Tillage & undersowing effects on organic wheat yield components & yield
- The study ran from October 2010 to August 2012, with winter wheat cv. Claire sown in November 2010, plots undersown in April 2011, and spring wheat cv. Paragon sown in March 2012 and undersown in April.
- Differences in plant height, ear numbers, grain yield, legume dry matter, and weed dry matter (DM) were all recorded.
- Greater plant heights and ears per m2 were recorded for winter wheat with CT & LRNiT when compared to HRNiT. This was attributed to better seedbed quality and reduced weeds. It indicated that LRNiT could be a viable alternative to CT.
- For the spring wheat crops, CT produced higher grain yields than LRNiT or HRNiT.
- Non-inversion tillage often has a greater variability in seedbed than CT, which can cause slower plant growth and shorter plant heights.
(Image shows direct drilled organic wheat on the left and plough power harrow drilled on the right; showing the large grass weed burden that has accumulated under a direct drill senario)
- Undersowing black medic did not suppress weeds, and may have even resulted in greater weed DM. This caused greater competitiveness and a significant lowering of yield compared to non-undersown.
- Undersowing white clover did not significantly reduce the wheat yield (having less negative influence, and strong competitiveness with weeds). It therefore proved to be more suitable with spring wheat.
(Image shows direct drilled wheat undersown with medium leaf white clover but struggling with a large grass weed burden)
(Header image: Minimum tillage established spring wheat on the left and plough power harrow established spring wheat on the right, 2012. All photo credits: RAU)