Knowledge of the maturity group of your hay variety and how it responds to changes in sowing date can assist the planning of what variety to sow. Sowing them at appropriate times can spread the risk (so they are ready for cutting at staggered times).
The optimum stage for cutting hay is the watery ripe stage (Z71). At this stage, crushing a floret will squeeze out a watery solution. Some exporters may have different requirements for cutting time. Contact your exporter well before cutting time to determine their requirements.
In the event of rain occurring at the cutting stage, it is often better to delay cutting as the impact of rain on cut hay can often reduce hay quality more than a seven day delay in cutting date. The duration from sowing to reaching the watery ripe stage is modified by location, season, sowing date and variety.
- Twenty four oat varieties were grouped into six maturity groups (Table 1). Differences of over 30 days were noted in the duration to the watery ripe stage between the earliest variety (Yilgarn) and the latest variety (Massif).
- Most varieties responded the same way to changes in sowing date. Four varieties - Needilup, Possum , Swan and Winjardie – differed in their response to sowing date relative to other varieties in the same maturity class.
- A three week delay in sowing date results in only a 7 to 10 day difference in cutting date.
- Crops sown at Katanning take between 10 to 14 days longer to reach the watery ripe stage as crops sown on the same day at Northam.
- The information presented in this Farmnote are predicted dates based on actual trial data.
Background:
Like other cereals, the flowering date in oats responds to changes in day length and daily air temperature. For grain crops, the grain yield of a variety is often maximised by getting it to flower in the ‘flowering window’. This is done by matching the sowing date with the maturity of the variety in the region where the grain crop is being grown.
For hay crops it is important to know the duration between sowing and when the crop reaches the watery ripe stage (critical stage for cutting). At this stage, crushing the top floret will squeeze out a watery solution. If the solution is milky the crop has reached the milky ripe stage and is past the optimum cutting stage for hay quality.
Many growers may wonder when their hay crops will be ready for hay cutting, i.e. when the majority of florets will reach the critical watery ripe stage. This is particularly when they grow a new variety or they sow at dates they are not used to (such as in 2006).
It is important to know what maturity class the varieties are that you intend to sow and how they respond to sowing so you can better plan the hay cutting period.
This Farmnote outlines results from flowering date trials conducted at Northam and Katanning in the seasons of 2003, 2004 and 2005 and predicts the date at which 24 different varieties will reach the watery ripe stage according to seeding date and location.
Impact of variety on cutting date:
The duration to watery ripe was determined for 24 oat varieties. Table 1 groups these varieties into a range of maturity classes, based on their duration to watery ripe when sown in the period between late May to early June in the region between Northam and Katanning.
Groups are based on expected differences in maturity relative to Carrolup and are calculated from flowering date trials which were monitored three times per week. Large differences in duration to watery ripe were noted amongst oat varieties.
The difference between the earliest (Yilgarn) and latest (Massif) was over 30 days. Within the hay varieties Brusher generally reached the watery ripe stage first, followed by Marloo, Swan, Winjardie and Kangaroo and finally by Wintaroo .
Brusher was ready for cutting at a similar time to Carrolup. Wandering , another popular variety cut for hay, reached the watery ripe stage slightly earlier than Carrolup.
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