Cover crops an issue this spring
Published 27/01/2016 | 02:30
A new issue that looks likely to arise this spring is the amount of cover crops that are in the ground.
These crops have grown very well and some crops have huge covers established. While these crops contain huge amounts of nitrogen that potentially will be available to future crops, they will have to be managed carefully to avoid soil microbes using up all the available nitrogen during the breakdown of the material.
If it goes wrong, the breakdown of the cover crop will be like a bad dose of indigestion for the soil, where the microbes take up all the available nutrients in the soil and starve emerging commercial crops of fertility and a proper establishment. In this scenario, the cover crop is creating a severe disadvantage to the following crop, not an advantage.
To minimise this risk, the cover crops should be incorporated at the first opportunity in the spring, and chopped up very finely. Subsequent crop sowing should be delayed as much as practicable to give the microbes a chance to get their processes complete before the emerging crop calls upon soil reserves in which to grow.
Cover crops have the potential to make available more nutrients to spring sown crops than otherwise would be available, but the timing of this availability is crucial for successful implementation.