Alternative methods for terminating cover crops

This field lab investigated alternatives to ploughing or glyphosate for terminating cover crops. The group trialled a range of techniques including roller crimpers.

The idea for this field lab originated when one member sought an opportunity to trial and test the feasibility of destroying cover crops with a double-roller crimper machine, and the other desired to find a way to destroy no-till cover crops without the use of glyphosate. 

In total six farmers opted to be involved on seven field sites, of which two sites were organic. Field sites were in Cambridgeshire, Suffolk, Norfolk and Oxfordshire.

How it works

Cover crops and living mulches are often used to build organic matter and suppress weeds between main crops in rotations. 

However, reduced and minimum tillage cultivation systems which reduce damage to soil structure, have been difficult to achieve in organic systems where ploughing is the primary method of control for many weed species.  Reduced tillage systems have been more readily achievable in non-organic systems which permit the use of herbicides such as glyphosate to control weeds and kill off cover crops. There is some risk of an EU ban on the use of glyphosate.

Outcomes of the trials included: 

·       Trialling examples of different cover crop species or mixes grown on different soil types

·       Measuring the how effective different cultivation methods were on cover crop termination at these sites (where possible the researchers were able to test for statistical significance of results).

It was hoped that the farm-scale trials would allow non-organic farms to reduce herbicide input, and allow both organic and non-organic farms to control weeds more sustainably and improve soil health. 

Trial design

Farm-scale trials compared different termination methods to a control of bare stubble and current cultivation techniques or the use of glyphosate.  The termination methods included:

• Roller Crimper (The crimper-roller method involves killing off a cover crop using equipment that has been developed in Italy and at the Rodale Institute.  An overwintering cover crop of e.g. rye and vetch is killed off and laid flat by rolling when it is flowering.  The following crop is then direct drilled into the dead mulch).
• Mowing (Flailing)
• Rolling (with frost)
• Shallow cultivations (carrier)

The Field lab measured:

•         Efficiency of termination

•         Cover crop establishment

•         Cash crop establishment

•         Overall profit margin impact

The field lab helped evaluate the success of these methods in a farm scale replicated trial, analysed by the researchers, RSK ADAS. It was hoped that this would provide valuable examples of cover crop agronomy that would be beneficial to soil structure and the environment and may well be relied on in a future where glyphosate may be banned.

Cover crop seeds were donated by Kings Crops.