Pasture establishment for higher yields
Planning ahead for pasture is a good way to improve yields. The keys to success are to plan in advance, understand your soil, manage weeds and pests and ensure your approach to sowing and fertilising are right for your selected seed.
Valley Seeds Area Manager David Phelps provides his top tips for planning ahead.
Fail to Plan and Plan to Fail
1. Select potential paddocks; assess and plan early – start at least 12–18 months before sowing
Talk to your Valley Seeds Representative about options and planning. You’ll also need to budget for the appropriate inputs – paddock preparation and sowing, herbicides, insecticides, seed and fertiliser.
Consider what livestock is run on the farm, what pasture is required and when is it needed. What you do with your paddock should vary for dairy, beef, sheep, annual or perennial, autumn, winter, spring or summer?
Is a current soil test result available? – this can provide vital information to assist in decision making. Are soil nutrient levels (fertility), the soil pH suitable for the proposed pasture? If not, reassess paddock selection, species, fertiliser, and need for lime or gypsum.
Weeds and insect pests
What weed and insect pests need to be controlled? Competition from annual grasses is the major cause of poor establishment. Some weeds may need to be controlled over several years prior to sowing a permanent pasture.
Are any herbicide residues present that could affect the species being sown?
How will the seed be sown? What sowing equipment will be used? – ensure equipment can place seed accurately to optimise the contact between seed and soil. Other options may include the broadcasting of seed or mulching into heavy thatch.
2. Weed and pest control in leading up to sowing
Consider all factors of weed and pest control including equipment, types of weeds and sowing depth.
Is the boom-spray calibrated and operating correctly? Do you have access to a reliable contractor?
Are broadleaf weeds a problem? – consider the spray-graze technique.
Are annual grass weeds a problem? Spray fallowing is preferred to spray topping because windy spring weather can prevent spraying at the correct time so that annuals still set enough seed to cause establishment failure during the following autumn.
What insect pests are present or likely to be present that may affect establishment? Strategic spraying in spring (Time-Rite), to reduce the adult population that produces over-summering eggs, is very effective in reducing red legged earth mite activity the following autumn but may not be as effective for blue oat mites. Insecticides may be added to the spray fallow or other herbicide applications provided the strategic timing of the insecticide is not compromised and is consistent with label directions. Other pests of seedling pastures such as cockchafers, lucerne flea, scarabs etc. will require different control measures.
Conventional sowings – use cultivation. Paddocks should be even, and have a fine, firm and moist seed bed in conjunction with herbicides.
Direct drill or surface sowings – graze leading up to the sowing period to keep pasture only 1–2 cm tall when using sheep or 3–4 cm tall with cattle.
3. Weed and pest control – the most important factor for success
Consider rainfall, weed and pest varieties and sowing methods to minimise the impact of weeds and pests.
As a rule, don’t sow on the first rain of the season (as subsequent weed germination is likely to be a problem).
Weed and pest types
Identify what weeds are present or likely to be present.
– either use the appropriate herbicide at label rates, or
– cultivate to achieve a firm, fine weed-free seedbed.
Identify what pests are present or likely to be present and apply the appropriate insecticide. For earth mites, spray 4 weeks after the autumn break. This often coincides with the knock-down herbicide application prior to sowing.
Where sowing into a dry seedbed is the only practical option (e.g. direct drilling cracking clay soils), good weed control in the previous season is paramount.
Preferably sow without cover crops – these compete with the young pasture for moisture and light just like weeds.
4. Adequate soil moisture – enough for quick germination and survival of the sown pasture
Choose when to sow and ensure your seedbed is prepared for the seeds you wish to sow.
Provide a firm, moist seedbed. This allows close contact between the soil and the seed. Seeds can then absorb moisture, germinate and emerge more quickly and reliably.
Choose sowing conditions
Sow when conditions are best for germination and survival
– temperate perennials: from autumn through to early spring (depending on the district)
– sub tropical species: sow late spring to early autumn.
Generally, avoid dry sowing as it increases the risk of failure. Where dry sowing has been successful, competition from weeds has been minimal and germinating rainfall has been enough for seedling survival until follow-up rain has fallen.
For temperate species which can be sown in the cooler months, adequate soil moisture is more important than time of sowing.
5. Accurate seed placement – neither exposed nor buried too deep
Seed placement will vary depending on the seed variety and quality. Other considerations for placement include soil nutrition and moisture.
- Direct drilling
Average furrow depth 25 mm, provided the furrow remains open, with 1–2 cm of loose soil over the seed.
Avoid using harrows or rollers. Press wheels should be OK
- Conventional sowing
Beware of sowing too deep especially when the seedbed is loose and fluffy.
Rolling (press wheels) can enhance seed-soil contact but beware of surface crusting in some soils.
