How soil is so important
By John Allan
TRIAL results from an establishment trial on Velcourts brash land trial site at George Farm near Stamford, Lincs, show just how important soil conditions can be.
In 1994/95 direct drilled winter wheat gave the best financial return. According to rates set by the Central Association of Agricultural Valuers, it cost just £19.76/ha (£77.99/acre) to establish. This year the best result came from spending £88.59/ha (£35.85/acre) on precision drilling the crop into a ploughed seed-bed.
Indeed, the next best yields all involved the plough and press, with establishment costs of up to £110.75/ha (£44.82/acre). That compares with just £12.10/ha (£4.90/acre) for stubble drilling.
Seed-beds were very dry on September 27 last year, when the non-replicated blocks were drilled, whereas in 1994 they were nice and moist, comments farm manager, Simon Boughton. He feels this suited direct drilling and minimum cultivation. In drier conditions last year the brash soil at George Farm benefited from the plough and press, which gave a kinder seed-bed and better growth rates.
"You need flexibility in your plans," stresses Mr Boughton. His target this year is to drill 125-250 seeds a sq m after cultivation, decided by soil type, weather, soil moisture reserves and rotation – preferably during September.
Precision drilling produced impressive results this year. When the plough and press was followed by a Herriau Turbosem precision drill the return was £200/ha (£78/acre) better than that of the previous years star, the stubble drilling Unidrill at 300/sq m (250/sq yd).
"The Turbosem gives a perfect 1in depth and regular spacing. This gives the plants a running start, good tillers and a good root system," says Mr Boughton. It also allows a lower seed rate.
Sowing at 60/sq m (50/sq yd) yielded 9.5t/ha (3.8t/acre) stepping up to 10.8t/ha (4.4t/acre) at 120/sq m (100/sq yd) and a top yield of 11.4t/ha (4.6t/acre) at 200/sq m (167/sq yd).
Keeping up to speed in preparing seed-beds is also important. A parallel sowing date/seed rate trial resulted in a loss of over 2t/ha (0.8t/acre) in blocks of Brigadier sown on November 1 compared with Sept 1 or Oct 1. "Even increasing seed rates from 125 to 375/sq m did not compensate for a late start in cold soil," says Mr Boughton.
In the trials most top yields came from using 125/sq m. But both direct drilling with the Unidrill yielded 8.7t/ha (3.5t/acre) and broadcasting using an opened up drill and following power harrow gave 8.6t/ha (3.5t/acre) from a higher seed rate of 250/sq m. Top rate of 375/sq m (314/sq yd) didnt hit the heights with any system.
In case of a wet autumn like 1992 it helps to know that broadcasting did well in the 1994/95 trials, he adds. In that year he applied the seed using a pneumatic spreader, but it emerged in lines.
For the 1995-96 crop he opened up a drill to allow an even spread, but it still came up in rows. His conclusion is that the contra-rotating tines of the following power harrow lined the seed up. If the autumn is wet he will resort to spring tine cultivators.
which served him well in 1992.
Wheat establishment trials – 1995-96
All blocks sub-soiledCost ofCAAVSeed rateReturn/ha
plus2 – discseed drillcultivations/sq m fornet of seed/
3 – roll(£)cost (£/ha)best yieldcult costs +
4 – plough, press, roll(t/ha)area aid
5 – plough, press
0 + Unidrill**4m-23,50012.10250 – 8.7t/ha831.60
2 + Broadcast/harrown/a72.07250 – 8.6t/ha761.52
2 + Simba4m-26,55366.71125 – 8.7t/ha794.49
2 + Sulky SPI4m-16,50083.55125 – 9.8t/ha888.75
3 + John Deere No-till3m-24,01955.30125 – 9.1t/ha846.30
3 + Unidrill4m-23,50055.30125 – 8.3t/ha765.50
4 + Unidrill4m-23,50093.20125 – 9.9t/ha889.20
4 + Simba4m-26,553101.31125 -10.3t/ha921.49
5 + Sulky SPI4m-16,500110.75250 -10.5t/ha914.75
5 + Herriau4m-27,83088.59200 -11.4t/ha1,034.81
**Best margin in 1994/95. Bold margins beat last years system winner.
• 1995 – best return from Unidrill in topped stubble – cultivation cost £19.76/ha.
• 1996 – precision drill after plough and press best at £88.59/ha.
• 1996 – best yields from 125 seeds a sq m in six out of nine trials.
• 1995 – 300 seeds a sq m best in five out of seven trials.
• Flexibility needed when deciding establishment system.
Precision drilling into a ploughed sed-bed proved the most cost-effective approach in Velcourt trials at George Farm, Lincs, this year.