Diagnostic agronomy,Dubbo, 18th October 2010

Allan Mayfield,Clare, SA

Nutrition

P - P audits, plant tests, P rate test strips

N - Soil N, plant NIR & sap N, NDVI (GreenSeeker), look at it!,Baldock model, Yield Prophet, experience

Other nutrients – visual symptoms, plant tests (diagnosis & monitoring)

Nutrition management in zones

Soil water

Yield Prophet Sensors – eg Sentek Metal push probes

Using zones to improve soil water assessments

Weeds

Acceptable weed control is typically well below the economic thresholds for yield loss

For herbicide resistance – Quick-Test

(green plants), seed tests, herbicide test strips

Weed control according to zones

Ryegrass % cover/canola % cover

DiseasesDiseases Pre-emptive for root diseases – Predicta B test,

observations in previous crop(s) For foliar diseases – when symptoms or pre-

emptive. Fungicide use now very common.

Varietal resistance can be a major factor in crop selection (eg CCN, stem rust, canola blackleg)

Insects Some pre-emptive treatments used, especially for

canola & virus control, otherwise, treat as needed.

Close monitoring of crops can be critical

Need to identify beneficials as well as pests Gaps include thresholds - the understanding of

effect of beneficials, and the impact of pesticides

Grower’s situation & attitude to risk is important

Retrospective monitoring - Improvements in water use

efficiencyWater use efficiency (kg/mmGSR), 5 year average, wheat, Redhill, SA.

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