Evaluation of beneficial use of wood-fired boiler ash on oat and bean growth

An evaluation on the effects of pulp and paper mill combined boiler ashes on growth and nutrient uptake by oat (Avena sativa L., var. 501) and bean (Phaseolus vulgaris L., var. blue pole) was conducted in a greenhouse. Asb with a calcium carbonate equivalent of 29.1% and a pH of 12.1 was applied at the rates 30, 40, and 50 dry Mg ha(-1) to Chehalis silty clay loam (fine-silty, mixed, mesic Cumulic Ultic Haploxerolls), with pH 5.4. An agricultural dolomitic lime treatment of 7.4 Mg ha(-1) and a nonamended control were also included. plants grown on ash-amended soil had higher biomass compared to plants grown on lime and control treatments. Ash treatments 30, 40, and 50 dry Mg ha(-1) increased the bean (stems and leaves) dry matter (DM) yield over the control by 49, 57, and 64%, respectively. The lime treatment increased the bean DM yield by 31% compared with the control. The asb rate 30 dry Mg ha(-1), equivalent to the recommended agronomic lime rate 7.4 Mg ha(-1), increased oat (shoots) DIM yields over the control by 45%, while the lime treatment increased biomass by 8% over control. The highest ash treatment, 50 Mg ha(-1), produced the lowest oat biomass. The asb was as effective as dolomitic lime in raising soil pH. Ash-amended soils contained higher concentrations of P, S, and B for plant growth compared to lime and nonamended soils. Soil Zn, Fe, Mn, and Cu concentrations decreased as asb application rates increased. Oat and bean plants grown in the ash-amended soil had increased concentrations of K, S, and B and decreased concentrations of Mn and Cu compared with plants grown in the nonamended control soil. Overall, oat and bean benefited from the increased nutrient availability and soil pH caused by the application of boiler ash.