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The drought can be considered "broken" only when there has been enough rain to take the soil to within about 15% of field capacity. That generally means more than 50mm. |
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Slow the rotation
This will allow the grass to get away and develop some root mass.
Feed more supplement
Up to half the grass available is lost after rain because it is dead and decays quickly, so cows will require the major part of their intake from supplement. You will need around 100kg DM per cow (up to 160kg on very dry farms) to feed the herd for about three weeks after rain. The DM content of new grass is low (below 15%) because of its rapid growth, so supplement will still be needed even when there is plenty of fresh feed available.
Apply N fertiliser
Nitrogen applications can be delayed for several weeks after rain as the soil will have good N reserves. The response to autumn applied N takes place over three months, so take this into account when making the final drying off decision.
Beware of nitrate poisoning
Soil nitrogen levels usually rise during a drought, and when rain arrives the new growth combined with cool, cloudy weather can cause nitrates to accumulate in leaves. This can lead to nitrate poisoning. Permanent pastures are generally safe in warm, sunny conditions but there is some risk in cool, cloudy weather. Any new grass and annuals sown after a drought could be toxic, and applying fertiliser N will increase the risk.
Reduce risk by:
- Testing suspect pastures with a nitrate kit from your vet
- Using long rotations
- Feeding cows other forages first - don't put hungry cows onto high risk pasture.
Refer to the following Farmfacts:
- Farmfact: Nitrogen - principles of applying nitrogen fertiliser to pasture (7-1)
- Farmfact: Nitrogen fertilisers (7-2)
Plan pasture restoration
The burnt-off patches in pastures will inevitably be filled by hardy but low feed-value grasses, and weeds. Availability of finance may limit the amount of renovation you can afford, so plan carefully.
Assess and prioritise pastures
- Paddock by paddock, assess how badly your pastures are affected and how likely they are to recover. How dense and strong are the grasses that are left? Have weeds taken over? Can they be repaired or renovated, or must they be replaced?
- After the drought breaks use the 50% rule - test the pasture by doing a minimum of 20 observations in front of where you place your right boot. Are there live ryegrass tillers present at the front of your boot? If the answer is no in more than 50% of cases, the paddock definitely requires renovation.
- What types of ryegrass and which endophytes have survived best?
- Taking into account the degree of damage and the productive potential of each paddock, rank them in order of priority (e.g. badly damaged pasture on productive flats will have a high priority).
Develop detailed actions for each paddock
- For partially damaged pasture (or where repair is not possible), make sure they have enough N for grasses and P, K and S for clovers. Consider extra fertiliser in early spring to boost growth. Use rotational grazing to allow plants to spread and replace root reserves
- For the rest, decide what crop or pasture species and varieties to sow in them and when, what fertiliser is needed, and the costs involved
- Use treated seeds to limit insect attack and enhance germination
- Undersowing or direct drilling with short-term ryegrass may boost feed supply early
- Involve family and staff in the planning process and seek advice from advisers and seed specialists with good pasture and crop experience.
Options for repairing drought-damaged pasture:
| State of damaged pasture: | Suitable options: |
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1. Mostly bare ground with no weeds present. |
Undersow with Italian ryegrass, or perennial ryegrass/clover |
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2. Mostly bare ground with some weeds likely to re-establish. |
Spray and direct-drill with short-term or perennial pasture |
| 3. Most productive plants have been
replaced by weeds. |
Spray/cultivate and plant 1-2 crops or short-term pasture before planting perennial pasture |
Options for spring-planted crops:
| Crop category: | Options: | Suitability: |
| Summer greenfeed (grazing) |
Rape, forage brassica,
turnips |
Rape and forage brassicas provide multiple grazing, and turnips a larger single grazing. |
| Winter greenfeed (grazing) |
Kale, Swedes, (or turnips planted in
summer) |
Swedes are suited to cooler regions, kale and swedes are popular for contract winter grazing. |
| Conserved feed (silage/hay) |
Triticale, barley, Italian ryegrass,
maize, lucerne |
Maize silage suits warm districts, triticale can be planted early-spring and barley mid-spring for whole crop silage, Italian ryegrass can provide multiple cuts. |
| Grain crops (cash crop) |
Barley, wheat,
triticale |
Require some skill to achieve reliable yields. |
Choose perennials that suit your farm
A perennial pasture can be sown after crop harvest in spring or autumn. Consider drought-tolerant alternatives to ryegrass - tall fescue is the most similar to ryegrass for growth and quality, and other options include cocksfoot, pasture brome, lucerne, chicory, plantain, and sub-clover. If you are sowing ryegrass and clover pastures, use the types of ryegrass and endophyte that have survived best during the drought as a guide for what will be most sustainable on your farm.
Remember young stock
Young stock are very sensitive to the stress of dry weather and special attention is required to keep them healthy and in good condition. Young stock should be monitored regularly, especially if grazed on run-off. Prompt veterinary attention should be obtained if young stock show signs of ill health or stress.
