While numerous studies have shown that sowing introduced pastures can be profitable, the exercise is highly sensitive to factors such as: how successful the establishment is, the life of the pasture, the potential increase in stocking rate or livestock production per hectare, the gross margin of the enterprise and the cost of purchasing extra stock to eat the extra feed. A worked example of the factors to include in a decision to increase pasture production and animal output, is given in MMFS Module 1 Plan for Success.
Different land classes and production systems (e.g. permanent pasture versus pastures in rotation with cropping) require different species mixtures. A practical way of combining soil and paddock information is presented in MMFS Module 6 Healthy Soils. Use the Guide to classifying land capability tool to assess the most appropriate pasture system for each area of the farm.
If there is a reasonable base of desirable species present, it is always less expensive and easier to use the grazing management practices outlined in Topic 2 to strengthen existing pastures, rather than sowing a new pasture.
The aim of this topic is to help sheep producers establish a new pasture in paddocks where there are insufficient desirable species present. This will require greater intervention.
While some clovers or medics and desirable annual grasses (e.g. annual ryegrass) can volunteer in pastures in many regions if conditions are right. They are unlikely to be as productive as sowing a pasture mix well suited to the soil and rainfall conditions.
Introducing new species and cultivars can involve a large capital expenditure, typically $200 – $400/ha, depending on sowing method and inputs required. The main reason for poor establishment of new pastures is lack of prior weed control, insect attack (e.g. slugs), poor seed depth control or poor timeliness of operations. Sowing new pastures is often done infrequently and conditions at sowing are never the same from one year to the next so it’s important to have a plan to reduce establishment failure. It can also be a risky exercise, particularly in regions where introduced perennial grasses, and even annual legumes, struggle to persist due to harsh or highly variable climatic conditions or soil.
The focus in this topic is on establishing and managing permanent pastures. There are many different issues to be considered in selecting, establishing and managing pastures in cropping rotations, such as control of pests, diseases and herbicide resistant weeds or nitrogen fixation for following crops. These factors often influence pasture selection and management more than the potential for animal production.
The first step is to assess the pasture to determine if the existing species are limiting pasture growth and quality.
- Identify desirable perennial grass plants. If there are some perennial grasses present, their size, vigour, density and growth rates might be able to be improved sufficiently to negate the need to sow more plants. As a rule of thumb, if there are 5–10 phalaris, cocksfoot or fescue plants per m2 or 10–15 perennial ryegrass plants per m2, there is an opportunity to use grazing to improve the perennial content of the pasture.
- Similar benchmarks likely apply to native perennial grasses but there is no way to economically re-sow these pastures (due to the historically slow and poor germination rate of native pastures) and therefore grazing management is the only option.
Note: Replacing native species with introduced pastures is restricted by native vegetation protection legislation in some regions. Check with the regional natural resource management authority (see signposts in MMFS Module 5 Protect Your Farm’s Natural Assets) before attempting to replace native pastures.
When sowing new pastures, the following three steps are critical to ensure the investment is profitable.
Ensure establishment succeeds the first time
Prepare for sowing at least 1–2 years before the proposed sowing date by starting weed control to reduce seed burden. This is critical to success and can involve numerous operations for weed clean-up. Identification and an understanding of lifecycle and seed longevity of problem weeds is important for planning. Annual weeds with short seed dormancy (seed survives for less than three years, such as, capeweed, barley grass) are easier controlled than perennial weeds with extensive root systems (e.g. bent grass, sorrel) or weeds with bulbs (e.g. onion grass, oxalis).
Commonly used weed clean-up strategies include spray grazing, winter cleaning, spray topping, selective herbicides or use of summer fodder crops. Cropping can provide more additional herbicide and weed control options.
Consider building soil fertility and applying lime application during the preparation phase.
Choose species and cultivars well suited to the land class and soil conditions and the rainfall pattern and reliability (i.e. tried and proven in the local area). The ‘right plant for the right place’ mantra applies and allows selection of species to match environmental conditions and suitable to the stresses likely to be encountered (e.g. drought, waterlogging or acidity). Consult with local advisors and use the MLA Pasture Trial Network (PTN) variety selection tool to search for local variety testing. There is a wealth of information on this topic. Sources relevant to different states and regions are listed in MMFS Module 7 Grow More Pasture.
Direct drilling (spray and sow) is a proven, reliable technique for establishing pastures for all regions, but is especially suitable in the high-rainfall–permanent pasture zone. In the sheep–wheat zone, undersowing can lower the cost, although competition from the crop usually results in poor establishment of less vigorous pasture species and is therefore not recommended. Refer to MMFS Module 7 Grow More Pasture for more information on pasture establishment methods.
Ensure the desirable species persist
The longer a pasture lasts, the more likely it is to be profitable. For long-term perennial pastures, strategic use of fertilisers and appropriate grazing management can help pastures persist almost indefinitely in the high rainfall zone (above 600 mm of annual rainfall). Different rules and expectations apply to short-term pastures sown in rotation with crops, but the benefits in livestock production and grain yields still have to outweigh the costs.
Short-term or special-purpose pastures (e.g., cereals, brassica, chicory, plantain or legumes) have a role in filling specific feed gaps but also as a way to clean up weeds prior to resowing a new perennial pasture. The short-term nature of many of these pastures means that substantial increases in livestock production per hectare (higher stocking rate or heavier lamb turn-off weights or savings in supplementary feed) are required to make sowing the pasture profitable.
Increase livestock production
Pasture introduction cannot increase returns by itself – the value comes from turning off more wool or meat per hectare or increasing the value of the product. In many cases, the investment in the extra animals needed to utilise the increase in pasture will be greater than the investment in the pasture itself. An additional investment in improved management skills may also help ensure a strong profit flow from an investment in pasture establishment.
Feed supply can be varied to meet animal demand by introducing new pasture species at critical times, increasing pasture growth as described in this module, or through better alignment of animal demand with pasture supply (see Topic 3 in MMFS Module 8 Turn Pasture into Product).