Special "Alternative Methods for Haulm Desiccation"

With the ongoing discussion about the re-authorisation of the dominant chemical siccative, interest in alternative haulm reduction methods on potato farms is increasing again. For this reason the Special “Alternative Methods for Haulm Desiccation” will provide not only a comparison of the systems of different chemical methods, but also different mechanical methods such as flailing or plucking and cutting. The effects of physical-thermal methods, whether by use of flame guns or electricity, will also be shown.


In conventional cultivation, desiccation alone or a combination of flailing and desiccation have proved successful, as in most cases haulm topping on its own is not sufficient as a haulm reduction measure to avoid regrowth of the stands and the associated impairment of yield and quality. At present four chemical siccative agents with different reaction speeds and efficiency levels for complete termination of the plant growth are available in Germany.

The comparisons will be supported by the firm Belchim Crop Protection.

Flail-type haulm toppers

With the haulm toppers, depending on the goal and the machine setting, the potato haulm is either placed on the ridge or conveyed between the ridges. The latter is essential when the haulm topper is preparing for a chemical measure. Then the stalks must remain accessible. In this case it is important to ensure optimal flailing quality. When using the generally four-row haulm toppers, however, the complete stand must be driven over, row after row, so that the haulm treatment date will depend much more strongly on the soil moisture content than is the case with a field sprayer using the tramlines. In addition, in haulm topping, especially in reproduction cultivation, there is a growing risk of virus and bacteria transfer that counteracts the goal of healthy plant production.

The haulm topper will be provided by Messrs. GRIMME Landmaschinenfabrik GmbH & Co. KG.


Thermal haulm reduction

In practice equipment with a working width of 3 m prevails for thermal haulm reduction so that by comparison with a plant protection sprayer the area output is much lower. In thermal haulm reduction the energy source is gas which is converted into heat via different burners with an open flame or via special infrared radiators that damage the plant cells, but do not burn the plants. In order to use the heat for as long and as effectively as possible, the through-going combustion chambers of the equipment are closed by solid or flexible boundaries and some also have supporting fans for better distribution of the hot air. To achieve a far-reaching heat effect, a much lower driving speed than for the first application is necessary, which involves a correspondingly higher gas consumption rate coupled with a further reduction in the area output. Flaming is used for final desiccation of the residual stalks in organic cultivation. 

The equipment for flaming of the potato haulm will be provided by Messrs. Ruthenberg.


Electroherb method

In the electroherb method, high-voltage electricity is passed through plants via metal applicators and the electric circuit is closed with a second applicator on the ground or further plants. Cells in the leaves, stems and roots through which the electricity passes are destroyed far enough without relevant heat effect so that the water supply in the plant is interrupted and the plant dries out. As no soil is moved, the habitat is preserved undisturbed and as far as can be seen from the current status of trials, when used in normal agricultural application contexts there is no relevant damage to organisms living in the soil. As with chemical herbicides, but without the disadvantages of residues and waiting times, the electroherb method can be applied with correspondingly low and uniform dosing for desiccation of field crops. The results of the second trial year for potato desiccation will be presented for the first time at PotatoEurope 2018. The goal here is to provide an efficient alternative method for wide-scale use in agriculture that is suitable for producing high-grade potatoes in an environmentally safe manner without chemical desiccation agents, and if possible without any further mechanical or thermal methods too.

The electroherb method will be presented using equipment from Messrs. Zasso.


Haulm pluckers

After flailing, it is also possible to use multi-row haulm pluckers that pull the stalks out of the soil and thus interrupt the connection between the residual stalks and the tuber nest. In combination with the haulm pluckers or as solo items of equipment, root cutters can also be used that undercut the ridge with broad blades and aim to further limit the risk of plant regrowth. 

With kind support from Messrs. REMA.




The Special “Alternative Methods for Haulm Desiccation” is being conducted by DLG in close cooperation with the Lower Saxony Chamber of Agriculture, the Dethlingen Experimental Station (VSD) and the seed producers’ association SEG (Saatguterzeugergemeinschaft in Niedersachsen e.V.).