Farm Ireland
Independent.ie

Tuesday 6 December 2016

High rainfall and better grass growth provide a silver lining

Dairy

Mary Kinston

Published 07/06/2011 | 05:00

Farming is a hands-on job, but sometimes it's more hands on than others. It's quite possible that you may have not even left the parish in the last month, never mind the county or country. This is especially the case when we are busy with mating and silage. And it's at times like this that we often fall into thinking that another farm's situation is similar to our own, especially when it comes to the weather.

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However, having visited the UK in the past week and doing my usual discussion groups and visits, the challenges facing each farm with regard to grassland management are being substantially influenced by rainfall and soil type.

For example, on our farm in north Kerry we've had plenty of rain, with 11mm in the past week and 41mm the week before. As a result grass growth has been good, ranging from 60-85kg DM/ha/day for the last month. Although a lot of the farm is a heavy clay, grazing conditions have in general been excellent, with the ground showing great soakage for the rain that we have received.

In contrast, a farmer I was talking to now finds himself grazing a field that was closed for silage because he is still experiencing rather dry conditions and his average pasture cover has dropped below 450kgDM/ha.

Britain has been suffering from even drier conditions. Some areas have received rain this week but grass growth is slow and supplementary feeding has been either a constant feature this year or been used heavily in the last month. Rainfall data for each of these examples is in the table (above).

Looking at the data, you would certainly be concerned about the high and rising cost of supplementary feed this year and the lack of winter forage in the UK situation, so at least Ireland has something to be thankful for, even if it's in the form of more rain and better grass growth.

If you face very dry conditions now or in the future, longer grazing rotations of 30-40 days will result in a speedier recovery once the rain is received. If you have to make the decision to graze off a silage field, then strip graze through this cover between morning and night milking. While this is a cheaper and better-quality option than resorting to silage, it will still be heavy going on your cows. You don't need to force them to eat it down to the usual residual of 3.5-5cm. Pre-mowing, topping afterwards or using drystock are all options to mop up any unused grass.

Alternate the feeding with a lower grazing cover of 1,200-1,500kgDM/ha if available so as not to penalise milk production and cow condition too heavily. It would be best to let the cows into this lighter cover at night time because they normally graze less during this period. Apply nitrogen fertiliser as soon as there has been significant rain at around 30-40kgN/ha (24-32units/ac). Nitrogen is important after a dry period as it helps to increase pasture cover but also encourages ryegrass to tiller.

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Whilst there has been variation in the growing conditions on many farms, one characteristic of the pasture that has been constant across the board is the earlier stem extension and appearance of the seed head of the perennial ryegrass. I reckon it to be approximately one month earlier than 2010. Other seed heads such as rough meadow grass, smooth meadow grass, Yorkshire fog and meadow foxtail have also become very obvious in pastures. As a result, pasture quality has been deteriorating and you may have used either pre-mowing or topping to correct this.

However, many farmers have experienced a slight reduction in grass growth recently and a concave hollow to the feed wedge. It is likely that the removal of the seed head has caused this as effectively a grass plants formation of a seed head is in fact a death sentence for these tillers because grazing or mowing removes their growing points.

Regrowth after the removal of the seed head comes from smaller vegetative tillers. Many of these would have been daughter tillers associated to the seed head which would have suppressed their growth and survival, so it's likely they were a bit slower growing. However pasture quality should be a little easier to maintain from here on in.

Mary Kinston is a farm consultant based in Kerry. Email: mary.kinston@gmail.com

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