Management Notes for April 2018

Date published: 5 April 2018

DAIRYING

Prepared by: Christopher Breen

Cows at grass

Last month I encouraged you to get your cows out. Now that the time has changed your cows should be going to grass straight after morning milking and grazing for half a day. A ‘crash’ in milk yield is a concern when turning cows out to grass. So how can you maximise daily yield and remain feed efficient on your farm this spring, when the yield of individual cows can vary from 15 to 60 litres?

In a spread calving pattern herd, batching your cows into yield groups will help. Use milk yields to sort cows into groups for:

• Grazing full-time - lowest yielding/late lactation cows
• Grazing by day and housed at night - mid lactation cows
• Housed full-time - fresh calved/highest yielding cows

For the grazing group the ration M+ will depend on the grass supply and quality. For the partial grazing or full-time housed groups the ration M+ should be formulated so that the lowest yielding cow in the group is not overfed. The M+ will change as cows are moved from housing, through partial grazing to full-time grazing.

Farmers with cows grazing for a few hours after morning milking are topping them up in the parlour after their first 10 litres of milk at a rate of 0.45 kg of concentrate per litre. Once cows are settled on daytime grazing, restrict parlour feeding only to cows giving more than 15 litres. When full-time grazing a cow yielding 40 litres per day requires 7.5 kg of concentrate. Cows yielding more than 40 litres should still be allowed access to blend in the TMR. Aim to have your grazing rotation fully established by the third week in April. Full-time grazing will then provide the nutritional requirement for cows yielding up to 22 - 25 litres but this will depend on both weather and grazing conditions. The table below shows a practical spring transition. This can be fine-tuned based on the daily milk sales and concentrate levels fed.

Relieving soil compaction

Many fields suffered from soil compaction in 2017 due to wet ground conditions. Where soil is dry enough to fracture now is a good time to relieve problems caused by compaction. In affected fields dig test holes half the length of a spade to find the depth of the compacted layer. Signs of compaction include a layer that is hard to break up, shallow roots growing horizontally, few worms, bad smell or grey colour and brown mottling. The depth of the compacted layer determines the type of machine that should be used to correct the problem. Use a machine that reaches deep enough to lift and loosen the compacted layer when the soil is dry enough to fracture.

Nitrogen for silage

A splash-plate application of 33 cubic metres per hectare (3,000 gallons per acre) of cow slurry this February or March will have supplied enough phosphate and potash for first cut silage at typical silage field soil indices. It will also have provided some nitrogen for grass growth but there is still a major requirement for nitrogen fertiliser. You should now apply up to 100 kg of nitrogen per hectare (80 units per acre) to fields for first cut.

April jobs checklist

• Prepare for the forthcoming breeding season. How good are your heat detection rates? Can these be improved? Have you selected suitable bulls to achieve your long term breeding goals?
• Assess condition of young stock, especially maiden heifers. Will they be in the right condition for service?
• If not already done so, change your time clocks now that the hour has changed!

BEEF AND SHEEP

Prepared by: Nigel Gould

BEEF

Turnout to grass

Turn cattle out to grass as weather and grass covers allow. Prioritise young stock and cows with calves at foot. On farms with ‘heavier’ ground, turnout young, light stock as this will allow you to start to empty sheds while minimising poaching. In some situations, if not already started, it may be possible to creep graze older calves first, allowing them access to grazing close to the shed, while cows are turned out at a later date. For autumn born calves this can act as a ‘gradual weaning’ process, reducing the maternal bond and reducing stress on these calves at weaning. Ideally, before turn out, give cattle access to an open yard and restrict feed for a few hours. This encourages them to start grazing immediately at turnout and reduces the incidence of poaching. Turning stock out in the morning allows them to adjust body temperature to adapt to cooler night temperatures. Use sheltered paddocks or fields for more vulnerable stock such as calves and weanlings. Start the grazing season at a low stocking rate, without allowing cattle to roam large areas. Continue to graze smaller areas and move on. Monitor grass closely, getting management right now will impact on the rest of the grazing season. Indeed, for a successful grazing season, planning should have started last autumn with timely closing of paddocks. Fertiliser and slurry, if not yet applied should be spread according to soil analysis.

