Grazing plant cover

Management of fodder resources, grazing time, composition of plant cover, food self-sufficiency.

Grazing plant coverManagement of fodder resources, grazing time, composition of plant cover, food self-sufficiency.

1. Mixed farming
2. Grazing plant cover

Weed control by grazing animals

In field crops, intercroppingplant cover refers to all plants that cover the soil between two main crops in the rotation. They may be planted after harvest or consist of regrowth, and are most often intended to protect the soil from water and air erosion or toprevent nitrate leaching during the peak mineralisation period in autumn.

In some polyculture-livestock systems, the establishment of these cover crops can be considered in relation to thefeeding of the herd : in this case they are exported from the system (rather than returned) and are then more generally referred to as catch crops. This page sets out the main ways in which these crops can be grazed.

General principles

In addition to the benefits for soil fertility set out above, grazing plant cover crops can be used to supplement the green feed ration of animals when fodder resources become limited. A cover crop following a spring crop (harvested in summer) can be grazed by ruminants in autumn or even winter, when there is less grass in the meadows.. Conversely, in the case of cover crops following winter crops, or in certain permanent cover systems, grazing the cover crops helps toweaken them before they are destroyed, thereby reducing the use of herbicides and making it easier to use tools.

From an environmental point of view, this practice is judged to have no significant impact on nitrate leaching (compared with an ICNAF cover returned to the soil). There are, however, points of vigilance to be taken into account to avoid overgrazing or excessive trampling of the plot, it is recommended to respect the limit of 0.8 LU / ha.

To sum up : grazing intercropping cover crops can make it easier to destroy them, while at the same time providing organic recovery through manure, as well as a rich, diversified diet by delaying the use of winter fodder stocks. This technique is therefore relatively economical, but can involve labour time associated with fencing and moving fences.

Composition of cover crops

If cover crops are to be used to provide an alternative source of feed for livestock, their composition needs to be considered in terms of various parameters :

• The nutritional value( s) of the species(s) planted : estimate the various indicators (UFL, PDI, etc.) to see whether and to what extent the ration needs to be supplemented.
• Biomass establishment and production capacity, depending on the season, soil type, previous crop, etc.
• The digestibility of the species : avoid certain protein crops, such as alfalfa, which are too meteoric.
• Possible allelopathic or anti-parasitic effects can be sought (e.g. : plants with anthelmintic properties due to their concentration of tannins, etc.).)

Depending on needs and objectives, the cover can be diversified or mono-specific and planted or made up of regrowth. The use of several species such as sorghum, clover, ray grass, forage rape, etc. is recommended.

Other forage cover crops

Intercropping forage cover crops are not always grazed; they can also be stored as silage or wraps to supplement the herd's ration, or used as green fodder. This is particularly the case with forage sorghum and cabbage, or combinations of Poaceae( Italianryegrass, moha, Brazilian oats, etc.) and Fabaceae(red clover, vetch, etc.).