Agricultural lime reaction and retention in a diversity of soils under continuous centrifugation

Abstract Agricultural lime is an important natural resource for changing soil pH values. Annual lime applications in the UK have fallen for decades. Estimating soil factors that contribute to the retention and losses of lime would be useful for farmers making resource decisions. The aim of this research was to analyse the soil factors contributing to leaching loss and retention of agricultural lime in Scottish grassland soils. This research also tested the applicability of a large centrifuge method for measuring leached solutions from soil, suggested as an alternative to leaching columns. The soils studied in this research were highly variable in their response to lime. Measures of soil exchange capacity (cation exchange capacity, lime buffering capacity and organic matter) and clay content were highly associated factors to calcium loss and retention within a soil. Suggestions to farmers include consideration of soil clay content, organic matter content (as expressed through C) and cation exchange capacity as factors in lime decision making. Higher exchange capacity soils lost more calcium, likely due to the greater liming requirement of these soils and potential increased excess calcium applied. It is suggested that methods for improving calcium exchange and soil uptake be explored for improving lime retention after liming events.