The effect of cultivation method on optimum plant population in winter wheat

Abstract

This project aimed to understand the impact of reduced tillage on crop establishment and optimum plant population, by understanding how cultivation practice may limit the crop's ability to compensate for low plant populations.  An additional aim was to produce quantitative data on factors affecting plant establishment.

In experiments, at three sites with differing soil types, over three years, we examined the interactions between five seed rates (40, 80, 160, 320 and 640 seeds/m²) and three cultivation treatments using farm-scale equipment. The three cultivation treatments were: ploughing, reduced tillage and reduced tillage plus an application of nitrogen (30-40 kg/ha) between drilling and emergence to remove any effect of differences between treatments in residual nitrogen.

• Conclusions
  Cultivation practice had a significant effect on seedbed quality and resultant plant establishment.
• On unstable silt-dominated soils, plough-based cultivation practice resulted in better seedbed structure, greater plant establishment (54% more plants) and greater crop growth (45-48% higher spring green area index and dry matter yield).
• On stable soils, reduced tillage cultivation practice resulted in significantly better seedbed quality, greater plant establishment (21-24% more plants) and greater crop growth (22-24% higher spring dry matter yield and 16% more green area index).
• Cultivation practice did not limit tillering compensation for low plant densities.
• Cultivation practice had a significant effect on grain yield through effects on seedbed structure or quality, resulting in improved levels of plant establishment.