Reduced tillage improves energy efficiency in winter sown combinable crops

NIAB TAG’s New Farming Systems (NFS) research programme, currently in year nine and based at Morley in Norfolk, consists of several long-term field trials aiming to develop bio-sustainable cropping systems for conventional arable cropping. A component of the trials is evaluating the impact on energy efficiency of reduced or non-inversion tillage, a technique that has been cited by a number of previous studies as a potential means to improve the efficiency and resilience of arable cropping. Plough-based systems, used traditionally in arable cropping, in which soil is inverted with a mouldboard plough, are compared with non-inversion alternatives. These are either shallow (5-10 cm) with crop residues remaining mostly on the soil surface, or deep (15-20 cm) where a proportion of residues are incorporated into the topsoil. Soil compaction, a potential risk associated with reduced cultivations, is removed with a subsoiler. Although non-inversion tillage is reported to be advantageous due to decreased operational time and decreased energy input per ha, the effect on crop yield and impact on energy consumption per t of crop output needs accounting for. Previous work undertaken at NIAB TAG had shown an initial decrease in crop yield immediately after conversion to a noninversion tillage system and then a yield that then increases in following seasons, although it is unclear if this was a trend or associated with responses to specific seasonal conditions. However, a key question to address is whether this yield reduction reduces energy efficiency, and if so, in which crops and what are the longer term rotational implications.