10 November 2001

A recipe to follow roots

A late drilled crop doesnt have to be the weakest link in your rotation. Gilly Johnson finds out how to boost its potential

REMEMBER the hare and the tortoise? The same principles apply to drilling date. As canny potato and sugar beet growers have discovered, a late, slow starter can match or even outperform September drillings, given a little extra care and attention.

Based in Norfolk, traditional home to a large root area, Peter Riley of Morley Agricultural Consultants has long experience of advising on the later drilled post-root slot. His advice: step back and put the late drilled crop into context. Consider the profitability and logistics of the whole rotation, rather than focusing on individual crop gross margins. "Keep the whole system as simple as possible. Its no good aiming for a milling premium if you dont have a ready local market, or sufficient storage, for example."

What crop?

For most businesses, the choice boils down to winter or spring wheat or malting barley, with pulses as the outside chance. Gross margin returns are not dissimilar (see table 1) – so its aspects other than finance which will swing the decision.

Following potatoes on the medium to heavy sites, and fen soils, winter wheat is best, because it copes best with difficult conditions, and the drilling window can stretch through into December, says Mr Riley.

On the lighter soils, particularly following sugar beet, theres a Norfolk institution of plugging the gap with quality spring malting barley, sown in December or even, for the very brave, November. Some heavy land growers have been dabbling as well – with reasonable success, he comments. "Malting premiums havent been fantastic in recent seasons, but there is a little more interest for next year. Id advise this choice only if youre confident your land can produce a quality malting sample."

Memories of frost kill and lift have faded in the wake of recent mild winters, but the risk remains. Weigh up your chances – February/March sown spring barley may yet be the best bet in terms of margin, he warns.

"If the farm has a track record for producing good hagberg and protein quality wheats, then spring wheat varieties are an alternative, late autumn sown. But again, you must be reasonably confident of success achieving a milling spec."

One complication this autumn is the legacy of an appallingly wet harvest in parts of Norfolk, leaving soils in a sorry state, with bad compaction. "These growers should be looking to bring fields back into condition. Up until mid-November, wed recommend drilling winter wheat." Only use set-aside as the last resort, and then consider investing in a green cover crop in the spring: "Having a crop of sorts is the best way to repair damaged soil structure."

Dont rush in, he warns. "Be patient. Its not a matter of date – its a matter of soil condition. Try and achieve at least half a days drying after drilling. But if you can drill straight after lifting potatoes, then its a good idea. Soil can slump badly after the harvesting machinery has been over the field. If ruts are left to catch the rain, then you may have to wait a long time before the field is dry enough to come back in."

What variety?

Its a tricky one. Up to now, group 2 wheat Charger has done well in this slot in Norfolk, says Mr Riley. Charger is a fast developing variety, so catches up quickly when late drilled. A weaker strawed type, it benefits from late rather than early sowing; and then theres the chance of a milling premium to offset lower yield. But this years NIAB late drilled results (table 2) show Charger to have had a bad year in the region, "despite good farm yields". Its being overtaken by newcomers, notably Richmond, Deben, and potential milling wheat Xi19.

For spring barley, malting buyers are mainly seeking Optic, with Pearl as the favoured winter cereal, he says. "There are some more coming along which do look interesting – Cellar, for example."

The downside

Theres no getting away from it: late drilling does drag yield potential down. For wheat and winter barley, expect to lose 1t/ha by delaying sowing from September to November. "Yield from a late drilled crop depends on adequate summer rainfall and temperatures which are not too high," he says. "In north Norfolk this summer, we saw late drilled wheats, December sown, do nearly as well as those drilled earlier."

Its the reverse for spring barley when autumn sown; you could see a yield increase of 0.25t/ha. But theres a price to pay in terms of extra protection against rhynchosporium. "This disease is no problem for Optic sown mid March. However, it can be a potential nightmare for Optic sown in December, and control could add £20-30/ha to the fungicide bill. Were keen to investigate the new strob – picoxystrobin – which promises better control."

Establishment

Think wheat bulb fly, which is a threat for wheat and barley. Where you know theres the risk of a problem, dont hesitate – use Evict (tefluthrin) as a seed treatment, says Mr Riley.

For wheat, seed rate has to go up; waterlogging can threaten germination. "Wed be using something like 70kg/ha in September, going up to 170kg/ha in late November. On heavier soils, and where theres a slug problem, then perhaps it should be higher still…" Spring barley seed rate should stay the same irrespective of sowing date, "except on heavier soils".

Mr Riley doesnt agree with starter fertiliser, and is equally luke-warm about nutrient products which claim to boost rooting. "Id question the need. Beet and potato crops leave good N residues behind, and harvesting and cultivations will mineralise soil nitrogen."

Weed control

Blackgrass is not so tricky with later drillings – theres more time for the early germinating weeds to appear, and be clobbered. However, annual meadowgrass can be a headache, particularly for the autumn-sown spring barley on lighter soils.

Pre or early post-em Avadex (tri-allate) is one solution which also does wild oats; new pre-em Crystal (flufenacet with pendimethalin) could be another, but theres a cut-off point of 31 Dec on approved use with winter cereals. It is not clear whether treatment of a spring crop, sown before the end of the year, would fall into this category.

"PicoPro, the new pendi-methalin/picolinafen product, has a similar question mark over use with autumn-sown spring barley. Approval is for winter cereals and gives a cut-off date of GS30."

Stomp (pendimethalin) has pre-em clearance, but the residual action needs moisture, so this may not be a good choice as spring approaches. Tolkan (IPU) has an off-label approval on spring barley."