level ii agricultural business operations. scale proposed by the dutch phytopathologist, jan c....
TRANSCRIPT
Level II Agricultural Business Operations
Scale proposed by the Dutch phytopathologist, Jan C. Zadoks
Know as Zadoks scale, it gives the plant a figure based on the current growth stage of the plant.
Scales goes from 00-99.
Knowing the stages of development of a crop is critical in many management decisions that growers make.
Eg, Nitrogen application GS21 Herbicide application GS11
Fungicide application GS32Growth regulator GS32
0
50
100
150
200
250
Feb Mar Apr May Jun Jul Aug
N U
ptak
e (k
g/ha
)
GS 31
GS 39
GS 61
Harvest
Slow Rapid Slow
40 % of total N uptake in 4 weeks
17 % of total N uptake
T1, T2 & T3 are linked to timing of fungicide spraying.
T1 is generally GS 32-33
T2 is GS 39
T3 is a ear wash at GS 65
Some other T values have been developing e.g. T0.5, T1.5 etc. Becoming more popular in NI
Link from HGCA website.
http://www.hgca.com/media/180128/g49-cereals-growth-stages-a-guide-for-crop-treatments.pdf
Seedling Growth 11-19 Tillering 20-29 Stem Elongation 30-39 Booting 41-49 Ear Emergence 51-59 Flowering 61-69 Milk Development 71-79 Dough Development 81-89 Ripening 91-99
GS10 First leaf through coleoptile
GS11 First leaf unfolded (ligule visible)
GS13 - 3 leaves unfolded
GS15 - 5 leaves unfolded
GS19 - 9 or more leaves unfolded
GS20 Main shoot only
GS21 Main shoot and 1 tiller
GS23 Main shoot and 3 tillers
GS25 Main shoot and 5 tillers
GS29 Main shoot and 9 or more tillers
GS30 Ear at 1cm (pseudostem erect)
GS31 First node detectable
GS32 Second node detectable
GS33 Third node detectable
GS37 Flag leaf just visible
GS39 Flag leaf blade all visible
Very Important Period◦ Fungicide Timing◦ Growth regulator
For a quick, but crude assessment, fold back the leaf sheaths then count the slight 'bumps' caused by each node.
The exact stage is revealed by stripping off leaves and cutting the main stem longitudinally with a sharp knife.
GS41 Flag leaf sheath extending
GS43 Flag leaf sheath just visibly swollen
GS45 Flag leaf sheath swollen
GS47 Flag leaf sheath opening
GS49 First awns visible (if an awned variety) Barley only
GS51 First spikelet of ear just visible above flag leaf ligule
GS55 Half of ear emerged above flag leaf ligule
GS59 Ear completely emerged above flag leaf ligule
GS61 Start of flowering
GS65 Flowering half-way
GS69 Flowering complete
GS71 Grain watery ripe
GS73 Early milk
GS75 Medium milk
GS77 Late milk
GS83 Early dough
GS85 Soft dough
GS87 Hard dough (thumbnail impression held)
GS91 Grain hard (difficult to divide)
GS92 Grain hard (not dented by thumbnail)
GS93 Grain loosening in daytime
Correct timing of sprays and fertiliser treatments is critical to success in growing cereals.
Many instructions and guides state ‘Apply at GSXX.”
Take 5-10 typical plants from across the field, ideally digging them up rather than pulling up to avoid damaging stems and leaves.
Knowing the growth stage is important to ensure that timing of pesticides are applied in line with manufactures recommendations.
Correct timing can have a bigger impact on crop response/performance than product type!