How tine characteristics of subsoilers affect fuel consumption, penetration resistance and potato yield of a sandy loam soil

Abstract

Subsoil compaction has become a widespread problem for modern agriculture. Subsoiling is the most common measure to try and deal with this problem. However, despite the widespread use of this type of deep tillage, its effectiveness and sustainability are not without dispute. Previous studies show a great variety of outcomes depending on soil texture, soil moisture content, weather conditions and subsequent field operations, but the effects of the wide variety in available subsoilers have remained understudied. This study evaluated the effectiveness and sustainability of three different subsoilers on a sandy loam soil with a highly compacted upper-subsoil. The tested subsoilers differed in the number of tines, and thus the spacing between them, and several other tine characteristics, like the width of the tine foot and the curvature of the tine. The choice of subsoiler showed a clear impact on soil disruption, fuel consumption and mechanical resistance after one year. Limiting subsoil disturbance by using a subsoiler with less tines seems to have the potential of slowing down recompaction, measured indirectly via penetration resistance, in the upper-subsoil. This would help reduce the frequency of subsoiling, which clearly is a high cost field operation. This experiment highlighted the importance of not over-expanding the working depth of the subsoiler. Not all available subsoilers will be able to disrupt the subsoil down to depths where compaction can regularly be found in Europe and even relatively powerful tractors will be pushed to their limits during these deep tillage operations. Even when effectively breaking open the compacted subsoil layer, no significant effects on potato (Solanum tuberosum L.) yield were observed. Most likely linked to the rather wet conditions prevailing during the tuber bulking period, reducing the potential benefit of opening up the subsoil to root exploration.