As with any other crop, getting the pH right for grass and clovers is vital with the optimum pH for most grasses around pH 6.0 and for red and white clovers a little higher at 6.5.
If your soils are acidic then lime should be applied to make it more alkaline.
Lime comes in various forms and the choice of type has an effect on the speed at which the pH is changed, although most types takes some months to have an effect. The fastest result can be achieved by applying Granulated Lime. This is a fine, powdery material with a small particle size which acts fast when applied. Larger particle size leads to less effect and needs to be applied at a higher application rate to do the same job.
Applications applied to the soil surface will stay in the top few centimetres where it will be beneficial for shallow rooted cops such as ryegrass. For deeper rooting plants, such as red clover, lime applications should be ploughed in well in advance.
Eventually, and particularly with the application of acidic ammonium nitrate fertilisers, most soils will revert back to their natural state so the pH must be monitored regularly.