04 June 2025

Spreading the risk in organic tillage systems

Farming without pesticides, fungicides or chemical fertilisers, organic tillage farmers were reminded of the importance of establishing effective crop rotations to improve the resilience of their farming systems to weather, disease and pest challenges.

Speaking as part of a Teagasc Organic Farm Walk on the farm of Rod and Julie Calder-Potts, Highbank Farm, Cuffesgrange, Kilkenny on May 29, Teagasc Organic Tillage Specialist, Martin Bourke delved further into the benefits of effective crop rotations.

In organic systems where chemical controls are limited, Martin Bourke explained, farmers need to think ahead of the potential risks – whether disease or weeds – and implement strategies in the form of crop rotations to overcome these.

For example, where spring crops are continuously sown, the opportunity for weed control may become limited. Primarily occurring as many of the tillage weeds associated with organic farming are spring germinating, Martin Bourke noted that adding a winter crop into the rotation mix offers the opportunity to control weeds.

“Winter crops establish earlier and create a canopy that suppresses weed growth, reducing weed pressure naturally,” Martin Bourke explained.

Altering the cropping mix between spring and winter sown crops adds extra resilience to the system.

“In difficult springs, winter cereals tend to perform better, while in other years, spring crops may have the advantage. This helps organic farmers mitigate risk across seasons and years.”

Diversity in crop rotations also supports better disease control and soil health. One such benefit is being able to establish cover crops early after winter crops – allowing for greater soil nitrogen capture and the incorporation of organic matter back into the soil when establishing subsequent crops.

Winter oats

Speaking from Highbank Farm, where Rod and Julie Calder-Potts had established a winter crop of organic oats after a fallow break, Martin Bourke also reminded farmers of the risk of oat mosaic virus.

“Oat mosaic virus can build up in the soil if winter oats are grown continuously. Unlike spring oats, which generally do not allow for virus replication unless spring oat volunteers persist uncontrolled over winter, winter oats can significantly increase the risk of infection.”

“Historical outbreaks in the 1980s and 1990s resulted in fields being unsuitable for oat cultivation for up 15-20 years. To avoid repeating such scenarios, growers need to carefully consider their crop rotations and avoid consecutive planting of winter oats without appropriate breaks,” Martin Bourke added.

The series of Teagasc Organic Tillage Crop Walks continue this week, find out more here.