Concept:
Furrow openers are used in seed drills and planters to open a furrow in the soil for seed placement.
Step 1: Different types of furrow openers are used according to soil condition and seedbed preparation.
Step 2: Trashy soils contain residues and may not have a smooth seedbed.
Step 3: In such conditions, the opener should move through the soil and residues without excessive blockage.
Step 4: Shoe type furrow openers work well in trashy soils and rough seedbeds.
Step 5: Therefore, the correct answer is shoe type.
\[
\boxed{\text{Shoe type}}
\]