Broad constraint resources are outlined in the Agronomists Toolkit. Specific constraint categories are listed below:

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Fertiliser toxicity

Constraint - Fertiliser toxicity

Care must be taken to seperate fertiliser form seed when sowing. Canola seedlings are particularly susceptible to damage.

Symptoms

  • Delayed or decreased germination

  • Seedlings are weakened and stunted

  • Canola has stunted taproots

  • Poorer plant growth can be seen along rows

Damage

  • Fertiliser too close to the seed can cause seed to dessicate, or 'burn'

  • Fertiliser that releases free ammonia can cause ammonia toxicity in the seed

  • Stress, sandy soils, wider row spacings, and dry soils increase potential for damage

  • Urea is most likely to cause damage

  • Up to a 40 to 50 percent yield reduction can occur if urea toxicity occurs  

Management

Modified seeding equipment to band fertiliser away from the seed, topdressing, careful consideration of fertiliser rate, and sowing in optimal environmental conditions can all decrease the likelihood of fertiliser toxicity.

 

 

Links and Resources

AOF - Fertiliser toxicity

2 page PDF. Description, impact, contributing factors, and management.

CSIRO - Fertiliser toxicity

2 page PDF. Introduction, minimum tillage, sowing system, narrow spread system, sowing into moist soil, fertiliser placement, and Mallee clay loam trial. Published 2004.

DAFWA - Seedling fertiliser damage

Introduction, contributing factors, what to look for, what else it could be, and management strategies. Page last updated 2014.

GRDC - Best Practice Management Guide. Fertiliser toxicity

Page 24. Fertiliser management at sowing. Published 2009.

GRDC - Fertiliser Toxicity Fact Sheet

4 page PDF. Key points, selecting fertilisers and rates, crop type, soil type, environment, machinery configuration, and frequently asked questions. Published 2011.

IPNI - Care with fertiliser and seed placement

Introduction, type of crop most affected, type of fertiliser, soil type, environment, machinery configuration, and fluid fertilisers. Published 2013.