Planning of the rotation
A good rotation prevents the build up of plant pathogens and weeds by disrupting their life cycles through different growth habits, planting dates and control methods whether chemical or mechanical. It can also introduce fertility into the rotation either by fixing or mining nutrients or by allowing cover crops to be grown which can be incorporated or grazed by livestock. It can introduce diversity in rooting depth, planting date and harvesting date. Each crop has its own function in the rotation. Which crops are best chosen depends on many factors. Some examples are given below for inspiration.
Description of the method
A good rotation will involve nutrient harvesting crops being followed by nutrient needing crops-pulses followed by vegetables. Ideally, there should be a different species of crop each year so pest and diseases do not build up, and changing from spring to winter sown crops prevents weeds and pests building up. Crops requiring deep or fine seed beds (such as vegetables) should be followed by deep rooting crops to repair soil damage and harvest unused nutrients. An example would be (1) winter sown wheat, (2) winter sown barley, (3) cover crop followed by spring sown beans(or potatoes) (4) winter wheat, (5)Winter cover crop followed by spring sown barley, (6) OSR (Oilseed Rape) and then the rotation starts again. Each break crop followed by a wheat crop and cover crops used wherever possible.
Example for diary farmers
Maize and grass are often important parts of a dairy farmers system. Both are good break crops within the arable rotation and a rotation of ryegrass, wheat, maize, wheat, ryegrass uses the cereals to produce grain and straw, reduce pollution risk and provide a ground cover over winter. A grazeable cover crop over winter before maize, or ryegrass sown into growing maize crop can also reduces pollution risk.
Ryegrass sown into growing maize crop can reduce pollution risk of nitrogen (Picture: Hooibeekhoeve)
How to evaluate a new rotation?
Assessment tools
Whithin the project DiverIMPACTS a toolbox was made for crop diversification. Already existing tools and resources provide support on a range of topics related to crop diversification. Such tools and resources have been gathered by the DiverIMPACTS partners into a database. The objective of the DiverIMPACTS toolbox is to help you identify relevant resources or tools among this database to support you in fostering crop diversification. The toolbox is based on an aggregative program (DEXi model) which compares your needs to the content of the database.
The toolbox is available here (scroll down at the page) (English and French).
Special requirements
Each crop requires its own techniques. Before you start, make sure that you have looked at the whole picture in function of the material (seed bed preparation, weed and pest control, harvest...).