Rolling cover crops during the intercrop period

Technical articles

Management of cover crops in arable farming Collaboration and cooperation in agriculture Climate resilience Soil cover Weed control in arable farming

The objective of rolling is to injure the plants and lay the cover crop on the ground by passing a roller. Several conditions must be met to ensure effective destruction of the cover.

Description of the technique

Firstly, rolling is only effective on tall and developed vegetation. The mechanical factor comes first: a developed plant can be injured in several places, multiplying entry points for cold, heat, pathogens, or pests. Secondly, it is known that from flowering onwards, plants are much more sensitive to this mode of destruction: the plant's reserves are then redirected towards reproduction rather than vegetation.

Regarding operational conditions, it is generally recommended to roll during a frost: plants that would normally survive the cold will have their tissues made brittle and deeply damaged by the roller, leading to certain death. The need for frost will be even more necessary if the tool is not specialized (smooth roller, too light, etc.) or if the cover crop is too weakly developed (late sowing date, species resistant to rolling and/or lack of soil fertility). It is also commonly said that rolling should be done on frozen soil to avoid damaging the structure, but generally, a well-covered soil will freeze less easily and it is the biomass of the cover crop itself that will act as a buffer. However, be careful about the weight of tractors operating at this time, although the power requirement is minimal for this type of operation.

Different types of rollers

Flat rollers and Croskill rollers

These rollers, commonly used on French farms, are versatile because they can be used for destroying cover crops, but also during crops sowing to finalize establishment or to firm "blown" soils after winter to improve the rooting of winter cereals. For cover destruction, these rollers should mainly be used under frost conditions, allowing the plants to be "brittle". The possibility of large widths (up to 9 m) allows a high work rate.

Advantages: versatile, inexpensive, high work rate, to be used during frost.

Disadvantages: Less suited for rolling cover crops.

"Rolo-faca" (Brazilian) or "chopper roller"

These rollers have been specifically developed for destroying cover crops. They are very aggressive (cylinder equipped with angle irons that injure the plant by speed effect), but with small working widths. They require a specific investment.

Advantages: effective, can be used at any time on dry soils.

Disadvantages: requires investment, low work rate.

The Chambers of Agriculture of Charente-Maritime and Deux-Sèvres have conducted a comparison of the effectiveness of 4 chopper rollers on green manure destruction, with demonstration videos of these rollers in action and ARVALIS-Institut du Végétal and the Chambers of Agriculture of Pays de la Loire offer a summary of rolling trials on frozen cover crops conducted from 2004 to 2006.

How to choose your roller?

Several factors must be considered:

Blade shape: straight or helical
Possibility to ballast the roller with water
Desired action on the plant: chop or pinch?
Date of cover destruction
Possibility to use it combined with the seeder

Indeed, the roller's action will depend on these criteria. Regarding blade shape, a cylinder on which helical blades are welded (type rolo-faca) will crush the cover (without mulching it), injure it, and thus stop sap flow in the plant, creating a mulch. Blades, straight or helical, arranged on a cylinder, will chop the cover, creating a mulch.

Regarding weight, the heavier the roller, the greater its impact on the cover. The helical shape of the blades allows concentrating the roller's weight for an enhanced effect.

Comparison of different rollers depending on the cover in place

The St Paul (Landes) CUMA conducted a comparison of equipment for destroying cover crops. The fdcuma 640 and Arvalis supported this trial for methodology.

To account for species diversity in a cover, organizers set up 12 different mixtures, with two or three species. All included a phacelia associated with a legume (field bean, pea, vetch, lupins), possibly complemented by a Chinese radish or dill.

The results below are given in percentage of effectiveness:


Type of cover	Tine cultivator with tines	Deep Disc harrow	Shallow disc harrow	Rotary harrow	Rolo faca
Field bean 200 kg/ha + Phacelia 3 kg/ha	78.3	97.0	91.7	93.3	92.3
Field bean 200 kg/ha + Phacelia 3 kg/ha + Dill 15 kg/ha	76.7	96.3	83.3	90.0	85.0
Field bean 200 kg/ha + Phacelia 3 kg/ha + Chinese radish 8 kg/ha	71.7	91.7	83.3	91.7	83.3
Forage pea 100 kg/ha + Phacelia 3 kg/ha	75.0	88.3	85.0	83.3	58.3
Forage pea 100 kg/ha + Phacelia 3 kg/ha + Dill 15 kg/ha	79.3	91.7	88.3	83.3	56.7
Forage pea 100 kg/ha + Phacelia 3 kg/ha + Chinese radish 8 kg/ha	78.3	85.0	86.7	86.7	55.0
Narbonne vetch 100 kg/ha + Phacelia 3 kg/ha	85.0	99.0	92.7	93.3	78.3
Early vetch (MARIANA variety) 60 kg/ha + Phacelia 3 kg/ha	71.7	81.7	66.7	81.7	35.0
Early vetch (SPIDO variety) 60 kg/ha + Phacelia 3kg/ha	70.0	78.3	60.0	80.0	21.7
Winter white lupin 50 kg/ha + Phacelia 3 kg/ha	75.0	80.0	73.3	91.7	48.3
Spring white lupin 50 kg/ha + Phacelia 3 kg/ha	81.7	95.3	88.3	91.0	41.7
Spring blue lupin 14 kg/ha + Phacelia 3 kg/ha	86.7	96.3	83.3	91.0	36.7

To read more about the conclusions of this comparison, click here!

