The Wet Season

Welcome to 2022! Things are looking good for a prosperous year in the agriculture industry.

We have gathered some interesting stats on the predicted extreme weather season risks, including flood, fire and tropical cyclones.

Australia has entered its peak high-risk weather season, which typically runs from October to April. The Bureau of Meteorology’s Severe weather outlook (released in October 2021) ranked widespread flooding, coastal flooding and tropical cyclone as likely threats in spring and early summer 2021–22 in northern Queensland, southern New South Wales, Victoria and Tasmania (Figure 1.3).

Figure 1.3 National severe weather outlook summary, October 2021 to April 2022

Source: Bureau of Meteorology.

The risk of flooding and storms remains high throughout Queensland and in northern and coastal New South Wales.

The last back-to-back La Nina event in Australia was from 2010 to 2012 and resulted in one of the wettest 2-year periods on record. Record rainfalls occurred in many states and caused widespread flooding. In the 2010–11 tropical cyclone season, the number of tropical cyclones recorded in the Australian region was near normal. However, five of these tropical cyclones were categorised as severe, which is above the average number of severe cyclones. This included Severe Tropical Cyclone Yasi, which caused widespread damage to Far North Queensland. Similar weather events may occur following the establishment of the 2021–22 La Nina event in November.

The impacts of these weather events on agricultural production will vary depending on their severity and extent. Flooding events are usually restricted to low-lying and riverine areas. They can cause infrastructure and livestock losses, and disruptions to supply chains. For crops, heavy rainfall associated with thunderstorm activity close to harvest primarily effects the quality rather than that quantity of crops during that production season. However, heavy rainfall can benefit future production because it improves soil moisture.

Tropical cyclones can affect power availability for food storage and packaging activities, and fruit and vegetable production and distribution. Severe storms can occur in all agricultural regions. They can cause power outages, decreased dairy production and storage capabilities, damage to infrastructure, and disruption of supply chains. A return of La Nina conditions during late spring and summer 2021–22 and a weak negative Indian Ocean Dipole are expected to bring above average rainfall to eastern and northern Australia.

The Bureau of Meteorology’s forecast indicates a 75% chance of receiving between 100 mm and 300 mm across large areas of eastern and northern Australia between December 2021 and February 2022 (Figure 1.6). Rainfall totals greater than 300 mm are likely across the tropical north and much of the eastern coastline of Australia and are associated with the onset of the northern wet season and the Australian monsoon. These high rainfall totals are almost equivalent to the seasonal median (between 1990 and 2012) and represent an excellent start to the 2021–22 summer cropping season in eastern Australia and wet season across northern Australia. December to February rainfall totals is likely to be sufficient to sustain above average crop and pasture production through summer.

Figure 1.6 Rainfall totals with a 75% chance of occurring, Australia, December 2021 to February 2022.

Floods, fires, tropical cyclones and severe storms are likely during Australia’s 2021–22 high-risk weather season (October 2021 to April 2022) and may affect agricultural production and supply chains. This wet rainfall outlook for New South Wales and Queensland associated with the onset of La Nina, coupled with well above average rootzone soil moisture levels may led to localised crop losses due to flooding, limited paddock access to complete winter harvest activities and complete summer planting programs.

We all know that lime increases the pH of acidic soil, reducing soil acidity and increasing alkalinity. It provides a source of calcium for plants, improves water penetration for acidic soils, improves the uptake of major plant nutrients (nitrogen, phosphorus, and potassium) of plants growing on acid soils. However, we should remember that we really shouldn’t apply lime if we know heavy rains are predicted. If possible, apply lime when it has not rained recently, and no rain is in the forecast. Wait 1–2 days after rain before spreading lime. This gives the soil time to shed excess water. If you must spread lime when rain is in the forecast, make sure is very light rain.

Here’s to a happy and prosperous 2022, from all the team at Townsville Lime.