Yield variability seems to be the overriding feature of this harvest for our agronomists, while thoughts start to turn to autumn establishment and weed control. Dominic Kilburn writes.
As much as 90 per cent of oilseed rape crops and most of the wheat had been harvested, said North Yorkshire-based AICC agronomist Andrew Fisher, speaking in mid-August, however wheat harvest further north, in Durham, was just getting underway.
Oilseed rape had yielded well, the thinner crops earlier in the season filling out nicely, resulting in “a good average” of 3.9-4.0t/ha and the best at 4.3t/ha, he reckoned.
“We had pockets of downpours in June, but, like a lot of the country, most places were dry for two months and I think that the good establishment last autumn and fertile land kept them going through the dry times,” commented Andrew.
“Like the rape, the wheats on the most fertile land have also done well, delivering 11.5t/ha on the best sites compared with the really heavy land crops that sat in wet soils last winter and which struggled to tiller, and ended up yielding around 7.0–7.4t/ha.
“Winter barley did well too on the better land, it matured before the drought hit and also provided growers with good yields of straw which has value,” he added.
According to Andrew, a significant amount of recently-arrived rain will set things up nicely for OSR drilling, although he admits that, in seasons like this, it’s hard to hold growers back when their fields are cleared by an early harvest. “One of my growers has already started drilling rape into winter barley stubble which is a bit early for my liking.
“Ideally the last week in August is best otherwise crops get too lush and then have to be held back with PGRs,” he pointed out.
He said that most of his arable-only farms will be establishing OSR with a band of DAP next to the seed to encourage quicker establishment, while his mixed farms look to spread slurry or muck on fields to drill into, to give crops a boost and grow away from the threat of flea beetle.
“One farmer suggests that chicken manure gives establishing OSR crops the best kick-start due to its high loading of nitrogen, and, based on last season, it seems to work as he didn’t have to spray for flea beetle at all,” said Andrew, who reminded growers that rolling the seedbed is critical, especially if a subsoiler has been used to drill the crop.
“A few of my growers still prefer the option of applying a pre-emergence herbicide to OSR, but I prefer an early post-em treatment when you know what’s coming up.
“If cleavers is the target then a Centium (clomazone)-type product can be applied at pre-em, while some have switched to Clearfield varieties and go with metazachlor at the cotyledon stage before the CL herbicide is applied.
“Banastar, with its three actives of dimethenamid-p + metazachlor + quinmerac, is something I use for poppy and shepherd’s purse at early post-emergence,” he added.
Andrew suggested that there was very little between varieties – hybrid or conventional – in terms of speed of establishment in the autumn and stressed that performance at that time of the season mostly came down to seedbed conditions and available moisture.
He also noted that there had been a slight shift in favour of growing conventional types by his growers.
A growing menace
While meadow-grass remains the greatest threat in the region to winter wheat, black-grass continues to be found in ever increasing numbers.
“I’ve recently had long conversations with a grower who wanted to put a second wheat in a field which has high black-grass populations and the message that they must not drill until at least October is one that must be hammered home,” stressed Andrew.
“My growers don’t like to drill late especially when they have harvested crops early, and the start of October is probably about the latest they can be reasoned with to drill. One of my growers who farms at 600ft wanted to start drilling wheat in the last week in August but hopefully I have persuaded him not to!
“We may find that black-grass germinates early this autumn because of the heat over the summer months and some growers have already been out with stubble rakes to get it to chit.
“There’s not much sign of slugs as yet but you can bet they will be hungry when they eventually get the rain to bring them to the surface.”
Meanwhile, for meadow-grass, Andrew will recommend a pre-, or early post-em application of Liberator (flufenacet + DFF), with a follow up of pendimethalin if required, and timed with an aphid spray.
Over recent weeks, Andrew has been soil sampling across many of his farms and will be advising growers to make the most of farmyard manures in an attempt to reduce the overall cost of nutrition, particularly with the price of fertiliser on the rise.
Finally, although yield is of course important, Andrew’s wheat variety selection for the season ahead prioritises those with resistance to septoria, as well as stiff-strawed types such as Grafton, which performed very well this season, bearing in mind his mixed farms and the value of straw.
Andrew Fisher can be contacted via email: [email protected], or tel: 07836711918.
Nottinghamshire-based agronomist Christina Scarborough said that there had been a wide variation in yields this harvest and cited the prolonged wet weather in the late autumn and winter that did the damage to the poorer performing crops, more so than the drought during the summer, she thought.
“That said, some of the newer wheats we tried – including Shabras and KWS Siskin – did very well, and it could have been because of their extra vigour in the autumn which allowed them to get their roots down a little further.
“Those crops didn’t die off so quickly in the summer and remained greener for longer, and they were certainly the standout varieties for yield,” Christina added.
Speaking in mid-August, she said that growers were patiently waiting for sufficient moisture to begin oilseed rape drilling, however, with the ground still “rock hard”, there was little point in trying to pull any machinery through the soil at the moment.
In terms of up and coming OSR weed control, she suggested that a pre-emergence herbicide in oilseed rape was a risk not worth taking and that growers are better off waiting to see the plant stand before applying a herbicide.
“A pre-em can also cause crop knock-back, just at the time when you need it to be establishing fast,” she explained.
“Three years ago I had some OSR trials within a field, where a pre-em was not applied, and the trial crop was three times the size compared with where a pre-em had been applied.
“While missing out on a pre-em might not be ideal for those that might also want to apply glyphosate if there are surface weeds, it’s advantageous to go in at full cotyledon with a metazachlor based product, which can do a good job without knocking plant vigour.”
With cranesbill being one of the biggest weed challenges, Christina said that she is looking forward to trying the latest post-em OSR herbicide from Corteva, containing Arylex, which is claimed to have good control of cranesbill, cleavers, poppy, shepherd’s purse and fumitory.
When sufficient rain does arrive, and cultivations ahead of wheat drilling can get underway, Christina said that she is hopeful that this season’s pre-emergence herbicide stacks can mirror the performance of last year’s. “I had fields of wheat that went from being written off in 2017 because of black-grass, to producing good crops this year.
“It was the combination of autumn pre-ems working exceptionally well in combination with use of new grass weed product Monolith (mesosulfuron + propoxycarbazone) in the spring.”
With grass leys also on her mind, some much-needed rain will go a long way towards helping to produce the fine tilth required to establish them successfully, she concluded.
Christina can be contacted via email: [email protected] or tel: 07969507082.