New Horizons Trials Show Promising Results
The New Horizons Trial site at Karoonda has provided some promising results in its first year.
The soil type at the site is a grey shallow sand grading to orange
leached sand, overlying orange brown clay 30-60cms below the
soil surface. For the trials, clay, organic matter and nutrients
have been mixed (spaded) into the top 40 cm with the aim of
increasing the crop’s root depth and density.
Despite the damage of frost and the dry spring, some of the
treatments yielded over triple that of the control (0.55 t/ha).
The best grain yield of 2.05 t/ha was from the spaded+organic
matter+ nutrition treatment. The only treatment that did not
give a grain yield significantly more that the control was the
shallow clay treatment where clay was only mixed to 10 cm
(note the control represented district best practice).
Soil profile at the Karoonda demonstration site
Crop growth, measured as dry matter production in early August, showed the crop’s potential that
was damaged by the frosts and dry spring. The spaded+organic matter+nutrition dry matter
production of 2.21 t/ha was 4 times that of the control (0.56 t/ha).
Treatment results for grain yield and dry matter production compared to the control at Karoonda 2014 season
control
deep nutrition
shallow clay
shallow clay+deep nutrition
spaded
spaded+OM
spaded + nutrition
clayed+spaded
clayed+spaded+nutrition
spaded+OM+nutrition
clayed+spaded+OM
Note: Yield is solid colour and dry matter hatched
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
clayed+spaded+OM+nutrition
times control
Karoonda - Yield and dry matter compared to control
There was not a consistent trend between treatments and the effect of protein and screening. The
grain protein and proportion of screenings varied with the highest protein achieved on the
clayed+spaded+organic matter+nutrition treatment (14.1%) and the lowest (12.3%) on the shallow
clay+deep nutrition treatment. The control’s protein percentage was 13.2%. The highest proportion
of screenings (5.7%) was from the shallow clay treatment and the lowest (2.8%) from the
spaded+nutrition treatment while the control’s screenings percentage was 4.4%.
Karoonda - Grain protein and screenings
control
deep nutrition
shallow clay
shallow clay+deep nutrition
spaded
spaded+OM
spaded+nutrition
clayed+spaded
clayed+spaded+OM
clayed+spaded+nutrition
spaded+OM+nutrition
16
14
12
10
8
6
4
2
0
clayed+spaded+OM+nutrition
Percentage
Protein solid colour and screenings hatched
Grain protein and screening percentages of all treatments at Karoonda 2014 season
Across the three New Horizons trial sites (Karoonda, Cadgee in the South East and Brimpton Lake on
Eyre Peninsula), spading generally increased yields with organic matter further boosting yields.
However, there is no clear reason yet for why these treatments worked – does spading itself reduce
compaction, enabling better root growth or does it mix nutrients deeper into the profile, effectively
increasing the soil volume that roots can draw nutrition from?
Further testing this season will help us better understand these initial encouraging results.