This is how you choose your green fertilizers

The grain harvest will start early this year, so sowing of green manure crops is also on the way. The choice of crops and mixtures for green manures deserves just as much attention at plot level as that of the main crops. After all, there are major differences in rooting, mineral retention, organic matter production and nematode control or propagation.

How do you make the best choice from the wide range of green manures? Start from a primary cultivation goal per plot: with (possible) pressure from harmful nematodes, this is nematode suppression. And if harmful nematodes do not play a role, then you go for maximum organic matter and structure improvement.

Tip: On this page there is a handy filter with which you can choose your most suitable green manures.

Cultivation goal: suppress harmful nematodes
Know what is going on per plot and which nematode you want to control. Unfortunately, there is not 1 green manure that fights all harmful nematodes. Also be careful with mixtures: they can greatly increase populations of harmful nematodes, because they often contain 1 or more host plants. Studies show that even with 1 host plant in a mixture, the population grows strongly.

• beet cyst nematodes: multi-resistant fodder radish DOUBLET Plus gives the highest control of beet cyst nematodes (BCA1; more than 90% reduction), M. chitwoodi, fallax and hapla and the tobacco rattle virus. Fodder radish FINAL Plus is BCA-1. Avoid fodder radish and mustard varieties that are not resistant to beet cyst nematodes, clover, vetches, daikon (tillage) black radish, brown and Ethiopian mustard and buckwheat.
• Root knot nematodes: against M. chitwoodi and also M. fallax and M. hapla, DOUBLET Plus is the appropriate control agent. Also TERRANOVA Plus en NEMAREDUX fight root knot nematodes. Avoid yellow, brown and Ethiopian mustard, Italian ryegrass, Japanese oats, rye, clovers, vetches and buckwheat.
• Root lesion nematodes: patula tagetes gives an active kill of Praylenchus penetrans. Japanese oats is not worth and gives the same decrease as black fallow. Avoid radish, yellow mustard, legumes, Italian ryegrass and rye.
• Free-living nematodes: radish and yellow mustard give the lowest multiplication of free-living root nematodes. Avoid grass green manures.
• stem nematodes: Grass green manures give a low propagation of stem nematodes. Avoid yellow, brown and Ethiopian mustard, clover, vetch, alfalfa, buckwheat, nyger, deder.

Note: Nematodes actively search for their favorite green manure in a mixture!

Cultivation goal: supply organic matter and improve soil structure
On plots where there are no harmful nematodes, you go for maximum organic matter, intensive rooting and maximum mineral retention. Underground development is even more important than aboveground development: roots provide more effective organic matter and make the soil open, crumbly and airy.

• Japanese oats has a high success rate and produces the most effective organic matter (EOS). This green manure can be sown up to and including September.
• The mix ORGAMAX is specially formulated to deliver the highest possible organic matter at the lowest sowing costs (12 to 15 kilos per hectare).
• A successful grass green manure also provides a lot of organic matter.

Structural improvement
Each green manure improves the soil structure through rooting, but the extent to which differs per species. The picture shows the possible root development, but also pay attention to the growth period: radish has a large root package after 6 weeks, with alfalfa this naturally takes much longer.

View all recommended green fertilizers for 2018 here.

This business case is powered by: