The use of irrigation water and the weather conditions will have an impact on the establishment and growth of pastures during autumn and spring.
Due to higher temperatures, sowing may need to be delayed allowing for improved sowing conditions as high temperatures will reduce germination rates and pasture vigour, in turn reducing pasture density, the total pasture grown, and tonnes grown per megalitre of water.
The ideal soil temperature varies with species: with rye-grass and clovers, ideal germination soil temperature is between 20°C and 25°C; Persian and Shaftal clover can withstand higher soil temperatures of up to 35°C; oats have an ideal soil temperature range of 10 to 25°C; and wheat and barley prefer temperatures a couple of degrees lower.
The amount of irrigation water available may impact the timing of sowing, the area sown at a given time and what you sow, and plans for the following spring should also be considered when selecting varieties.
Short season annuals and Italians tend to be cheaper than long season ones, but if winter and spring are good what is the value of the late spring feed to you?
Selecting long season varieties, although they may be more expensive, allow flexibility in the system and can produce until late November/early December, which allows an extra grazing or two.
On the other hand, if water is short, they can be finished watering earlier.
The time of irrigation start-up will impact the number of irrigations required and how much water will be needed, with the first irrigation typically using 1.5Ml/ha with subsequent irrigations requiring 0.5Ml/ha, depending on soil type and irrigation layout.
Staggering irrigation start-up helps to develop the feed wedge by having the growth stage staggered and helps to reduce the impact of weather conditions.
When sowing dry, without irrigation, false breaks or small rain events need to be considered with irrigation needed to continue growth or resowing may be required.
The average time for the break at Kyabram is April 25 (Anzac Day), meaning there is a 50/50 chance of a ‘true’ break occurring by this date, but the later we push into autumn, the better the chance a rainfall event will be a ‘true’ break.
Once there is a plan in place taking into consideration temperature and water, it is important to get the basics — sowing depth, good soil seed contact, nutrient management, pest control and grazing management — right to ensure the best establishment possible.
Depending on your approach to managing risk, you may decide to carry-over water for one to two irrigations to ensure spring growth.
■For more information on planning for the next season, phone Sarah Clack on 5824 5502 or email: [email protected]
■You can also phone Murray Dairy on 5833 5312 or go to: www.dairyaustralia.com.au for industry information on feed management and preparing for autumn.