Soil & seed quality are high on eastern agenda
For the second of our
articles profiling Farmers
Weeklys 1999 barometer
growers Andrew Blake
travels to Norfolk
IN his quest for good crops, many grown for seed, soil condition is never far from Robert Salmons mind. Crawler tractors have long replaced large four-wheel drive models for all primary cultivations at Hyde Hall, Great Fransham. Last autumn revived his fears of the deep compaction troubles that giant beet harvesters can cause.
About half the 507ha (1253 acres) of cropping is winter wheat, of which 84% this year is for seed. Sugar beet and oilseed rape account almost equally for 104ha (260 acres), with peas and grass for seed providing a triple break for early generation wheat seed.
The farm also grows blackcurrants, has a small area of asparagus and carries out contract ploughing/discing and sugar beet harvesting. "We thought it important to diversify into having more enterprises less heavily dependent on EC subsidies," says Mr Salmon who runs the family farm with wife Margaret, employing four full-time staff and casual labour.
"On our sandy clay soils maintaining good soil structure is paramount," says the former FW Cereal Grower of the Year. The land, near Dereham is only a few miles from blowing breckland sand but is very different, he explains. "It tends to be sticky and doesnt take frost very well." Achieving decent sugar beet seed-beds means ploughing and furrow-cracking early in good conditions to maximise over-winter weathering.
Last year, with 777mm (30.5in) of rain, was the wettest since 1982. Nearly 150mm (6in) fell in Nov and Dec. "The severe rutting and damage to soil structure caused by six-row tanker sugar beet harvesters and trailers seen on many Norfolk fields must be of great concern."
Axle loads of over 16t are common on such machines and consolidation beneath them has been measured below 800mm (30in). "Thats well beyond the depth at which it is practical to do any remedial sub-soiling." Such damage on soils of low clay content with little chance of natural re-structuring could last 20 years, he believes.
"The camouflaging effects of wide tyres should not be overlooked," he adds. "Topsoil compaction is mainly due to ground pressure, whereas high axle loads damage the subsoil almost irrespective of tyre size."
Mr Salmon acknowledges that the farm, with its rubber-tracked Caterpillar Challenger 370hp 85D and metal-shod 250hp D7, could be considered over-mechanised. But it is a policy, backed by contract income, which should pay off, he believes. Today he relies on a three-row beet harvester, a six-row machine having been dropped because of compaction concerns.
With the exception of the combine, a Claas 490 25ft cut machine, maximum acceptable axle load is 10t. "And we usually try to limit it to 8t to reduce the need for sub-soiling."
• 507ha arable
• Cropping: ha
Sugar beet 49
Grass seed 43
Spring peas 36
• Sticky sandy clay loam.
• Soil structure paramount.
Soil structure at depth has a big influence on crop productivity, Robert Salmon believes. He no longer uses heavy wheeled tractors for primary cultivations.