previously and is moderately acid (topsoil pH 4.8), yield responses aren’t expected until the second or third year of these trials.

 

Results

Results presented in this newsletter are averaged over the three trials as the 1999 treatments and rotations were the same.

 

 

 

 

 

 

 

 

 

 

 

 

Aglime limesand significantly increased topsoil pH in all tillage treatments

 

 

 

 

 

 

 

 

 

 

 

 

 

However midsoil pH increased more significantly with knife points and

conventional tillage

 

 

At the 1t/ha Aglime rate, there was no difference between the 3 tillage treatments in changing topsoil pH. However, at the 2 and 4t/ha rates, the pH change was less with the triple disk machine.

 

As expected, the higher rates of Aglime increased both topsoil and midsoil pH the greatest.

Aglime should continue to dissolve and leach down the soil profile over the next few years. Further increases in pH in the top and midsoil depths can be expected.

 

It is evident from these trials that no till systems, especially knife points, allow a significant amount of Aglime limesand to dissolve in the surface and leach deeper into the soil.

 

It is possible that the very fine particle size of Aglime limesand along with the relatively coarse structure of these soils has allowed Aglime to move through the soil profile where there has been minimal disturbance to the soil. With coarser limes or in finer textured soils, this movement may not occur as readily.

 

Recommendation

No-till machinery, especially knife points are suitable to use when liming with 1 to 2 t/ha of Aglime limesand.

 

Acknowledgements

WANTFA & GRDC

Hollett Bros - Cunderdin (donation through assisting with Aglime transport costs)

Hollett Spreading Service -Cunderdin (donation through spreading Aglime on trials)