Compared with most grasses, white and red clovers are more difficult to establish and maintain. Extra care needs to be taken during pasture establishment to ensure adequate clover and content, and maintenance of this will be affected by grazing management.
Establishment in Pastures
- White and red clovers compete poorly with grasses and weeds during the establishment year, and are sensitive to deep sowing, cold soils, and drought.
- A thorough preparation of the paddock is needed before sowing. Remove as many weeds and their seeds, through combinations of spraying, cultivation, and cropping.
- If cultivating, a fine and firm seedbed is needed to allow for shallow seed depth and good soil to seed contact. Seed should be sown at a depth of 10-15mm of firm soil, with rolling often required pre and post sowing.
- When direct-drilling, extra care is needed to achieve the shallow seed depth, and coverage of the seed with firm soil.
- Take a soil test and if pH or nutrient levels are low, apply extra amounts of lime or fertilizer one to six months before planting to correct deficiencies. These clovers require pH levels in water of 5.6 to 6.5 to perform and persist well.
- White clover should be planted at 1-4kg/ha, and red clover at 4-6 kg/ha. If clover seed is coated, increase sowing rate to allow for the weight of the coating. Inoculation is required if the soil has not had clover growing recently. The inoculum needs to be fresh. Insecticide seed treatment can be important, especially with insects such as ants and earth mites.
- Clover establishment can be poor if soils are cold at sowing, or 2-3 months afterwards. Ideally soils should be above 10°C. Drought and high temperatures in the first 2-3 months will also restrict clover establishment.
- Do not use residual herbicides on previous crops that could affect germination of clover within the plant-back period on the chemical label.
- Insect and weed control is critical in the first year. Monitor from the first week of sowing, and control insects early. Weeds should be sprayed when still young, as soon as the clover plants have two trifoliate leaves (longer for some herbicides). Use herbicides that are registered for white or red clover.
- Competition with weeds and grass in the first winter is a major reason for poor clover establishment. Ryegrass is a common companion, but competes strongly for light and soil moisture. The grass should be grazed before it exceeds 8-10cm, with short grazing-durations. Avoid grazing when the soils are excessively wet or dry.
White clover is a perennial plant that spreads with stems attached to the soil (called stolon’s), which grow and form new roots and plants. This is its main mechanism for survival, and it does not need to set seed. Stolon growth and spread is maximized when soil temperatures are mild to warm (spring), soils are moist and fertile, and plenty of sunlight reaches the soil surface. Stolon’s shrink during dry and hot summers, but can then grow back after autumn breaks, when clover pastures should be managed like establishing pastures.
Red clover does not have stolon’s but has a deeper and longer-lived tap root. When plants are damaged (over-grazing, pugging, root disease), they cannot re-populate the pasture like white clover.
Once established, these clovers do best under rotational grazing, with grazing durations of 1-2 days and spells of 20-30 days. Keep the grass below 12cm, because most of the clover plant lives close to the ground and cannot compete for light with high grass covers. The clovers are preferentially grazed to low levels, so set-stocking leads to over grazing of clover and eventual dominance of grasses.
White and red clovers are shallow-rooted and have less drought tolerance than most grasses. During dry periods, it is important to spell clover – based pastures until there is enough rain to ensure strong recovery of grazed plants.
Soil nutrients (P, K, S and Mo) and pH need to be maintained at good levels for these clovers to compete with grasses. High use of nitrogen (200 kg N/ha/yr.) can reduce clover content.
With the spread of Clover Root Weevil, clover management is becoming more important to give clovers more potential of contributing to the farm system.