Crop Watch: Deadline to spread urea fertiliser approaches

This week brings the spring equinox, with days being longer than nights, and hopes for more spring-like weather.

Many hard decisions are now being made on whether to redrill, keep or bin struggling crops.

Time is also running out for spreading conventional urea fertiliser, with the impending cut-off date at the end of the month.

Our agronomists consider the challenges in the coming weeks.

North

Patrick Stephenson – AICC (Yorkshire)

It would be very easy to write the shortest Crop Watch ever. Not all the crops are “doomed” as Private Frazer would say, but it is difficult to remember a period which has been as wet as this for as long as this.

Will we look back at this year and rank it alongside the winter of ‘63 and summer of ’76 as memorable?

Drilling earlier in the North has certainly helped most of my growers and although we have lost some fields to waterlogging, we do have some good crops.

It is hard to be positive about oilseed rape as the cabbage stem flea beetle and rape winter stem weevil are still claiming some crops.

On the best crops flower buds are clearly visible and we are battling hard to get nitrogen applied.

Most of the varieties have good light leaf spot resistance which helps me justify a no-spray approach, and more truthfully, we can’t travel.

Many of my growers have high erucic acid rape (Hear) crops.

These have lower disease ratings and are very leggy, so we will be trying to get these sprayed for growth regulation and disease control.

Winter barley managed to stay green and healthy for most of the winter, but the last three weeks has seen the return of its natural winter yellow.

Battling to get nitrogen on has been an issue and with the 31 March urea deadline rapidly approaching, any plans for splits is going out of the window. 

In good old Yorkshire parlance, they are having “a good do”.

Mildew is easily found in all crops and, depending on variety, rhynchosporium and net blotch are also easy to find.

In theory, I try and treat the winter barley with three fungicides covering a key 10-week period.

Like all great plans, this gets carved up by the season and it ends up being two.

Plan A sees me hoping that at the end of the month crops will receive a growth regulator, weed control and a fungicide.

In the two row crops I prefer to front-load my programme with a robust prothioconazole/SDHI mix. For the hybrids, I like to split my big hit between now and ear emergence.

Wheat crops

Winter wheat crops are a real mix and some resemble a patchwork quilt of bare soil and crop. I know that many growers are debating whether to leave it, redrill or bin it.

As the weeks tick by with indifferent weather, the redrilling option starts to fade away. As painful as this may be, it is the most practical and profitable option.

Nitrogen is now becoming a priority and although applying a little early was the plan, we will sadly adopt the “a good do” approach. T0 sprays will target yellow rust and the first pustules can now be found.

My learned colleague Bill Clark would advocate spraying as soon as you see symptoms.

In my experience this is not always the best practice, particularly this early in the season. We will wait until the end of the month before spraying.

It took an age for the manufacturers to get their fungicide pricing strategy out as concerns over the area likely to be sprayed, and the arrival of further new chemistry congesting the marketplace.

One thing is certain – the very good value of prothioconazole. The poor state of many crops will impact on spray programmes as growers look for the best value.

Finally I am clutching to the belief that this season will be like the old proverb, “the darkest hour is just before the dawn’”. Let’s hope the sun appears soon.

South

Alice Whitehead – Zantra (Essex/Kent)

Although rainfall is the main talking point, we are aware of how fortunate we have been in this south-east corner compared with our farming colleagues further up country.

Locally, my sympathies lie most with the veg farmers who have been battling the elements most days, cutting brassica crops, and struggling to establish crops for harvest in late spring.

Cereal crops are looking well, and there has been the odd opportunity for some applications of nitrogen, sulphur and even contact grassweed control due to the mild weather and active growth of crops and weeds.

Where there are ryegrass and brome to clear up, my product of choice is normally the co-formulation of pyroxsulam + florasulam, with the added bonus of some broad-leaved weed control, as there are normally groundsel and cleavers to tackle. Iodosulfuron + mesosulfuron-based products will be used for blackgrass. 

Some dirtier crops which have missed the autumn pre-emergence herbicide have been written off and will be replaced with a spring crop.

Oilseed rape

Oilseed rape has enjoyed the warmer temperatures and is extending and even flowering in some cases.

Crops have received an application of Korvetto (clopyralid + halauxifen) earlier in March where required for a clean-up of groundsel and mayweed, and have also had a tebuconazole + prothioconazole mix to protect against light leaf spot. 

