Reviewing lime applications for acidic sands: Products, rates and incorporation techniques

Trial 1: Lime comparison trialThe use of new pH mapping technologies has increased the awareness and identification of soil acidity in many districts. However, there are several aspects of soil acidity management which remain a problem for growers. This trial aimed to investigate a range of lime and acidity management factors outlined in the three key areas below.Lime sourceLime rate and particle sizeDecline of soil pH from sulphur applicationsTrial 2: Comparison of lime incorporation techniquesAcidic layers of soil are increasingly being identified in the topsoil (0-10 cm) and subsurface soil (10-30 cm) of no-till farming systems. Stratified low pH soil layers need appropriate lime treatment to maintain and prevent the decline of soil pH further. Surface application of lime alone is unlikely to raise the pH in subsurface layers quickly. Recent work has reported lime movement as little as 1 cm – 2.5 cm per year (Fleming et al. 2020, Burns et al 2017). Given the slow movement of lime, incorporation and mixing of surface applied lime to depth is expected to accelerate the movement of lime.There are a range of machinery options that can provide different levels of lime incorporation and to different depths, such as cultivation, deep ripping with or without inclusion plates, spading and combinations of these. This trial was designed to investigate which of these are most effective on a sandy soil with stratified soil acidity at Bute.