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1999 Wongan Hills field trials

 

Wheat at Wongan Hills

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 farming conditions.

 

Five new trials were set up in 1999. The results of two trials located at Wongan Hills are given below. The others are reported in Aglime Action No 17.

 

Wongan Hills Aglime / Logran® Trials

Two new trials are aimed at checking if Aglime increases the soil pH sufficiently to cause ‘carry over’ of sulfonyl urea herbicides.

 

Both trials are on Joe Steenson’s farm, north east of Wongan Hills. Aglime’s limesand was spread in April 1999 at 2 and 4 t/ha rates to compare with a control of 0 t/ha These treatments were replicated 3 times.

 

Both trials were sprayed on 21st April 1999 with Logran® at 35g/ha in 50l/ha of water. The trials were resprayed on 18th August 1999 with 15g/ha of Logran® in 50l/ha of water.

 

Any carry over effect of Logran® due to the higher soil pH from liming will be measured in canola and serradella to be sown in 2000.

 

Trial 1
The first trial was on a good sandy loam with topsoil (0-10cm), midsoil (10-20cm) and subsoil (20-30cm) pH’s around 4.5, 4.7 and 5.5 respectively.

The trial was tilled twice with 7 inch points prior to sowing Calingiri wheat with 10 inch spacing knife points and press wheels. It received 60kg/ha potash and 60kg/ha urea incorporated before sowing, 60kg/ha DAPSCZ at sowing and 40kg/ha urea 3 weeks after sowing.

 

When harvested in November, the unlimed control plots averaged 2.74 t/ha. Average yield on the 2 t/ha limed plots was 3.18t/ha (0.44t/ha or 16% higher) while the 4t/ha limed plot’s averaged 3.26t/ha (0.52t/ha or 19% higher)

Trial 2

The second trial was on a deep sand with topsoil (0-10cm), midsoil (10-20cm) and subsoil (20-30cm) pH’s around 4.5, 4.3 and 4.3 respectively. Note that the subsoil (20-30cm) pH in trial 2 was around 1.2 units lower than trial 1.

 

Trial 2 was treated the same as trial 1 except it had only 1 tillage with 7 inch points prior to sowing with Arrino wheat, and no potash was applied.

 

Yield on the unlimed plots averaged 0.84t/ha. The 2 t/ha plots yielded 0.99t/ha (0.15t/ha or 18% higher) and the 4 t/ha plots averaged 1.09t/ha (0.25t/ha or 30% higher)

1999 Economic Returns

The returns from liming in the first year were outstanding. The figures used in the analysis were $160/t return for wheat and $25/t full cost for Aglime, supplied, transported and spread.

 

In trial 1, the 2t/ha Aglime rate returned $70/ha in this first year and would have cost $50/ha. A profit of $20/ha was achieved.

The 4 t/ha rate would have cost $100/ha and returned $83/ha or 83% of its full cost in this first year.

 

In trial 2, the 2t/ha rate returned 50% of the liming cost and the 4 t/ha rate returned 40% in this first year.

As the returns from liming continue for at least 15 years (and probably 20 or 30 years) all of the Aglime rates in both trials will return a considerable profit in both the short and long term.

 

These results are typical of the many field trials conducted by Aglime of Australia over the past 20 years. Liming better soil types (that are acid) generally produces the greatest profit. Poorer soil types also respond to liming but with smaller profits.

 

Recommendations
The priorities for liming are:

 

Lime Soils with the lowest pH
Within low pH soils, lime better soil types first

 

Acknowledgements

Joe Steenson, Wongan Hills.