Väderstad Concorde

Interest in various forms of reduced tillage is steadily increasing, in line with today’s high machinery and fuel costs and increasing awareness of harmful effects of soil compaction. Reduced tillage in its various forms does, however, place higher proportions of coarse aggregates and greater quantities of plant residues. In the summer of 1995, the Väderstad Concorde underwent evaluation in field trials. The Väderstad Concorde is essentially a seedbed harrow with a seed hopper installed above it. The seed is fed pneumatically, with each harrow tine functioning as a seed coulter. Depth control is achieved using a wheel which follows the contour of the land, transmitting control signals to the hydraulics unit to raise or lower the machine as required. The Concorde was developed to allow farmers to reduce the number of machinery passes required. The trails encompassed spring drilling (With different numbers of harrow passes and various drilling depth), and involved studies of the bottom of the drill and the seedbed itself to investigate seed placement, the size distribution of aggregates and the moisture content of the bottom of the drill and the rest of the seedbed. During the growing season there followed monitoring of the number of plants, shoots (tillers) and ears, and of yields. The number of weeds at the various stages of growth was also investigated. Another aspect of these trials involved drilling nitrogen fertilizer amongst growing autumn wheat in the spring (drilled both along and across the direction of seed drilling). In spring drilling, an implement with Crosskill rollers was used after the Concorde. The result showed that seed placement after the Concorde in spring drilling was good, with, at lowest, 96% of seed placed at the bottom of the drill. The number of plants per square metre after the Concorde was higher where no prior harrowing had taken place. This indicates that harrowing prior to drilling does not improve the result, provided that the field has been harrowed in the autumn or levelled. In the trail crops which had not been harrowed prior to drilling, pressure on the crop from weeds was lower than in the crops which had been harrowed twice before drilling. The harvest result also indicated that a reduced number of harrow passes before drilling with Concorde produced increased yields. Drilling nitrogen fertiliser in autumn wheat produced increased yields when compared with topdressing, in spite of the fact that a great deal of precipitation fell on the following night. It is difficult to determine whether the increased yield was a result of the tillage effect or the placement of the fertiliser. Even greater effects are probably to be expected if rain does not fall on the crop immediately after the fertiliser is drilled in this way.