How can soil-improving cropping systems reduce compaction? Assessing mechanical methods in comparison to increasing root uptake and growth through biological amendments

Abstract

Maintaining soil health will reduce the negative spiral of degradation, increased inputs, increased costs and damage to the environment. Through discussions with stakeholders compaction was identified as a key area for investigation. An experiment was set up to understand how to alleviate or reduce the impact of compaction on crop yields. On a 0.36 ha area within an arable field the level of compaction was increased by multiple tractor movements perpendicular to tramlines to purposefully compact the area in a standardised way. The experiment was set up with four treatments and three replicates. Two mechanical method treatments were used to alleviate soil compaction directly - plough and a low disturbance subsoiler; and one biological, the addition of arbuscular mycorrhizal fungal inoculant at the time of drilling; as well as a no treatment control. Over one harvest year in which barley was grown, the change in compaction was monitored, along with the effect of treatments on greenhouse gas flux, soil physics, weed abundance and crop yield. There were significant differences between treatments in relation to the overall soil health and weed and yield abundance, however which treatments would be considered a soil-improving cropping system, needs further consideration.