Soil and alfalfa response after amelioration of subsoil acidity in a fine sandy loam Podzol in Prince Edward Island

Subsoils in Prince Edward Island have poor chemical and often physical quality for root growth that may present a barrier to development of alfalfa (Medicago sativa L.). This study was conducted to characterise the response or benefit, on soil properties and alfalfa growth, of chemical amelioration and loosening of the subsoil. In 1987, the following three treatments were imposed on an acidic, fine sandy loam, Humo-Ferric Podzol: control (no subsoiling or lime), subsoiling alone, and subsoiling plus lime (5 Mg ha −1 dry CaCO 3 ) mixed into the subsoil. The subsoiler was a Wye Double-Digger, a combined plough and rotary cultivator that facilitated the mixing of lime into the soil over the 230–480 mm depth. Management of the 0–200 mm soil depth was the same for all treatments. Growth of alfalfa and change in soil properties were monitored over time. In 2 of 4 yr (1991–1994), alfalfa yield was significantly (P