25 February 2000


Variety-specific growth

regulator programmes

proved their worth on a

Hants Farm last season.

Andrew Blake explores the

policy now pursued by the

farmer and his independent

crop consultant

KEEPING wheat crops standing at Hyde Farm, Herriard, near Basingstoke involves boosting root anchorage and strengthening stem bases as much as shortening crops. That is the belief of long time tenant Peter Cheyney and his agronomist of three seasons, Emma Saxton of Hampshire Arable Systems.

The key, they say, is matching regulator treatments to individual fields and varieties. Cuts in seed rates and more timely nitrogen applications have also helped.

Most of the land is clay cap about 180m (600ft) above sea level and grows wheat interspersed with oats, oilseed rape and linseed. "Our big problem up here is take-all so we only have first wheats," says Mr Cheyney.

Two harvests ago the 283ha (700 acres) all-arable unit suffered bad lodging with average wheat yield down to 6.8t/ha (2.75 t/acre). "We normally hope for about 3.5t/acre."

Chlormequat failed

Apart from the weather, earlier drilling and first-time use of dried sewage sludge didnt help. "We probably didnt cut seed rates enough."

But the standard split chlormequat programme also failed to cope with the challenge. "Until then we used a fairly blanket approach not particularly variety-driven."

As a result of the experience Miss Saxton suggested more targeted strategies on two varieties, Rialto and Consort.

The first, based on two 0.2 litre/ha applications of Moddus (trinexapac-ethyl) with some chlormequat at both GS30 and GS32, followed by 0.5litres/ha of Terpal (2-chloroethylphosphonic acid + mepiquat chloride) at GS35, was aimed mainly at reducing Rialtos height.

The second, involving an early application of Moddus with chlormequat, and a second chlormequat but no Terpal, was intended to improve Consorts rooting and the strength of its stem bases, explains Miss Saxton.

"The principle is that even though Consort has a NIAB rating of 8 for standing, that clearly wasnt good enough the year before."

Although the two growing seasons were very different, all other inputs were similar, making the 1999 exercise a useful comparison. Average output was 9.9t/ha (4t/acre) with some Consort running to 11.7t/ha (4.75t/acre), says Mr Cheyney. "Everything stood up although some of the Consort was borderline."

Total nitrogen input, including some late urea, is usually about 200kg/ha (160 units/acre). But a move to apply various bulky organic fertilisers to boost the humus content of the soil has made it harder to judge the correct amount. "We used to have stock here, but not any more," explains Mr Cheyney.

Terra cake

Latest introduction is Terra cake, a form of dried sewage sludge. It is applied at about 40t/ha (16t/acre) after oilseed rape and ploughed down before wheat sowing. Composted garden waste is also being tried.

"We used to go up to 190 units/acre on Group 1 varieties before we had the cake."

Both organic materials release nitrogen slowly, so soil mineral N tests may be tried to assess crop needs more accurately, notes Miss Saxton.

Depending on sowing date, seed rates for the mainly home-saved seed have been trimmed from 300-400/sq m to 250-300. Concern for slug damage after oilseed rape makes the pair wary of cutting much further.

Sludge-treated Claire wheat needs carefully controlled regulator and nitrogen inputs this season to avoid encouraging unwanted tiller survival, says Emma Saxton. The bulky manure is needed to build up organic matter on the stockless farm, explains Peter Cheyney. Other sources are also being tested.


&#8226 Varieties driving programmes.

&#8226 Organic manures complications.

&#8226 Root strengthening for Claire.

&#8226 Straw shortening for Spark.

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