The influence of canola stubble management on wheat production in the Holbrook area of southern NSW
The key messages outlined in this factsheet are:
- Retaining high stubble loads reduces the amount of nitrogen available to the next crop.
- Reduced available nitrogen in soil can be overcome by applying nitrogen fertiliser.
- Lower amounts of nitrogen fertiliser are needed to overcome immobilisation when stubble is left standing.
- Higher amounts of nitrogen fertiliser are needed to overcome immobilisation when over 5 t/ha of stubble is mulched or incorporated.
- No more than 50 kg N/ha is needed to overcome the detrimental effects on grain yield of retaining heavy stubble loads.
Key results included:
Applying 25 kg N/ha to wheat at Holbrook mitigated the detrimental effects of stubble retention in the less intensive systems (Table 1A). Black text in the table shown where 25 kg N/ha produced grain yields equal or better than those obtained after burning stubble without N fertiliser.
Up to 50 kg N/ha needs to be applied to mitigate the detrimental effects of stubble retention when higher stubble loads are retained using practices that result in stubble being in contact with the soil.