Timaru 4 Nov 2016
Relationships between total dry matter yield
and height of dryland lucerne
Photo: KM Pollock
Lincoln University
A Mills, M Smith & DJ Moot
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Publication details
This presentation was made at the 78th annual New Zealand
Grasslands Conference held at Caroline Bay Hall, Timaru 2-4 Nov
2016.
It is associated with the following publication:
Mills, A., Smith, M.C., Moot, D.J. 2016. Relationships between
dry matter yield and height of dryland lucerne. Journal
of New Zealand Grasslands, 78, 185-196.
Introduction
• Destructive measures of yield are time consuming
• Non destructive methods must be reliable,
repeatable & accurate
• Relationships between total yield and lucerne
height evaluated for a dryland monoculture over
six years
Pasture probe
Rising plate meter
Height stick
Materials & Methods
• 711 paired data points from 2009 to 2016
• Height and total yield from a 0.2 m2 quadrat.
• Three quadrats from low, medium and high areas.
• ‘Stamina 6GT’ ~50% of samples
• 66% pre-graze samples from rotationally grazed area
• 101 samples post-graze residuals - analysed separately
• 142 samples from the SS and Semi SS treatments
Results
• Average lucerne height (cm) explained 58%
(adjusted R2) of the observed variation in total DM
yield (n=468)
• Inclusion of Season and Year as explanatory
factors increased the adjusted R2 to 0.78
• Data were recoded into 14 year/season
combinations. The grouped linear regression had
an R2 of 0.84
Total DM yield (kg/ha)
Pre graze Results – Spring
2009/10
2013/14
Yield = 104x
(R2 = 0.71)
Height >20 cm Yield = 1849 + 48x
(R2 = 0.31)
8000
8000
Stamina 5
Stamina 6GT
Runner
AgR (HP)
Stamina 5 (4-pdk)
Stamina 6GT (4-pdk)
Runner (4-pdk)
6000
Kaituna
Stamina 5
Stamina 6GT
Runner
6000
4000
4000
2000
2000
Stamina 6GT SS
Stamina 6GT Semi SS
0
0
0
20
40
60
80
100
0
20
Lucerne height (cm)
40
60
80
100
Spring
Kaituna
Stamina 6GT
Stamina 5
Rhino
Runner
AgR (GT)
AgR (HP)
Stamina 6GT (SS)
Stamina 6GT (Semi SS)
Total DM yield (kg/ha)
8000
6000
4000
Spring Total DM yield = 94.2x (R2 =0.54)
2000
0
0
10
20
30
40
50
60
70
Lucerne height (cm)
Mills et al. 2016
Total DM yield (kg/ha)
Summer
8000
6000
Kaituna
Stamina 6GT
Stamina 5
Rhino
Runner
AgR (GT)
AgR (HP)
Stamina 6GT (Semi SS)
Summer Total DM yield = 75.2x (R2 =0.60)
4000
2000
0
0
10
20
30
40
50
60
70
Lucerne height (cm)
Mills et al. 2016
Total DM yield (kg/ha)
Autumn
Autumn Total DM yield = 54.4x (R2 =0.52)
Kaituna
Stamina 6 GT
Stamina 5
Rhino
Runner
AgR (GT)
AgR (HP)
Stamina 6GT (SS)
Stamina 5 (SS)
Runner (SS)
Stamina 6GT (Semi SS)
8000
6000
4000
2000
0
0
10
20
30
40
50
60
70
80
Lucerne height (cm)
Mills et al. 2016
Conclusions
• Incorporation of Year and Season into the model increased the
overall amount of variation accounted for from 58% to 84%.
• For on-farm application lucerne yield can be estimated at
– 95 kg DM/cm in spring,
– 75 kg DM/cm in summer and
– 55 kg DM/cm in autumn
– there was considerable variation around these values.
Acknowledgements
• This work was undertaken as part of Phase II of the Pastoral 21
Programme, funded by the Ministry for Business, Innovation &
Employment; DairyNZ; Beef + Lamb NZ; and Fonterra.
• Mr Roland Stead provided additional financial support.