Riverine Plains Blog

Key messages:

• canola crops are especially vulnerable to sulfur deficiency
• leaching and high rates of plant removal over the past few years have likely reduced soil sulfur levels
• incremented soil testing to a depth of 60-80cm will identify the quantity and location of sulfur in the soil
• understanding what’s in the ‘bank’ can help farmers make timely and economical fertiliser decisions

Sulfur (S) is an important nutrient for grain crops as it is used in chlorophyll formation and plant development. Canola has a higher requirement than wheat or legume crops for sulfur thanks to its oil and protein production.

Key messages

• Understanding the scale and depth of soil constraints is key to an effective amelioration program
• Incremental sampling to depth provides more information than traditional 0-10 cm tests
• Seek advice before beginning an amelioration program

Summer and early autumn provides an opportunity for Riverine Plains farmers to treat soil constraints, such as acidity and sodicity, between winter crops.

So, what are the issues to consider?

Key Messages

• Stubble retention has many benefits for soil health, can improve soil moisture and help maintain soil organic carbon levels
• Different methods of sowing and equipment result in different thresholds for change in terms of maximum stubble load that can be retained
• If full stubble retention is not feasible due to machinery, weeds or disease constraints, there are other options such as shallow incorporation, slashing straw or cutting short at harvest which can reduce the frequency of burning

Benefits of Stubble Retention

Retaining stubble can reduce the impacts of soil erosion. At least 70 per cent ground cover minimises water erosion risk and 50 per cent ground cover minimises wind erosion risk. Stubble height should be at least one-third of the width of crop rows. In general, the shelter provided by a barrier is approximately three times its height; 10 cm tall stubble will protect the adjacent 30 cm of topsoil. (Source: Managing stubble | General agronomy | Crop production | Grains, pulses and cereals | Crops and horticulture | Agriculture Victoria )

Key Messages:

• Carbon is present in the soil in many different forms.
• Including a pasture phase and pulses/legumes in the cropping rotation is essential to improve soil organic matter and nitrogen levels, promote microbial activity and ultimately increase soil organic carbon. 
• Evaluating management practices to increase soil carbon is necessary to ensure they are economically viable for a farming business.
• Several environmental factors (rainfall, evaporation, solar radiation, and temperature), as well as soil type, nutrient availability and land management influence maximum soil organic carbon storage capacity 

 

What Is Soil Carbon?

Soil carbon can occur in organic and inorganic forms.

Riverine Plains recently hosted a soil health webinar as part of a project supported by the Foundation for Rural and Regional Renewal (FRRR), through funding from the Australian Government’s Future Drought Fund.