I added some foliar boron due to the amount of rainfall and the light soils these crops are on. 

Downy mildew is easy to find in most winter beans drilled in the autumn, although they should be OK to wait until the first fungicide timing at early flowering.

Again, where these crops missed the pre-emergence herbicide, there is a lot of weed, particularly mayweed. I will attempt to target these with bentazone later in the spring.

East

Ryan Baker – Frontier (Suffolk/Norfolk)

Despite setting out not to talk about the weather in my Crop Watch articles, so far I have started each column with just that. Every glimmer of hope for a few dry days has been dashed with more forecast rain.

Except on the very lightest land, very little spring land work has yet to be carried out. Patience is going to be key in order to not exacerbate soil damage.

So far, oilseed rape is looking promising. Despite the presence of larvae, stem diameter seems to be providing some resilience against the pest. Where pigeons have been deterred, the crop is almost a month ahead, with the most advanced crops above the knee by mid-March.

Hear varieties in particular have exhibited strong spring vigour and a specific fungicide with plant growth regulator activity has been utilised at stem extension to reduce the dominance of the main stem.

Variable crops

Cereals drilled after the late October deluge are struggling. However, crops drilled earlier look well, and wheats drilled in the cold and drier new year period are establishing nicely.

Excess water has left crops looking very variable and rooting poorly. Methods to promote tillering and rooting will be crucial.

If it ever dries out enough before stem extension, rolling can increase tiller numbers. Early nutrition, both nitrogen and phosphate, can also promote tiller retention.

Uneven crops provide a good opportunity to make the best use of variable rate nitrogen. Phosphite’s ability to aid rooting is also well documented.

Where applied, residual herbicides in cereals have worked well, with cinmethylin again being the standout active.

However, in crops that have not received any herbicide, the blackgrass is reaching a growth stage where the move to contact chemistry, rather than residual chemistry, is now appropriate.

Winter barley is sink limited and maintaining tillers now is vital. Mildew is easily found in older and malting varieties, whereas brown rust is prevalent in many hybrids.

This year a T0 fungicide is likely to prove worthwhile. As well as this, the use of a plant growth regulator at growth stage 30, especially in hybrid varieties, is likely to strengthen crown roots and reduce the risk of root-based lodging.

Standard sugar beet seed has been arriving on farm this month and with Cruiser SB (thiamethoxam) now authorised, treated seed will soon be delivered for those who opted for this.

First aphid flight is forecast for 10 April, but will there be any beet in the ground by then?

West

Gavin Burrough – Pearce Seeds (Dorset/Hants/Wilts)

Only a handful of spring cereal fields have been drilled. This week would have hopefully seen some more drills moving, but showers of rain are still on the forecast so I imagine progress will be slow and steady.

This unsettled weather is making pre-emergence herbicide decisions on spring cereals more tricky, as the last thing we want to do is apply a pre-emergence herbicide and then have it followed by another heavy dose of rain.

Residual herbicide applications which were made to winter cereals last autumn have generally done a good job, although there are plenty of fields which did not receive an autumn herbicide which are now looking very weedy.

On winter wheat, spring contact herbicides are planned to try and tidy up the grassweed burden. Spray days have been few and far between so I suspect the majority have yet to be applied.

Making application decisions trickier is where the crops are stressed from having wet feet over the winter.

The last thing we want to do is stress them as soon as they try to start growing again. Application should not be made until the crop is looking healthy enough.

Priority is to get some nitrogen on to these crops to try and get them growing again as soon as ground conditions allow. Fields will be very patchy this year and may not look pretty.

Septoria

A lot of wheat crops are carrying high levels of septoria so T0 sprays will be planned where possible, I would hope that we can travel on the majority of fields by the end of March, but time will tell.

Trace elements will be applied where required at the T0 timing to help get crops growing where they have struggled all winter.    

A few growers managed to drill some wheat in January during a few dry days. These have generally established well or been badly hit by rooks and decisions on whether to keep these will soon need to be made.

Winter linseed is generally looking good and crops have started to grow away.

Post-emergence broad-leaved weed control is required as soon as conditions allow using amidosulfuron and/or metsulfuron. Zinc will also be applied with the herbicide.  

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