- Use seed that is certified, or quality assured wherever possible and check its germination and purity.
- Use appropriate seed rates to ensure a dense pasture.
- Be aware of specific requirements of some species e.g. Rhodes grass, Teff grass, Lovegrass and Wallaby grass require very shallow sowing.
- Be aware that some soil types such as heavy cracking clays can lose moisture quickly after sowing while other clays are prone to surface crusting or frost lift in ploughed seedbeds.
- Ensure legume seed is inoculated with the correct strain of rhizobia and where necessary, lime pelleted. Molybdenum, insecticides and fungicides can be applied to seed to enhance establishment in many situations.
- Provide good nutrition – Apply adequate phosphorus, sulphur and molybdenum at sowing time.
- Use nitrogen fortified (compound) fertilisers for direct drill sowings (maximum rate, 20 kg N/ha). Banding fertiliser near the seed more efficient than broadcasting.
- Soil temperature can also be a consideration when soiling even if soil moisture is adequate – soil surface temperatures higher than 25 degrees Centigrade can be detrimental to ryegrass and some annual clover germination.
6. Monitor weeds and pests regularly after sowing
Catching pests and weeds early will help you manage them for the best result. Factors to consider include the sowing method and depth of seeds.
- Check pastures for pests regularly. For earth mites this may require close inspection on hands and knees. If you need glasses for reading, you’ll probably need glasses to see earth mites. Treat young pastures immediately if mites are found – many mites will probably not be seen.
- The likelihood of insect pests being present is generally greater in direct drilled than conventionally sown new pastures.
- Control weeds with selective herbicides or possibly with grazing in grassy situations.
- In direct drilled pastures under warm, moist spring conditions, slugs may be a problem. Slugs can be detected by placing wet paper under bags or boards at several sites. A registered insecticide is available for use at or after sowing if they pose a significant threat.
7. Initial and subsequent grazing
Manage how you graze the pasture to keep it producing for you. Choose which livestock to put onto the pasture and allow your pasture to rest and set seed.
- Once grasses are 10–15 cm tall and under good growing conditions, a quick grazing can help enhance tillering and root development. Graze heavily but quickly down to 2.5 cm then rest. Do the pull test (i.e. take a handful of pasture and tear up of the ground, if no roots come out then it is OK to graze). Never graze newly sown pastures early under dry conditions or if grasses are poorly developed.
- Lighter framed animals are best, and avoid grazing when the soil is wet.
- Consider an application of N-based fertiliser after the first grazing to promote a quicker recovery and to help encourage further tillering of the plants.
- Always allow grasses to set seed in the first year. Hay cutting for perennial pastures is not recommended in the first year.
- Avoid grazing aerial or surface sown (broadcast) pastures before they set seed. Their root systems are rarely well anchored and can easily be pulled out by stock. Do not over stock or over graze in the following growth season (e.g. autumn for temperate species, spring for sub-topical’s) as this will reduce life of the pasture.
- Some pastures have specific grazing requirements (e.g. lucerne and chicory require rotational grazing for good persistence).
- Recent research suggests perennial grasses will be more persistent when rested, especially under adverse conditions i.e. given some form of rotational grazing at least for part of the year.
- The most efficient grazing system for any farm will generally involve a combination of set stocking and some form of rotational grazing.
A summary of seven steps to follow for productive pasture…
- Analyse the paddock
Assess the existing pasture, soil fertility, weed and pest risk.
- Plan in advance
Reduce weed seed reserves in the soil and insect pests by using techniques such as spray-graze, spray fallow, pasture-topping, spring fodder crops and integrated pest management procedures. This step must commence in the previous spring for autumn/winter sowing to prevent annual weed seed set.
Manage the paddock for 3–4 months prior to sowing to reduce trash and maximise weed germination/control.
- Allow weeds to germinate and watch for bugs
Allow full weed germination after the break of the season or after irrigation. Either cultivate or graze to keep weeds small while waiting for optimum sowing conditions. Spray with a selective herbicide prior to sowing. Remember both red legged earth and blue oat mites hatch after the autumn break especially when maximum day temperatures are below 20°C. They start producing eggs 6–8 weeks later.
- Check moisture
Ideally moisture should extend from the surface to at least 20 cm.
- Sow to optimum depth
For direct drill sowings of most small seeded species, 5% of seed/fertiliser should still be visible in the row; for ploughed seedbeds, soil over the seed should be no more than 1 cm deep. When sowing cereals, seeds can be sown 3-5cm deep for better access to existing soil moisture.
- Check for pests and weeds
Look for pests and weed seedlings at 10–14 day intervals after sowing. This check is most often overlooked.
- Monitor before grazing
Check to see that grasses are 10-15cm tall and well anchored as well as there being adequate moisture.