Yield might be king but crop yields don’t tell us whether we are using fertilisers efficiently. To do this we need to look at how well nutrients are making their way into the plant.

All of our trials are plant tissue tested (if we’ve got a crop or pasture to sample). Test results enable meaningful treatment comparisons, confirm which nutrients are limiting production and tell us which ones we need to apply. Soil tests measure supply while plant tests measure availability.

Here’s a snapshot of what we’ve already learnt from plant testing our trials this season.

Bolgart. Lime * potassium (Canola)

Lime has increased potassium uptake. Crop was nitrogen (N) deficient so a top up was applied.

Bolgart. Manganese sources and strategies (Barley)

The choice of a Manganese source is important and an oxide source has been shown to be completely ineffective. Increasing phosphorus (P) inputs has had improved manganese (Mn) uptake. Trial has adequate N. Marginal copper (Cu) and zinc (Zn) levels should be addressed in future years.

Cunderdin. N, K, S & B nutrient omission (Canola)

N, potassumn (K) and sulfur (S) deficiencies confirmed. Marginal B levels indicate some prospects of getting a response to boron (B) fertiliser.

York. Zinc calibration (Wheat v Barley)

Zn responses highly unlikely (despite a 300-400 kg/ha in wheat last year). This indicates significant residual value from a high rate of foliar Zn applied last year.

Corrigin. Potassium with hay in the rotation (Canola)

K deficiency confirmed on a Salmon Gum loam. Responses to K treatments likely.

Narrogin. Potassium calibration (Wheat v Oats)

Unlikely to be as responsive as indicated by soil tests. N top up required. Trace elements will not limit responses to K treatments.

Gnowangerup. N, K, S & B nutrient omission (Canola)

N, K & S deficiencies confirmed. High B levels indicates no prospect of treatment response. High levels of all other trace elements.

Kojaneerup. Long term K strategies (Barley)

K deficiency confirmed. N uptake much better than expected so planned N top up was withheld. Cu levels were low so a foliar Cu spray was applied to protect fertiliser responses. 

Nice K response but yield responses would be less likely without foliar Cu

Mount Barker. N, P, K, S nutrient omission (Canola)

Low S confirmed in the absence of deficiency symptoms. Can’t expect a K response. Boron and Cu marginal. Cu likely to be limiting the next cereal crop. Will apply foliar B test strips.

Mount Barker. No deficiency symptoms but low S and a high N/S ratio indicates S deficiency

Plant tissue testing provides an invaluable guide for better fertiliser decisions. 

CSBP has been tissue testing trials for the last 45 years. That gives us an unrivalled data set to draw on for interpretation of farmer samples through NUlogic.
James Easton
By James Easton
- Senior Agronomist

James has over 30 years’ experience working on soil and plant nutrition (crops and pastures).

He graduated from the University of Western Australia with a degree in Agricultural Science (Honours). He has in depth knowledge of historic fertiliser research trials and has worked closely with many growers, consultants, research institutions and farming groups over the years.

James gets a lot of satisfaction from sharing his knowledge with growers and those who support them. And he enjoys the fact that we are always learning.

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