Field investigation of a trash-board, tillage depth and low speed effect on the displacement and burial of straw

• Trash-board with mold board plow reduced soil displacement with negligible effect on straw displacement.
• Presence of a trash board led to higher straw burial performance.
• The longer straws were less effective to be incorporated into the soil than shorter.
• Lower speeds resulted in larger soil fragments and straw displacement with more straw buried.
• A trashboard was always creating fragmentation larger than without a trashboard.

A minimum amount of straw is still needed to protect soil from wind and water erosion. To better understand the soil protection effect of straw, the relation of wheat straw displacement and its burial status with plowing speed, tillage depth and the attachment of trash-board was studied. Three controlling factors were evaluated in a field tillage testing, i.e., two types of plow (with and without trash-board), three lengths of straw (100 mm, 150 mm, and 250 mm), and various straw conditions. Straw pieces with specific lengths were prepared before the experiment and used as point tracers to measure the soil and straw displacement. The results indicated that the soil and straw displacements were significantly different but that the two were interrelated. As the length of straw increased, the soil displacement decreased due to the forward and lateral displacements; the straw displacement was always significantly larger than soil displacement, independent of the straw mixtures. Attachment of a trash-board reduced the soil displacement, but had no apparent effect on the straw displacement. Longer straws were less effective to be incorporated into the soil than the shorter ones, and the presence of a trash-board led to higher straw burial performance. The results also indicated that low tillage speed resulted in larger soil fragments and straw displacement with more straw buried. Moreover, longer straw was less effectively buried than shorter straw at the same speed. However, straws neighboring the shear were more extensively displaced than those nearby the share bottom.