To see other types of rollers, consult this page.

Details on the technique

The technique of rolling cover crops is most often combined with another technique (chemical, stubble cultivation, ploughing).

Implementation period: During the intercrop period

Spatial scale of implementation: Plot

Application of the technique

Crops: Easily generalizable.

Rollers will cause partial destruction of the cover.

Effectiveness depends on the species present in the cover: effective on species with tall stems: mustard, field bean, phacelia, Chinese radish, sunflower

Soils: Sometimes difficult to generalize.

This technique requires flat soil. Hydromorphic loamy soils should be avoided because laying the cover on this type of soil may slow and limit soil drying in spring. Rocky soils can hinder the use of chopper rollers (equipment wear).

Climatic contexts: Sometimes difficult to generalize.

This technique is suited to the following climates:

- Continental

- Oceanic

- Alpine

"Classic" rolling is only effective when it freezes, to increase the "injuries" inflicted on plants. The number of days available for this technique varies by region and year. Some winters may be too mild for this technique to be usable.

Regulations

No regulations govern the rolling of cover crops.

In vulnerable zone, the regional Nitrates Directive order may prohibit chemical destruction of covers. Rolling can be an alternative.

Services provided by the technique

Weed regulation and management

Rolling on covers injures plants and makes them more sensitive to climatic conditions, pests, and pathogens that will finish the destruction. Rolling alone may not be sufficient to prevent plant regrowth.

The effectiveness of rolling on weed flora depends on the type of roller used, which defines its aggressiveness and mode of action.

Effect level: LOW if technique used alone, to be combined.

Effects on cropping system sustainability

"Environmental" criteria

Effect on air quality: Increasing

Improvement of water quality due to reduced use of chemical cover destruction.

Effect on water quality: Increasing

Improvement of water quality due to reduced use of chemical cover destruction.

Effect on fossil resource consumption: No effect (neutral)

Compared to chemical cover destruction, rolling requires similar fuel consumption, which remains low (about 3 l/ha).

"Agronomic" criteria

Soil fertility: Variable

There is a risk of soil compaction depending on intervention conditions.

"Economic" criteria

Operational costs: Decreasing

No inputs used.

Mechanization costs: Increasing

Low cost technique but requires equipment investment. Fuel consumption is low (3 l/ha).

Margin: No effect (neutral)

Favored or disadvantaged organisms

Disadvantaged bioagressors


Organism	Impact of the technique	Type	Details
Mustard	STRONG	weeds	Rolling during frost is also effective on phacelia, buckwheat and field bean.
Vetch	MEDIUM	weeds	Rolling during frost is also moderately effective on Pea, Lentils and Radish.
Annual grasses	LOW	weeds	Ex: Oats, Rye
Italian ryegrass	LOW	weeds
Clover	LOW	weeds

For more information

Destroying your cover crops: a technical and economic challenge - Colette SUCHEL (CA Ain), Du Lien !, Professional report, 2017. Bio & Water program newsletter no. 34

Sheet n°2 Intermediate crops - Various authors from different organizations, IBIS, Technical brochure, 2009.

Guide on mechanical destruction of cover crops - CUMA Béarn - Landes - Pays Basque, Technical brochure.

The guide to cover crops in intercrop - CA Isère, Technical brochure, 2017.

Rollers, an additional tool to destroy covers - Jérôme Labreuche, Anne-Sophie Hervillard (ARVALIS-Institut du Végétal); Thierry Restif (CA44); Michel Chauvin (CA85); Jean-Philippe Rigaud (CA53); Jean-Claude Lebreton (CA53), Perspectives Agricoles, Press article, 2006.

Bonnel chopper roller - Nicolas FIGEAC - CUMA Charentes, CA17 TV, Multimedia, 2019.

Other videos exist on the Treffler chopper roller, the Roll'n'Sem crusher roller and the ActiSol chopper roller on the channel of the Chamber of Agriculture of Charente-Maritime.

Choosing the most appropriate cover destruction technique - Jérôme BRUN, Damien LABREUCHE, ARVALIS, Website, 2018.

Can we do without glyphosate? - Djilali Heddadj (CRAB), TERRA, Press article, 2012.

Rolling cover crops, a technique full of opportunities yet to be mastered - Matthieu Archambeaud, TCS n°64; September/October 2011, Non-peer-reviewed journal article, 2011.

Summary on Chopper Rollers - Olivier Guérin Chamber of Agriculture of Charente-Maritime, Professional report, 2019

Sources

Annexes

Contribue à

Weed regulation and management

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