Short-term effects of vertical hole drilling using a novel semi-autonomous machine on maize yield and soil physical properties in a Cambisol sandy soil

Abstract

Soil compaction negatively impacts crop yield and soil health, posing a serious threat to the environment and agriculture sustainability. The amelioration of subsoil compaction mainly by subsoiling remains a costly and labor-intensive task that necessitates intelligent automation solutions. The aim of this study is to evaluate the effects of drilling vertical hallow cylinders (40 mm in diameter) on subsoil compaction amelioration and fodder maize (Zea mays) yield in a Cambisol, sandy-textured soil over two subsequent cropping seasons. Six treatments with three replicates were tested in plots of 9 m by 9 m area, which were randomly distributed across a field in Flanders, Belgium. These treatments differ in depth (D) and hole-to-hole spacing (S), along with a no drilling control treatment (T0). Treatments consist of T1 (50 cm D by 50 cm S); T2 (50D by 75S); T3 (50D by 100S); T4 (90D by 50S); T5 (90D by 75S); and T6 (90D by 100S). Results showed that while minor improvement in soil compaction and crop yield took place in the first year of drilling after crop harvest, improvements were significant in the second cropping season. The highest yield increases with descending orders were observed in T6 (12.4 %), T5 (7.6 %), T4 (6.8 %) and T3 (1.7 %), compared to T0 treatment. At the second cropping season, BD at 40 cm depth decreased significantly in T3 by 7.5 %, while at 70 cm depth, BD decreased also significantly by 6.2 %, 8.6 %, and 7.4 % in T4, T5, and T6, respectively. These findings suggest that all the treatments with 90 cm depth penetration showed significant decreases in BD and significant increases in yield, with 75 cm and 100 cm spacing providing the highest increases in the yield. Further research is needed to determine the optimal depth and spacing for different crops and soil types.