To determine the performance of crop establishment systems in both a replicated trial and on-farms, and the factors which impact upon the uptake of these systems by growers

To plough or not to plough, is an important consideration for most cereal growers. For these growers, there is a continuum of crop establishment systems available to choose from, which incorporate soil cultivation and sowing operations that vary in tillage type, depth, and intensity (Davies and Finney, 2002). In Ireland historically, plough-based crop establishment has dominated, but in recent years, there has been an increase in the interest and use of non-inversion (non-plough) systems to establish crops. Growers have turned to these systems to deal with reduced labour availability and increasing crop establishment costs as well as to retain soil carbon and increase work rates. Crop establishment systems research in drier climates frequently suggests that there are benefits associated with non-inversion systems (Triplett Jr. and Dick, 2008, Derpsch et al., 2010, Kassam et al., 2009, Soane et al., 2012, Zarea, 2011). However, the limited Irish research has indicated some concerns around the suitability of these systems in wetter climates such as; increases in critical grass weeds and herbicide-resistance development risk (Vijayarajan et al., 2022, Alwarnaidu Vijayarajan et al., 2021); inconsistent crop yields (Brennan et al., 2014); poorer crop establishment (Byrne et al., 2022, Brennan et al., 2014); and reduced suitability for spring cropping (Brennan et al., 2015). Crop establishment systems in addition to incorporating differences in tillage practice can include differences in residue management, rotation, cover cropping and traffic management. Researching these systems by means of conventional replicated field experiments is limiting, as it’s difficult to replicate the combination of treatments at a small plot level and to determine what aspect of the system may be contributing to any recorded differences. Many growers have suggested the need to monitor the performance of alternative non-inversion crop establishment systems at farm level, where previous history, field scale operations and individual management practice are all allowed influence the results. However, analysis of on-farm studies which are often un-replicated can be challenging. This thesis seeks to contribute to the identification and adoption of the most appropriate crop establishment system for use in wetter Atlantic-influenced climates and thus will present results from a research project examining: The crop, economic and environmental performance of first wheat crops established using different crop establishment systems in a replicated trial and on-farm study. Knowledge exchange and innovation adoption preferences of arable growers operating different crop establishment systems. Grower perceptions of technical performance of different crop establishment systems. To address the limitations of on-farm studies and of conventional replicated trials, the project incorporated both elements in studies carried out over three seasons (2020/21 to 2022/23), which addressed part of the first thesis objective. Data from these 2 studies was analysed to assess the impact of system on crop performance. To assess the impact of systems on the economic performance of the systems, a standard costing approach was employed to the data from these studies to estimate the margins net of input and machinery costs for each system. To address the second and third thesis objectives, a perception survey of growers operating different crop establishment systems was undertaken, this study consisted of 154 growers who managed 29,000 ha collectively. To assess the nvironmental performance of the different crop establishment systems, a biogeochemical model, DayCent, was calibrated using long term soil, yield and crop management data and the calibrated model was used to simulate the impact of the different systems and scenarios on soil organic carbon dynamics.