Lime loss rates from arable and grassland soils

Abstract

Lime loss rates were determined for 11 agricultural soils across England (1987–92) under arable cropping (six sites) and grassland management (five sites), receiving commercial rates of fertilizer inputs. Lime additions in the range 0–1500 kg ha⁻¹ CaCO₃ (250 kg ha⁻¹ CaCO₃ increments) were made annually to the sites. Soil pH (water and 0·01 m CaCl₂) and exchangeable calcium concentrations were measured annually. The annual lime loss rates were calculated as the amount of lime needed to maintain the initial site pH or exchangeable Ca concentrations.

Lime loss rates based on soil water pH varied between 40 and 1270 kg ha⁻¹ CaCO₃, on the basis of CaCl₂ pH between 0 and 1370 kg ha⁻¹ CaCO₃, and exchangeable Ca between 0 and 1540 kg ha⁻¹ CaCO₃. There was a positive relationship between the lime loss rate (based on water pH) and initial soil pH value (r=0·75; P<0·01), and a negative relationship with soil organic matter content (r=0·63; P<0·05) was based on soil pH, organic matter content and nitrogen (N) fertilizer input. Lime loss rates were approximately double those predicted by previous models developed in the 1970s, reflecting the greater quantities of inorganic N fertilizer now being applied to agricultural land.