Paddock grazing

In general, rotational grazing when compared with set stocking has the potential to improve grass quality and utilisation. When dividing ground into paddocks, ideally they should be square in shape as opposed to long and narrow. The former has been shown to reduce poaching in poorer weather when stock tend to stay close to the boundaries. It is important to graze paddocks out well in the first rotation. Opening covers of 2000-2500 kg dry matter (DM) per hectare for the first grazing in early spring are acceptable, with smaller animals targeted towards the lower covers. Later in the season, closer to peak grass growth, follow the ‘rule of threes’, that is 3000 kg DM per hectare of an opening cover, grazed for three days and return to graze in three weeks.

Closing for silage

If grazing silage ground, do so first but have it closed by mid-April at the latest. Grazing later will push back the silage harvesting date and increase the amount of heading in the crop, which will directly reduce D-Value and overall silage quality. Grazing before then is beneficial as it removes dead material from the sward, which will be more of a problem where poor weather impacted on grazing last autumn. When closed, apply fertiliser and slurry based on soil analysis results. For example, land with optimum indices of 2+ and 2- for phosphorus (P) and potassium (K), apply up to 120, 40 and 80 kg per hectare of nitrogen, P and K respectively (in addition to 35-40 kg per hectare of sulphur). If you are more familiar with units per acre multiply by 0.8 to convert from kg per hectare to units per acre.

Preventing Grass Tetany

Grass Tetany (Hypomagnesaemia) can be an issue in early spring when rapidly growing, lush grass with a quick passage rate through the animal can lead to magnesium deficiency. Higher producing animals, such as lactating cows and ewes, are most at risk, especially in periods of wet weather. It can be made worse by high levels of potassium in grass, for example from fertiliser which can interfere with the absorption of magnesium in the animal. Magnesium isn’t stored in the body therefore it must be consumed in the daily diet. High magnesium lick buckets are the most common way of preventing Grass Tetany.

SHEEP

Lambing

Lambing, although possibly just beginning in hill flocks, will be well underway for most farms. Be aware of the high nutritional demands of a ewe rearing twin lambs. If grass is scarce, supplement with concentrate until grass growth improves. Maximising milk production in the ewe is important in driving lamb growth rates, especially for the first six weeks, when milk forms the majority of the diet. If the flock is in a programme of clostridial vaccination, lambs will need to enter this programme after six to eight weeks of age.

Note: April-July (assumes annual application of 150 kg N/hectare)

CROPS

Prepared by: Leigh McClean

WINTER CEREALS

Despite the prolonged winter weather through most of March, winter cereals are still due their second dose of nitrogen at early stem extension (growth stage 30-32), barley normally reaching this stage ahead of wheat. Top up sulphur at this dressing to give a total rate of 25-40 kg per hectare of SO3 for all cereals.

Inspect crops for any recently emerged broad leaved weeds applying top up herbicide as soon as conditions allow. As with all pesticides adhere to product labels, paying particular attention to latest application timings, sequences with other herbicides and approved tank mixes with other products.

Watch out for frost heave, where plants are physically lifted out of the ground caused by recent freezing temperatures, particularly on later drilled crops. To remedy this, a pass with Cambridge rolls can help firm soil in the rooting zone once soil has dried sufficiently to travel, though be careful not to roll in frosty conditions as this may kill the plants completely. In addition, an early application of plant growth regulator, for example Chlormequat or Moddus, will encourage plants to root and reduce the risk of root lodging later in the season.

Disease control

In recent years mild, good growing winters tended to produce thick crops which have had some level of foliar disease at this time of year. Even after a cold, wet and long winter which has resulted in thinner, less leafy crops this does not necessarily mean the foliar disease threat is reduced. Plants will undoubtedly have been under more stress this winter and as a result may be more susceptible to disease than strong healthy crops. Mildew and Rhynchosporium are the main early threats to winter barley and a good fungicide programme should not be overlooked. Where infection is severe keep fungicide rates high particularly where T0 fungicide was not applied or T1 has still to be applied. Apply the follow up T2 fungicide around growth stage 39 when the flag leaf has fully emerged and the first few awns are appearing, no later than four weeks from the T1 timing. At both T1 and T2 timings best performance comes with an SDHI or prothioconazole in the product mix. Strobilurins and other azoles actives aren’t as strong but still offer useful protection in mixes where crops are clean or disease pressure is lower.

