Now is time to clean off paddocks
Published 16/03/2010 | 05:00
Looking at grassland today is like going back 30 or 40 years when a lot of stock was out-wintered and fields were bare at this time of the year.
The period between mid-March and mid-April was known as the hungry gap when winter feed began to run out and spring grass was still not in plentiful supply.
We would expect to have growth of about 15kg DM/ha in March but so far it has been nil, apart from in the more climatically favoured areas. More significantly, the grass covers coming through the winter have been devastated by severe frost. Good ryegrass swards that were closed from late-October/early November have covers of 1,000-1,400kg DM/ha consisting of a mixture of green and decayed leaves in almost equal proportions. The feeding value of this material is still quite good.
Analysis indicates a digestibility of 70-80pc, depending on the ratio of green leaf to withered material, and the dry matter is up to 30pc as a result of the dry, easterly winds. Old pasture swards have very little cover and little sign of growth.
Current forecasts, at the time of writing, are that the weather will become unsettled, with temperatures hitting normal March levels. Increasing cloud will help reduce the incidence of frost, which will result in soil temperatures reaching normal values of 6-8°C.
Grass that has accumulated since last autumn should be grazed off. This will allow fresh growth to start that will respond to nitrogen.
Silage fields might have to be split up and block-grazed to get cattle to remove all the herbage. If given a choice they will selectively graze out the leafier material. While conditions are good, the heavier land could be grazed first. Unless you are short of feed, aim to close for silage in the first week of April. This will entail grazing off the silage ground by early April. The whole farm (silage and grazing areas) should have been grazed once by about the third week of April but this will vary depending on location and soil type. Achieving this target involves putting out the right amount of cattle in relation to the amount of grass available. A weekly grass budget will give a good guide to the appropriate stocking rate.