Everyones’ minds should be turning to applying fertiliser

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The pleasant weather over the last week has got most of us thinking about fertiliser and spray applications.

Crops have begun looking for nitrogen and as daylight hours are longer it is essential to apply fertiliser onto crops to maintain healthy foliage.

Who knows what the next few weeks have in store for us so it has been my advice to get on as soon as possible with fertiliser. The amounts of P&K at the target index 2 must be maintained and it is important to take into consideration the offtake in yield of grain when planning fertiliser applications.

As most of our straw is removed an NPK fertiliser should be applied in accordance with the RB209 taking into consideration the use of organic manures. Cereals are becoming more responsive to sulphur as atmospheric deposition of sulphur declines. Where deficiency has been recognised or is expected 25-50kgSO3/ha as a sulphate should be applied in early spring before the start of stem extension.

FASTMIX magnesium plus contains the following available nutrients- magnesium, sulphur, zinc and manganese. This product is rapidly absorbed by the plant quickly correcting deficencies. FASTMIX has been specially developed to meet the micronutrient demand of cereals and other leafy crops with a high manganese demand in an ideal combination with magnesium and sulphur.

IT is a cost efficient nutrient application technique for Mg, S, Mn and Zn without additional costs, if combined with the regular crop protection program. It also helps activate nitrogen into the plant to enhance seed development and transference of sugars throughout the plant, Sulphur is one of 17 elements essential for crop growth.

Although sulphur is considered a secondary nutrient it is often referred to as the fourth major nutrient ranking just below NPK. Sulphur deficiency can often be mistaken as nitrogen deficiency. The pale yellow symptoms of sulphur def often appear on the younger or uppermost leaves whilst nitrogen def initially appears on the older leaves.

Crops lacking sulphur appear stunted, spindly and thin stemmed and maturity in cereal grains is delayed.

When deficient, Mg is transferred in the plant from older to new tissue. As a result, deficiency symptoms occur first in older leaves. Tissue between the veins becomes light green to whitish in colour. In cereals this leads to striping between veins that may be intermittent rather than continuous. With severe deficiencies, purple colouration may follow.

I have observed quite a lot of mildew especially on winter barley crops across the province over the last couple of weeks. Infinity seems to be the weakest variety against this disease but I am also seeing it on other varieties. I am advising a T0 fungicide treatment as rhynchosporium levels are also quite high. It is also important to observe the winter wheat varieties when considering a T0 bearing in mind the low resistance the variety Leeds has to mildew. Whilst this has proved to be an excellent yielding variety it is critical to be aware of this when planning fungicide programmes.

Weed control decisions for winter cereal crops will depend on what has already been done in the autumn and what weeds have overwintered since that treatment. Where no treatment has yet gone onto wheat, OTHELLO is the product of choice, controlling AMG and certain broad leaved weeds (BLW) in this crop in the spring.

However this product is not safe to use on barley, and with the loss of chlortoluron (CTU), there is no spring alternative to control emerged AMG in this crop. None of the autumn products control AMG beyond the mid tillering stage, and in all winter barley crops the AMG will be well beyond this stage now. With the loss of LEXUS CLASS there is nothing to control emerged grass in winter oats.

Unlike the autumn actives, the actives in OTHELLO that specifically control AMG (iodosulfuron and mesosulfuron) are not residual and have no pre-emergent activity, and therefore will only control AMG that has already emerged. In addition they require the weeds to be growing actively, so delay use until all grasses have emerged and temperatures have risen to allow growth to have resumed.

The third active in OTHELLO, diflufenican has residual activity as well as contact and therefore will control a wide range of pre or early post emerged broad leaved weeds. However where these weeds are well established beyond the seedling size, then a contact product needs to be added to ensure larger overwintered BLW are controlled effectively. The cheapest option is DUPLOSAN, improving control of chickweed, fumitory and cleavers, but this product is temperature sensitive, therefore needs a milder spell to work properly.

In past years both IPU and CTU controlled groundsel very effectively in the autumn. However none of the current autumn replacements control this weed, and therefore it is now a common overwintered problem requiring control in the spring.

Other overwintering/late germinating weeds can include chickweed and cleavers. SPITFIRE is a more effective option controlling these and a wider range of other emerged BLW, and is the best tank-mix option with OTHELLO in wheat or for use alone in barley and oats. As it is also a contact post emergent only herbicide, it works also best when the weeds are growing actively.

Brome grass and wild oats

Satisfactory brome grass control can only be achieved using a combination of cultural and chemical control methods over the course of the growing season; no single herbicide treatment is effective by itself. Cultural control methods are based around stale seedbed routines pre-drilling, switching to spring cereals, or the use of a break crop for a season.

Chemical control should have begun in the autumn with CRYSTAL applied at the higher 4lt/ha rate, following up now in the spring with BROADWAY STAR, but note this product can only be used on wheat. There is no spring follow-up product safe for barley; therefore some re-infestation of brome is likely in this crop in the spring.

To maximise the efficacy of BROADWAY STAR, it is important to pay attention to a number of points;

-the smaller the brome, the better the control; ideally not after 3 tillers, GS23

-apply when soil temps at 10 cm are >8ºC and air temp >7ºC for 4 days before and after application

-apply to crops that are actively growing and not under stress

-always use an adjuvant along with the BROADWAY STAR

Because BROADWAY STAR works by contact activity only, any brome or wild oats that germinate after the application will not be controlled. The addition of a residual therefore such as pendimethalin brings control of brome and wild oats germinating after the BROADWAY STAR application.

Growth regulation –

managing tiller numbers

When applied before 1st node, GS31, application of certain chlormequat growth regulators can significantly increase tiller numbers. Chlormequat works by suppressing apical dominance, ie main stem development. In doing so it diverts the plant’s resources into producing and supporting more tillers.

Particularly in wheat but in barley also, more tillers will go a long way towards compensating for low plant counts, ultimately increasing yield.

Optimising timing is important to maximise this effect. The earlier it is applied during tillering the greater the tiller effect, but note early application to increase tiller numbers will also reduce its effect on lodging.

Application of a chlormequat based growth regulator often goes on with a T1 fungicide application sometime around 1st-2nd node, GS31-32. At this timing it is too late to affect tiller numbers and survival but will maximise the stem stiffening effect.

Early application will also increase root growth and so reduce stem-base lodging. Stem-base lodging is where the plant folds over at the soil surface as a result of poor anchorage in the soil, and is caused by poor root ball development, more likely when the seedling develops in wet soils that limit root development.

Only chlormequat works by suppressing apical dominance, but the active itself does not work effectively at temperatures below 8°C. SELON is a formulation of chlormequat in combination with a particular adjuvant mix which enhances the uptake of the chlormequat in low temperature conditions and therefore improve the reliability of performance, consistently working right down to 1°C.

The adjuvant mix also works as a crop safener, particularly when applied in tank-mixes with other pesticides.SELON is very flexible in terms of crop timings and tank mixes.