Other management practices to lower risk
The following management practices may lower frost risk but have had varying levels of success:
- Sow wider row spacings on heavy soils - may allow more airflow through crops, thus allowing soil heat to rise up to canopy height during frosts. Previous trial work has shown that wide-row sowing has debatable effectiveness on both sandy and heavy-texture soil. There is also a 1% yield loss per inch increase in row spacing and compromised weed control.
- Roll sandy and loamy clay soil after seeding - this practice consolidates moist soil providing a reduced surface areas. This enables more radiant heat to be trapped and stored during the day compared with dry, loose soil. Moist and firm soil is a better conductor of heat and will cool slowly because heat removed at the surface by radiation is replaced in part by heat conducted upwards from the warmer soil below. A roller is usually towed behind the seeder machinery or it can be done post-emergent. Rolling is not usually recommended due to the extra expense, extra time required, debatable effectiveness, inter-row weed germination and increased wind erosion risk on susceptible soil types.
- Cross-sowing - crops are sown twice with half the seed sown in each run producing an even plant density and generating a complete crop canopy that still allows air flow. Two trials across two seasons have been carried out in WA. In one trial a conventionally sown wheat crop was compared with a cross-sown wheat crop at varying sowing rates. The conventionally sown crop experienced more frost damage and lower yields at all sowing rates compared with cross-sown crops. Cross-sowing is not usually recommended due to the additional cost and time taken to sow the paddock twice and the minimum trial work that has been done to look at the impact of cross-sowing.
Frost is difficult to manage and in some seasons damage will be unavoidable. An integrated approach is required to minimise the risk of frost whilst setting your paddocks up to reach their yield potential. Where you will see greater gains are in paddock choice/zoning, crop and variety choice and manipulating the canopy.
References
- Anderson WK, Garlinge JR (Eds) (2000) The wheat book: principles and practice. Agriculture Western Australia and the Grains Research and Development Corporation.
- Rebbeck MA, Knell G (2007) 'Managing frost risk: a guide for southern Australian grains', (Ed. Reuter D) (Grains Research and Development Corporation, South Australian Research and Development Institute: Adelaide).
- White C (2000) Pulse and Canola—Frost Identification: The Back Pocket Guide. Department of Agriculture and Food, Western Australia. Bulletin 4401.
- March T, Laws M, Eckermann P, McGowan P, Diffey S, Cullis B, Maccallum R, Leske B, Biddulph B and Eglinton J (2016) Ranking cereal varieties for frost susceptility using frost values Northern Grains Research and Development Corporation Updates Paper.
- Ma Q, Bell R and Biddulph B (2018) Potassium application alleviates grain sterility and increases yield of wheat (Triticum aestivum) in frost-prone Mediterranean-type climate. Plant and Soil, 434 (1-2). pp. 203-216.