After assessing soil tests, establish which fertiliser is needed for that soil type. Generally, hard‑seeded legumes need at last 10kg of P/ha applied at sowing, with a similar rate of sulphur. If molybdenum deficiency is known, this should be rectified at sowing and treated every five years. Potassium deficiency can also be an issue on light sandy soils.
There should be a minimum of two or preferably three years of absolute weed control prior to sowing a pasture. This is usually achieved by a combination of cropping and herbicide use.
Check herbicide labels carefully to ensure herbicides to be used in the cropping clean-up phase do not have the potential to cause residual damage in the establishing pasture. In terms of weed control in the newly sown pasture, do not assume the new legume species are tolerant to herbicides used on traditional pasture species. Consult an agronomist for advice.
Some species such as biserrula are less palatable than some problematic cropping weeds such as annual ryegrass. Therefore, using biserrula may offer potential for control of ryegrass and some other weeds during the pasture phase.
The primary goal with any legume‑based pasture is to maximise seed set in the first year to ensure a large and resilient seed bank for long-term regeneration.
Generally, pastures sown in late autumn and early winter will not produce sufficient feed for grazing in the first year. In very dry years it is best to leave them ungrazed.
Managing the seed bank
Care is needed when grazing in the flowering period to avoid removing seed heads prior to seed formation, particularly in the establishment year. Arrowleaf clover can be particularly sensitive to overgrazing during reproductive growth stages due to its prominent seed heads. After the establishment year, good seed set should be supported every two to three years.
As these legumes produce high quantities of dry matter in spring, there can be dry residue available for summer grazing. Livestock can also be useful in spreading seed. The smaller the seed, the greater the proportion of seeds that survive ingestion with biserrula, gland and arrowleaf clover having a higher proportion of seed that escapes digestion, compared to bladder clover and French serradella.
Biserrula should be grazed to no less than 1,500kg DM/ha, arrowleaf clover to 2,000kg DM/ha and bladder clover to 1,700kg DM/ha to ensure adequate seed production. In seasons with poor growing conditions, forego grazing to ensure seed production.