Conservation Agriculture Using Coulters: Effects of Crop Residue on Working Performance

Conservation agriculture is an important measure promoting sustainable agriculture in northeast China. Coulters in the conservation agriculture system are used to cut the excessive residue in strips, loosen soils, and create good seedbeds. Information on the performance of coulters worked in a field with or without corn residue coverage is lacking in the literature. In this study, five coulters were tested in two field conditions at three working velocities to compare their performance. The five coulters were four types of fluted coulters (8 W, 13 W, 18 W, and 25 W) and one notched-flat coulter (NF); the two field conditions were whole residue plots (WR) and no residue plots(NR), and the three working velocities were 8 km/h (V1), 10 km/h (V2), and 12 km/h (V3). All of the tests were tested at a tillage depth of 80 mm. The results showed that the maximum furrow width (W<inf>f</inf>), furrow disturbance area (A), and residue coverage change (C) were significantly affected by the working velocity and coulter type, while the cutting force (F) and skid rate (S) were significantly affected by the residue coverage, working velocity, and coulter type. The NF was found to have the smallest furrow profile, residue coverage change, and cutting force, as well as the largest skid rate. Among the fluted coulters, as the wavenumber rose, the cutting force, furrow width, and furrow disturbance area all gradually decreased, while the skid rate and residue coverage change were gradually enhanced. The straw residual intensified the cutting force and reduced the skid rate, which changed by 11.6% and 20.9%, respectively. As the working velocity rose from 8 km/h to 12 km/h, the furrow width, furrow disturbance area, residue coverage change, cutting force, and skid rate increased by 26.5%, 16.5%, 44.6%, 8.2%, and 22.7%, respectively. The results reveal that the flat coulter and large-wavenumber fluted coulters (18 W and 25 W) have less cutting force and are more beneficial for cutting straw residue in residue coverage fields, while the small-wavenumber fluted coulters (8 W and 13 W) are suitable for loosening soil and constructing seedbeds. The cutting force has significant effects on the performance of cutting straw residue, loosening soils, and creating seedbeds.