Comparative Effects of Wood Ash with Lime and Dairy Manure On Soil and Crop Productivity.

Comparative effects of wood ash with lime and dairy manure on soil and crop productivity

Tarlok S. Sahota

Both manure and wood ash can supply essential nutrients, but only wood ash and lime can ameliorate soil acidity. Two field experiments were conducted at Thunder Bay, Ontario, during 2004 – 2009 to study the comparative effects of wood ash and lime at different frequencies of application and wood ash and manure on soil fertility and crops (alfalfa and barley) productivity. Lime and wood ash were applied at the recommended rates in 2004 and @ 4 t ha^-1 and 10 t ha^-1, respectively, thereafter every 2 or 4 years. In the wood ash and manure experiment, solid dairy manure was applied @ 50 t ha^-1 every 2 years; wood ash was applied at recommended rate in 2004 and @ 10 t ha^-1 thereafter every 2 years. Both lime and wood ash increased soil pH from 5.9 to neutral. Wood ash improved availability of P, K, Zn, Mn and B more than lime; reverse was true for available Ca. Wood ash improved soil organic matter more than lime. Increase in total productivity (alfalfa + barley) was 0.4 t ha^-1 yr^-1 with lime and 1.0 t ha^-1 yr^-1 with wood ash. Application of wood ash increased protein content in first cut alfalfa by ~2 % points and lime only by 1 % point as compared to check. Application of lime every 2 years, had an adverse effect on crop productivity. This could be overcome by combined application of lime and wood ash (each at half the rates). Lime/or wood ash did not increase heavy metals content in the soil. Manure marginally increased soil pH; wood ash raised the pH from 5.9 to 7.2. Wood ash increased available Ca, Zn, Mn and B more than manure, whereas, reverse was true for available K and Mg. Build up of soil organic matter was little better with manure than with wood ash. Total crop productivity was in the order of wood ash + manure ≥ wood ash ≥ manure > check (no manure or wood ash application). Application of manure/or wood ash improved first cut alfalfa protein content by nearly 2 % points as compared to the check. Application of the two together further raised the protein content by ~1 % point.