Building a winter feed wedge provides feed for winter consumption, and avoids soil damage from over-grazing, and potentially reducing supplemental feeding.
- Long-term phosphate trials have shown its positive effect on winter production.
- 1 kg P/ha grew 1.7 t DM/ha.
- 15 kg P/ha grew 2.8 t DM/ha.
- Winter temperatures can cause pasture growth rates to drop to very low levels (0-15 kg DM/ha/day).
- Balance & Grow with nitrogen and gibberellic acid are “get out of jail” cards when short of winter feed.
The Winter Feed Gap
Generally, temperature has the greatest negative impact when growing winter pasture over the colder months.
Growth rates can drop to very low levels (0–15 kg DM/ha/day), and may be insufficient to meet stock demand. This is known as the winter-feed gap.
Winter Pasture Management strategy
- Keep pastures in the Phase II growth phase (capturing more sunlight/assists photosynthesis and regrowth.
- Increase winter active species.
- Consider reducing feed demand (stocking rates).
- Develop a feed wedge for winter feed.
Developing the Winter Feed Wedge
Building a feed-wedge refers to growing excess pasture during late summer/autumn, delivering a bank of feed for winter consumption.
This preserves feed on paddocks that may otherwise be grazed out, minimising soil damage and supplementary feed requirements.
Winter pasture growth can be significantly improved through improving soil fertility.
Phosphorus is a critical component of fertilie soils and adequate amounts can also improve applied nitrogen responses.
Fertilisers such as BioAgPhos provide sustained releaseÇ, enabling either annual or biennial (every second year) application.
Long-term phosphate trials have shown its positive effects on winter dry matter production:
- 1 kg P/ha grew 1.6 t DM/ha in winter (Olsen P 5 mg/kg)
- 15 kg P/year grew 2.8 t DM/ha in winter (Olsen P 13 mg/kg)
Growing winter pasture trials
BioAg have run a series of trials during winter incorporating Balance & Grow, nitrogen & gibberellic acid combinations.
These trials investigated the effects of these products on forage production, and how pasture quality (energy & protein) improved.
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Balance & Grow
Balance & Grow with nitrogen and gibberellic acid are get out of jail cards when caught short of winter feed.
This combination supplies the nitrogen required by pastures during winter, and supplies the plant’s requirements to convert nitrogen into true plant proteins (vitamins, minerals, proteins, amino acids, carbohydrates and plant hormones).
Balance & Grow is best applied to green leaf just after a grazing has finished and can be mixed with gibberellic acid and foliar nitrogen fertilisers in a single application.
Whilst BioAg programs are tailored to suit each grower, the basis of the program is Balance & Grow and UAN (UAN is interchangeable with calcium nitrate if calcium levels are low).
BioAg also produce a Balance & Grow Organic variant which is certified for use by organic growers.
Nitrogen (urea, sulphate of ammonia, Easy N (UAN), calcium nitrate)
Balance & Grow is compatible with foliar nitrogen fertilisers, so can be applied as a single application.
Nitrogen is best applied immediately after stock have been removed from the paddock.
Soil temperature, soil moisture, soil fertility and species composition all impact on the pasture responses to applied nitrogen.
In winter, a north facing slope can be 2ÆC warmer than a south facing slope.
Applying nitrogen to north facing slopes in July and south facing slopes in August (as temperatures begin to warm) can give a greater growth response than applying nitrogen to both areas at the same time.
If pasture is moisture stressed (too dry or too wet), the response to nitrogen will be restricted.
The greatest response to nitrogen fertiliser is seen in annual grasses, followed by short rotation grasses, then perennial grasses.
If other nutrients (e.g. phosphorus, potassium) are limiting growth, the response to nitrogen could also be reduced.
Gibberellic Acid (Pro Gibb, Gala, Ryz-Up)
Gibberellic acid is a naturally occurring plant hormone that stimulates growth through cell expansion.
In grasses, this results in stem and leaf elongation.
Its production naturally slows during colder months.
Applying gibberellic acid mixed with Balance & Grow in colder winter months stimulates the plant and can improve the quantity of feed on offer.
The rapid growth is often lighter (yellow) in colour for the first couple of weeks after application, which does not affect the quality of the feed on offer.
Growth stimulation is usually seen within seven days of application.
A BioAg Area Sales Agronomist can provide further details on its application, use with a rotational grazing program, frequency of use, expected responses from various pasture types, and optimal period of use.
Data from a cutting trial at Ellinbank indicated that responses to nitrogen are limited at soil phosphorus levels below 14 mg/kg Olsen P.
The Role of RPR Fertiliser in Aust. (Tas.) CSIRO Publishing, 1997.
Hamilton Long-Term Phosphate Experiment.
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