FIGURE 5.

Effects of tillage treatment and residue regimes on the inoculum potential (IP) of F. graminearum and F. avenaceum in two experimental fields of oats in southeast Norway (Solør and Østfold) in 2011 and 2012. Tillage treatments include DAP, deep autumn plowing; SSP, shallow spring plowing; SAH, shallow autumn harrowing; SSH, shallow spring harrowing. Data from the two residue regimes examined are indicated by either hatched bars, where the straw was removed, or filled bars, where the straw was chopped and retained in the field. IP was calculated as the relative soil area covered with oat residues after sowing in spring (0–1) multiplied by the percentage of the residues infested with the respective Fusarium species. Different letters indicate significant treatments effects at p = 0.05.