A dilemma facing many small farmers is whether to renew an existing pasture and if the high replacement costs are worthwhile. 

There are both financial and other benefits in renewing a pasture, including increases in livestock production/health, improved ground cover/weed control and increases in soil carbon. 

Renewing pastures and increasing stocking rates are a good way for those farming small areas to increase farm income and help cover increasing fixed farm costs (e.g. rates, insurance, licenses). 

Pasture renewal can result in higher levels of production and income off the same land area. In most situations, this is more cost effective than buying extra land. To achieve any additional income from renewing a pasture, stocking rates and pasture utilisation need to be increased.

To renew or not?
Before you start, check your state vegetation act to ensure you are legally allowed to remove the existing pasture. 
The best way to know if a pasture is old and needs replacing is by looking at your livestock. Your livestock are a true reflection of the pasture they are eating. Successful livestock production is often described as 50% genetics and 50% nutrition. 

If your pasture lacks growth (even during a good season), has a low legume percentage (less than 20%), high weed populations or is generally performing below expectations, it is common for your livestock to show similar signs of tiredness, hollowness and poor production. These symptoms are an important sign that it is time to replace your pasture. 

The best place to start on your farm is where you are going to get the best ‘bang for your buck’. This can be determined by choosing the paddock with the most potential, one with the best aspect (easterly), soil type and fertility levels.

The decision to replace an existing pasture will also be influenced by the livestock being run. If your aim is to run a few breeding cows to help provide some supplementary income, there will be less need to replace the existing pasture compared to someone who finishes cattle/lambs and relies on the farm for their sole or partial income. 

There are also a number of other less costly management activities that can be undertaken to improve existing pastures without removing them completely. These will be discussed in Part 2: Improving existing pasture.

Pasture establishment methods
The most successful way to establish a new pasture is by removing the old one. This can be done through a variety of methods, including cultivation, slashing, burning or spraying.

New pastures are successfully established where weeds and other competing plants have been removed, where moisture has been stored, and where soil testing has been conducted with any deficiencies corrected. 

Any number of methods can be used to sow a new pasture, including over sowing, broadcasting, sod seeding and direct drilling. Direct drilling is often the preferred establishment technique, as it causes only minimal soil movement (eliminating risk of erosion) and allows accurate seed placement. Regardless of the sowing technique used, the most crucial step in the pasture renewal process is to plan well ahead and ensure that the paddock has adequate preparation.

Example pasture renewal program checklist and timeline
In this example, herbicides are used to remove weeds and direct drilling is used to establish the pasture.

• (Sep-Dec year prior) Spray out existing pasture to ensure annual weeds do not set seed. This can be done using a knockdown or contact herbicide. The period between spraying and planting is known as the fallow period where plant competition is reduced and soil moisture is conserved for planting.
• (Jan-Mar) Soil test, apply lime, gypsum and fertiliser as required. Spray out weeds using a knockdown herbicide prior to sowing.
• (Mar-May) Direct drill an annual crop, e.g. oats or ryegrass. Apply starter fertiliser (nitrogen, phosphorus, sulphur) at sowing.
• (May-July) Monitor crop for insects such as earth mite and spray out unwanted broadleaf weed species with a selective herbicide.
• (May-Dec) Graze crop until it has finished growing. The paddock may require another weed spray in spring/summer if high levels of weeds are still present.
• (Feb-May subsequent year) Spray paddock out with a knockdown herbicide to remove any weeds. Direct drill pasture seed with starter fertiliser.

In summary
Renewing an existing pasture on your small property is a costly exercise and can range from $300-$800+/ha depending on the type of pasture sown and establishment technique used. To ensure you get a return on this investment, planning/preparation is essential and those who wake up today and decide to sow tomorrow are often bitterly disappointed. If you are considering farm expansion, increasing the number of livestock that can be run on the farm by improving the pasture is much cheaper than purchasing additional land.

Part 2: Enhancing your existing pasture
In part 2 of this series, we will discuss the alternative methods to improve your existing pasture without the expense of removing it completely.

Where to from here?
For further information on pasture development, purchase a copy of AgGuide - Pastures in a farming system.

Over-sowing: Sowing seed into existing pasture using narrow tines or discs, reducing soil disturbance.
Direct drilling: Sowing seed into a seed bed which has not been cultivated, after the application of herbicide.
Sod-Seeding: Sowing seed into an existing pasture once it has been slashed or mulched. Seed is broadcast or scratched into the soil surface.
Seed to soil contact: The level of contact that the seed has with the soil. The higher the levels of seed to soil contact the better the pasture establishment.
Purity: Percentage of the seed sample which is pure seed, showing weed seeds and other components.
Germination: Amount of seed which germinates after 14 days, represented as a percentage.
Agistment: Grazing livestock on another farm, other than your own for an agreed price, usually per head, per week.

Acknowledgement: Image is courtesy of Premium Property Care