16 December 2000

Directly does it

Direct drilling was the star in trial plots at a lo-till demonstration hosted by SMI (Soil Management Initiative). Tom Allen-Stevens reports.

MARTIN DAVIES doesnt mind admitting that the performance of direct drilling has taken him by surprise. As the manager of CWS Broadoaks Cockayne Hatly Farm, near Polton in Bedfordshire, hes been overseeing the establishment of some MAFF-sponsored trial plots, carried out as part of an SMI lo-till demonstration. The plots have been established on a site heavily infested with resistant blackgrass, with the aim of evaluating the relative merits of various establishment systems.

"I agreed to do the direct-drilled plot just to show growers that it wouldnt work," says Mr Davies. But it has. It was drilled in the first week of October with a John Deere 750A No-till drill. Six weeks later the crop has emerged and looks as strong as the neighbouring min-tilled and ploughed plots.

This was despite some pretty fierce competition from slugs: "There was a lot of trash. Slug pellets were put in with the drill and two applications followed, but it became the M25 of the slug world. If you looked under the trash, they were nose to tail," says Mr Davies.

Normally Mr Davies prefers to use a higher seed rate than the 170kg/ha used here and would apply less pellets, although this year its been crucial to get the formulation right: "Dehydrating pellets are a waste of time with the amount of rainfall weve had."

The min-tilled plots were drilled with a Simba Freeflow and a Väderstad Rapid, while the Rapid also drilled the ploughed plot. Cultivations took place directly after harvest in July, and the plots were drilled right at the end of September. One more plot is due to be drilled in the Spring.

All in all, its been a pretty stern test of the various systems, notes project co-ordinator Alastair Leake. "I would have preferred to have put on a low dose of nitrogen in the autumn on the direct-drilled and min-tilled plots, but with the rainfall it wouldnt have held this year." That said, neither plots are suffering, although the ploughed plot does look greener. The main difference looks to be blackgrass survival.

Blackgrass control started with a stale seedbed. After greening up, the plots were sprayed off with glyphosate at the beginning of September. "Really there was too long a gap between spraying and drilling – the plots were beginning to green up again," comments Mr Davies.

Avadex (tri-allate) followed in mid-October with the main post-emergence spray going on in mid-November. Lexus (flupyrsulfuron-methyl), Stomp (pendimethalin) and oil were applied to the cultivated plots, while Lexus, Hawk (clodinafop-propargyl and trifluralin) and oil were applied to the direct drilled plot.

Although its too early to make assessments of blackgrass kill, this could be where direct drilling comes unstuck, as SMIs Colin Stride explains: "Theres more blackgrass in the direct-drilled plots, but thats exactly what you can expect – there hasnt been much germination before spraying due to the minimal soil disturbance. In the ploughed plot youre likely to get a more drawn out germination, so late emerging weeds will escape control. Where the cultivation is shallowest the flush is quickest, so its the min till plot where you can expect really good control."

So far its direct drilling that has attracted most converts: "If it wasnt for the blackgrass, Id go out and buy a large direct drill to do the lot," says Mr Davies.