One of the best farm investments is renewing pastures according to Ballance Agri-Nutrients Forage Specialist Murray Lane. “By focusing on fertility, pasture weed and pest control, along with drainage and cultivar selection, you can expect leafier, more palatable pasture that is higher in metabolisable energy and grows more on the shoulders of the season.”
“Identify pastures for renewal early. A soil test about six months before sowing enables low pH to be addressed by liming. Low pH soils have more aluminium in the soil solution. Moderate aluminium is tolerated by browntop but is toxic to ryegrass roots affecting pasture longevity.”
By identifying the paddock early, perennial weed species requiring an autumn sprayout for optimum control can be identified, sprayed and sown into an annual ryegrass pasture for the winter.
In pastures, monitor the top 75 mm of the soil as most clover roots are in this zone. By having the fertility suitable for clover, it will be suitable for ryegrass. Ryegrass tolerates and grows in lower soil fertility than clovers but needs clover nitrogen (N). With good clover content, significant N is fixed, enabling ryegrass to compete against weed grasses.
When sowing new pasture, either directly grass to grass or following a crop, the paddock should ideally have a pH in the range of 5.8 to 6.2, Olsen P at 20+, MAF QT Potassium around 6 to 7, Quick Test magnesium at 10 to 12, and sulphur at 10 to 12. Other than liming, these nutrient levels can all be addressed with the application of an appropriate fertiliser nearer to sowing.
Once the pasture is established, keep the soil fertility at or above these readings.
To ensure good establishment, drill the seed with 150 kg of di-ammonium phosphate per ha in the slot with, or ideally adjacent to, the seed.
Germinating seeds benefit from phosphorus for early root and shoot development and N for tillering and leaf expansion. Di-ammonium phosphate (DAP) drilled next to the seed provides these nutrients, promoting canopy cover and inhibiting weed growth (as shown in the image). Broadcast 250 to 350 kg of DAP if drilling the fertiliser with seed is not possible.
Ideally, clovers are significant in new pasture in five to six months. By having a period in crop with no clovers, key clover pests such as nematodes decline, improving establishment. Be aware of any herbicide residues from the previous crop and follow plant back guidelines. Applying Sustain (N) at around 65 kg per ha (30 kg of N per ha) after each grazing in the first year encourages tillering, promotes a healthy sward and reduces weed competition. Clover likes it too, if the pasture is grazed frequently so clovers get plenty of light.
Your local PGG Wrightson Technical Field Representative can assist you with forming an effective fertiliser programme for your newly sown pasture.
