Crops continue to power along, but the rain in the past week will inevitably drive our prominent wet season diseases also. As flag leaves appear on winter wheat crops, there is a growing need for increased curativity from the actives in the tank.

Septoria and rhyncho are bound to take advantage of the wet conditions, but perhaps the lower temperatures will at least slow the disease progress.

Last week, I was in Armagh looking at crops with a group of farmers there. The benefit of the good back end was clear to be seen as most crops were totally full and very few crops had patches missing or poor areas following the good establishment. But leather-jackets were common place in spring crops and doing real damage in some of them.

Winter wheat

There is a good bit of winter wheat about this year and it is all carrying a good strong healthy colour. There is also a fair bit of winter barley about and these crops are at various stages of earing out.

The winter wheat I visited was very clean JB Diego sown in early October. There was certainly some septoria present, but the four newest emerged leaves were quite clean and a lovely green colour. This is in contrast with so many crops I have seen over the past month which carried a lot of blotches which were either yellowed or dead.

The Armagh crop was much more pleasing to the eye as it showed no stress. The flag leaves were just appearing and the crop (a first wheat) had been sprayed previously with Gleam and chlorothalonil. It was much cleaner than other crops that had received a much more expensive fungicide mix earlier.

This crop was sown in early October and it had established very well. It had received a dressing of green-waste compost, which may have contained very little available N, but the crop looked very well on 120 units of nitrogen.

This same field had received similar dressings in recent years and it may well be the subsequent nitrogen release from these dressings that was so obvious in the crop last week.

The conditions and colour in the crop led to a discussion on the benefits of improved soil conditions, which is explored on page 48. Whatever the reasons behind the great structure in this crop, it certainly looked like it was worth minding and this can begin with a significant fungicide spend at T2 once the flag leaves are emerged.

Spring rape

We visited one crop of spring oilseed rape which seemed a bit slow and uneven to emerge. The crop had been sprayed with residual herbicide and, while there were no weeds present, it looked like this had adversely affected the crop, for the time being at least.

The vast majority of the seedlings present were only at the cotyledenous stage – an occasional plant had the first true leaves appearing.

But the majority of the cotyledons were stressed. Many had a yellow margin around the edge and some, especially smaller ones, had pink patches on the leaves. The symptoms looked quite like diflufenican symptoms, but this had not been applied to this field in recent years.

It is most likely that the symptoms present were from the herbicide that had been applied to the crop itself. Some of the growers present reported that they experienced slow growth in previous years on crops that received a similar treatment.

Close inspection of this crop also revealed a level of flea beetle damage on some of the cotyledons, but also an amount of cut stems which appeared to be very prominent in places.

The culprit was quickly identified as leather-jacket and big numbers were cutting plants, especially in patches, both above and below the ground. Treatment will be necessary.

Winter rape

We saw a lovely block of ExPower hybrid winter rape which was about 80-90% flowered and visibly going out of flower as the canopy began to take on a green colour again. What caught my eye with that crop was its uniformity. So many crops of rape entered flowering in a very non-uniform fashion this year, but this looked spot on.

The crop had not yet received a sclerotinia spray, as application had been delayed by broken weather. And with 80-90% of flowering complete on most plants, and the petals already shed, this spray is unlikely to be beneficial and so will not be applied.

The crop had been sprayed with liquid N at the start of flowering and this had caused a fair bit of leaf scorch in some of these crops.

Various establishment techniques were used in different fields. Some were planted using the standard Sumo leg method while others were first loosened with the deep legs of the Sumo and subsequently planted with a direct drill.

This latter crop was marginally later maturing, but this may have been more to do with the aspect of the field, as it was north facing while the other was south facing.

These were very impressive crops in that they were so even across the top. And there were a huge number of pods per rachime on the leader stems with lots of subsequent branching in a crop that was very well structured. Weather and disease permitting, this crop appears to have big potential.

Spring oats

We visited a few fields of spring oats which were organic. All were after grass, but one field followed a very old ley. The crops were approaching the two leaf stage, had been rolled following planting to tighten the seedbed and had just been tickle harrowed to knock out weeds.

The harrowing had covered over a few plants with soil, but I imagine that the showers will wash off the soil and let them up again. But the broken showery weather may also help the weeds to survive, weeds which would otherwise wilt when torn up. Time will tell.

The first field we walked into was first oat after three years of grass and it had a lot of plants cut.

Again, the culprits were too easily found – leather-jackets were very abundant and active.

It is possible that they had become even more active since the rolled seedbed was loosened by the weed harrow. Action was needed, but pesticides are not allowed. The roller is key to control.

The field really should be rolled at right angles to the direction of planting so that the roller can firm down into the hollows where damage appears to be worst.

Interestingly, we walked to the field that had been in grass for very many years expecting to find even more leather-jackets there. But there were not. Indeed, there appeared to be fewer plants damaged in that field than after the shorter ley.

One would naturally expect to find more pests following longer leys, especially where the management of the grass was poor. Indeed it was so long since this field was cultivated that it still had very visible potato ridges in it and so if rolling was necessary it would have to be at 90 degrees to the old ridges.

Aphids were very visible on these crops and most were wingless, suggesting that they may have come back up from the ploughed-down grass.

Oats is very susceptible to BYDV but are these aphids carrying virus?

In a conventional crop, one would tend to spray first and ask questions later. But this is not an option in an organic crop. However, it seems that the crop can be sprayed with a soapy water solution to help control these aphids, if necessary.

There was one other interesting aspect to this crop of oats. The soil fertility might be described as medium, but the pH was down in the fours.

Lime was applied but it seemed likely that the amount was insufficient to bring the pH even up to the high fives this year.

While oats is not very sensitive to low soil pH, nutrient availability is and a pH this low would significantly limit the availability of the nutrients that are present in the soil. So the conclusion was to apply a dressing of granular lime, which gives a rapid response, to help rise the pH further this year to help crop growth and yield potential.

Spring barley

The majority of spring barley crops were that bit later than further south and they tended to be at the one- to two-leaf stage, or fractionally beyond that.

The crop I was in was min-tilled and there were a fair few clods on top of the ground but they were all dead. The crop was coming up to the two-leaf stage and had established well.

This particular field was involved in the countryside management scheme which is due to end in the near future.

As a result, it is likely that the owner will move back to winter cropping as he sees this as the only way he can envisage tillage making sense. The spring crop was indirectly subsidised by substantial “other” payments which made having the stubble in situ over winter an attractive component of spring crop margins.

This led to the question as to what is the potential yield of spring barley, or any other crop, in that area? Why should spring barley not yield 10 t/ha rather than 6.0 t/ha? This is a key question for all growers of all crops.

Why are so many crops yielding well below their genetic potential in so many different situations? This is a critical question for all growers and needs to be given much more discussion in groups etc. This discussion needs to start now and is discussed here.