Septoria will be the main threat to winter wheat and to a lesser extent mildew, particularly on susceptible varieties. Where T0 fungicide has not been applied the T1 will be critical to get on top of Septoria and should be applied around growth stage 32 ideally when leaf three is emerging. For the T1 use robust rates of Triazole mixed with an SDHI and multisite protectant.

SPRING BARLEY

Sow as soon as a good seedbed can be created, aiming for a seed rate between 350 and 400 grains per square metre. Also plan to treat weeds in emerging crops as soon as possible. Using pre-emergence herbicides can help manage resistant broad leaved weeds such as chickweed and also target problem annual meadow grass.

POTATOES

Sprouting and chitting

With pre-sprouting systems (bag or tray) ensure adequate temperature, ventilation and light to control sprout growth and protect against frost. As seed planted now will be for the main crop ensure the pre-sprouting system encourages multiple sprouting to produce many tubers which can increase in size over a longer growing season than with early varieties.

Greening and EFA requirements

Greening represents approximately 30% of your entitlement value so act early to make sure you meet your requirement.Crop diversification remains the same as in previous years, the two and three crop rules still apply. Those of you with Ecological Focus Area (EFA) requirement must still ensure an area equivalent to at least 5% of your arable land is used as an EFA.

HORTICULTURE

Prepared by: Kieran Lavelle

Ornamental plant production

News reports in recent years have mentioned a number of different plant pathogens which pose significant new threats to United Kingdom and Irish horticultural production, or even to the wider landscape and environment. One newly identified threat is a bacterial infection called Xylella fastidiosa. You are likely to see increasing media coverage about this disease throughout 2018 as it can cause serious symptoms across a wide range of plants.

Signs of Xylella infection may be mistaken for severe moisture deficit. They include scorching of leaves, leaf wilt or stem shrivel and sometimes even rapid limb death on affected trees. Xylella has already killed whole olive trees in Italy as well as infecting Prunus (cherry and almond) trees in Spain. For these reasons, plant health emergency measures have been agreed across the European Union, to minimise the spread of Xylella and to try and prevent its entry into any new member states.

The immediate consideration for all Northern Ireland (NI) growers and plant retailers is to ensure that up-to-date plant passports accompany any consignment of plants from those species classed as susceptible to Xylella fastidiosa. Currently this list of possible host plants runs to more than sixty species, with this number likely to increase. Within this list, there are also six ‘high risk’ plant species, named as olive (Olea europea), lavender (Lavandula dentata), almond (Prunus dulcis), Polygala (P. myrtifolia), oleander (Nerium oleander) and coffee (Coffea spp.). Any local premises producing these plants must be inspected more frequently and their plant produce sampled to ensure continued freedom from Xylella fastidiosa infected material.

Much more information about this bacterium, its implications for NI horticulture and links to various updates can be found via the ‘Plant and Tree Health’ pages of the DAERA website.

Powdery Mildew control in strawberries

Fresh, locally produced strawberries are a much loved and anticipated taste of summertime in NI. Local berries can be picked at a more ripe stage than those imported from Europe. This means the sugars within the berries are allowed to develop further and can lead to a sweeter, juicier berry.

Getting the berries to just the right stage for harvest takes a great deal of management. Most of the strawberry production in NI takes place in protected environments such as fixed poly tunnels or open sided Spanish tunnels. However, the often damp and humid conditions in the spring and summer can lead to a number of fungal disease issues for growers to manage, including Powdery Mildew.

Signs of Powdery Mildew on strawberries include:

• Cupped, curled leaves
• Powdery, white fungal growth on the underside of leaves
• Red-brown spots/lesions on the upper side of leaves (caused by the fungus on the underside, which kills plant tissue)
• Powdery, white fungal growth on the surface of fruit

While it is important to know the identification characteristics, seeing the problem on a strawberry crop is nearly too late. Changes to fungicide regulations mean that the only approved products are preventative treatments rather than curative. With this in mind, it is crucial you put in place a spray programme early in the season. This may include biological controls as well as conventional preventative sprays. For more information, contact Lori Hartman: lori.hartman@daera-ni.gov.uk.