To plough or not to plough?

Growers’ perceptions and results from trials looking at different crop establishment systems in commercial grower's fields and in replicated experiments will be on display at this year's Crops and Cover Crop Cultivations event in Teagasc Oak Park on Wednesday, June 21st.

A survey spanning 154 growers and almost 29,000ha was undertaken in late 2021 to learn what growers’ perceptions about min-till and direct drill crop establishment systems were, in comparison to a plough-based system. It also determined from where growers got their information and how they accessed that information for various types of decisions, such as changing crop establishment system.

This information is essential to improve knowledge transfer to growers and to see if growers’ perceptions are supported by relevant research and to identify knowledge gaps where they are not. Growers’ average cropping area was 187ha, with equal number of plough, and non-plough based growers participating.

In the below video, Jack Jameson, a Walsh Scholar PhD student, outlines his work at Oak Park and on farms that addresses key questions about the performance of these systems.

The perception survey contained over 90 questions and yielded valuable insights from growers, many of which will be shared at the open day.

As an example there were some cover crops questions in our survey, as many growers consider them an integral part of non-plough crop establishment systems, with many potential benefits if managed correctly.

• The majority of growers thought that there would be an increase in cereal yields of up to 10% after five years of legume or non-legume cover cropping. However, the evidence to support this in our conditions is not strong. Research conducted by Richie Hackett in Oak Park would suggest that whilst in some years there can be a benefit to the subsequent cereal crop from cover cropping, this is usually only associated with legumes, as an N substitution effect. And, even with these crops, the responses  are inconsistent; consequently, it is currently difficult to advise growers to reduce their nitrogen rates after cover crops.  
• Most growers thought that cover cropping for five years would increase soil organic matter (SOM) levels; with over half of all growers thinking that SOM levels would increase by more than 10% after five years. Whilst any addition of crop biomass will tend to contribute to the soil carbon pool, research would suggest that those additions are quite small, and assuming stable soil carbon levels in the background, over five years, cover cropping with consistently high cover crop yields, may add about 1.4% extra to the existing carbon pool.

This work is part of a PhD programme and the questionnaire complements the field research components of the entire project, which compares plough, min-till and direct drill establishment systems in: 1) long-term replicated field trials in Knockbeg, Co. Laois and; 2) in-field trials involving 21 commercial growers (seven of each system) across three seasons, totalling 63 fields. In both of these trials, we are monitoring crops of first wheat and investigating crop, economic and environmental performance. These trials will conclude this season and the outputs will be shared thereafter.

Some results of the first two seasons of these field trials will be on display at the open day, so come to the Crops and Cover Crop Cultivations event at Oak Park on June 21^st to learn more.