In the management of potato crops on conventional farms, the current focus is on the optimal application of herbicides in the pre-emergence stage. With the combination of laying and final ridge construction in one operation, the ridges can settle very well over a longer period of time. At the same time, similar to the creation of a "false seedbed", a large proportion of the weeds run up from the upper soil layer, which can then be easily controlled shortly before the potato plants push through. With today's crop protection sprayers and the widespread use of furrows, high area performance is ensured for on-time treatment and quality-preserving use of only selected furrows.
Dr. Rolf Peters
The advantages associated with this process configuration are still valid, but must be increasingly questioned due to the changing basic conditions. This concerns, on the one hand, the expected expiration of the approval of the previously dominant active ingredient in various pre- and post-emergence herbicides and, on the other hand, the political objective of a significantly greater reduction of chemical crop protection in agriculture. The latter, of course, also concerns the potato and is relatively easier to realise in the care of potato crops than in the control of diseases and insect pests, such as the yield-critical late blight.
In the case of the potato as a classic root crop, the multiple tillage passes used to take over the function of loosening the soil, repeated weed control and step-by-step ridge building. With today's more powerful tractors, soil loosening and ridging can also be carried out in a single pass, e.g. in combination with potato harrowing. This has meant that the further development of separate care equipment has not been a particular priority for most manufacturers in recent decades.
Against this background, many farms still rely on a combination of harrowing and multi-stage ridging for mechanical maintenance in order to repeatedly prevent the weeds from developing further by tearing them loose and burying them. However, the intensive soil movement also stimulates deeper-lying weed seeds to germinate, which then further increase the competitive pressure. A different approach is taken by maintenance equipment which, e.g. by means of feeler wheel-guided knives or ridge formers with fixed brush bars, removes only a shallow layer of the previously built-up final embankment at a time, together with the weeds that have grown up there, and leaves the underlying soil layers untouched. A challenge here, however, is an optimal adaptation to the ridge shape, which often already varies from farm to farm.
Although the ridge can be rebuilt in the same operation using trailing cultivation tools, it must be taken into account that the preferred soil conditions for weed control and ridge construction are not congruent.
While the ridge flanks can be worked relatively well by the maintenance equipment available on the market, the crown area is much more difficult to keep weed-free, especially in the post-emergence stage. In addition to various harrow tools, differently designed finger discs are also used here. In addition to various harrow tools, finger discs with different designs are also used here.
Due to their relatively slow juvenile development, the potato plants can only suppress the weeds sufficiently at a late stage, so that, according to experience, 1-2 care rounds are still necessary on many sites even in the post-emergence stage. However, the above-ground development of the potato plants is accompanied by an increasing root penetration of the ridge, which suffers more damage when the soil is mechanically tilled, the more intensive and the later the intervention. This is then also reflected in the yield and grading of the crop. In addition, many more furrows have to be repeatedly worked than with chemical care. This not only leads to increased soil compaction, but can also result in clod formation if conditions are too wet, the effects of which can be felt right up to harvest. Together with the increasing pressure of deadlines due to the growing cultivation area, the desire for larger working widths has therefore increased significantly in practice. A GPS-controlled laying operation favours the use of cultivation equipment with a working width that exceeds the number of rows of the laying machines, as do the more powerful engines of today's cultivation tractors.