Optimising Pasture Performance
The ‘big hits’ when it comes to pasture performance are soil fertility, grazing management and species selection. These three components are under your control and have the largest influence on the amount of stock you can carry.
Fertility
To measure soil fertility, a regular pattern of soil and plant testing should be undertaken. These tests should be on different soil types and between and within various paddocks. Similar sites monitored every three to four years. A soil test will give you a direct measure of the chemical properties of your soil. These results are then used to derive a recommendation to meet your production targets.
Soil fertility drives pasture mass not growth rates. This means that the plants will be growing at the same rate, but more fertile soils will be able to produce a greater mass which results in more feed for your stock or more hay. Increased fertility also has a direct correlation with desirable species. Poor fertility tends to favour undesirable species such as flatweed, silver grass and Guildford grass. Higher levels of fertility favour ryegrass, lucerne and clover.
Grazing Management
Research shows the benefits of rotationally grazing according to the physiological stage of the plant. Using rotational grazing provides many benefits including increased growth and utilisation, increased rooting depth, improved pasture composition and increased water and nutrient usage. If stocking pressure is too high the pasture will be overgrazed reducing subsequent growth. If the pasture is under grazed, plants will tend to senesce reducing utilisation by the animal and successive growth.
Ryegrass pastures should not be grazed for the first two weeks after the break of season to allow the pasture to ‘get away’. This increases root development and leaf area which encourages greater plant growth. A quick, light, first graze will promote increased tillering and plant density. After a light grazing a rotational system can be implemented based on the time taken for the plant to reach the 3-leaf stage. Set stocking can be used tactically on ‘sacrificial’ paddocks which have been used for deferred grazing at the start of the season. These paddocks can then be reseeded.
Species Selection
The variety of pasture species available in Australia is vast. Annual ryegrass, perennial ryegrass, sub-clover, lucerne forage crops and more. Then there are the varieties within each species. Your first priority should be to determine when the feed is required, and which pastures species will give you the best value. Then you can investigate which variety is most suitable.
Species should also be selected based on the quality the pasture gives you not just the quantity. The time of grazing and the fertilisers applied can all affect the quality of the pasture and the results these can have on livestock. Animal intake can work on an upward or downward spiral – they can eat more of a good quality feed, and less of a poor quality feed.
