Shallow ploughing did not negatively affect yield and rotation offered average yield benefits of 19% to the following wheat crop in systems research carried out by Teagasc.
Speaking at the Teagasc national tillage conference, Dermot Forristal compared continuous winter wheat with crops in rotation.
Rotation benefited the next cereal by an average of 19% over six years, but this benefit ranged between 3% and 41%.
The rotation in the trial consisted of all winter crops – oilseed rape, wheat, oats, wheat and barley.
Dermot said the average benefit to margin between continuous winter wheat and first wheats was €208/ha (45%) from 2015 to 2020 .
These results came from a research project which started in 2014 looking at crop rotation and establishment systems. The site had been in min-till v plough since 2001.
Commenting on the establishment systems, Dermot noted there was little difference in crop yields between plough (225mm or 9in), shallow plough (<150mm) and min-till (75mm) systems.
However, strip till (<150mm depth with 330mm row spacings) yields did often carry a small yield penalty, according to Dermot.
The savings in establishment costs may make up for the loss
Noting no significant difference between plough and shallow plough, he added: “You’d have to ask the question, why are we ploughing deeper than that?”
Examining the yield of different crops in the four establishment systems, Dermot noted that crop type matters.
Winter oats performed well with strip till, but yield from the other crops were somewhat lower, especially from barely.
The savings in establishment costs may make up for the loss.
Grass weed issues were a concern in the strip-till plots, but Dermot acknowledged that management changes such as reduced spacings may decrease risk.
However, reduced tillage carries a higher grass weed risk than ploughing and while rotation can reduce this risk, it is important not to rely on herbicides in the rotation.
Overall, the benefits of rotation to soil health, structure and input reduction can help to improve sustainability on the farm, while reduced depth of tillage and passes of the tractor will also work to overcome emissions from soil and fuel, while contributing to soil health.
Direct drilling has now been introduced at the site and the inclusion of cover crops is being examined.