Longevity of liming in western Canada: Soil pH, crop yield and economics

In western Canada, approximately 2.0 million ha of cultivated soils are acid (pH ≤ 6.0), but liming of these acid soils is seldom practised because of its high cost. Liming increases yield of the most important crops (wheat, barley, canola and legumes), but long-term economic returns have not been measured until this report. Field experiments were initiated in 1965 at Chedderville, Alberta (0, 2.2, 4.4, 6.6, 8.8 and 11.0 t lime ha-1), in 1970 at Tomahawk, Alberta (0, 4.9 t lime ha-1) and in 1963 at Scott, Saskatchewan (0, 6.1 and 9.1 t lime ha-1). The original soil pH without lime was 5.4, 5.0 and 4.9 at Chedderville, Tomahawk and Scott, respectively. The test crops were alfalfa, barley and wheat. Single application of lime maintained increased soil pH and crop yield for 16 to 27 years. Crop yield increases from single applications of lime were similar with the years. Economic value of increased crop yield from lime was substantial at all sites. Because of this long-lasting effect, the cost of applying lime to an acid soil should not be considered a normal production cost, but rather a capital investment amortised over a long period.