Greenhouse study of slash pine response to fertilizer in a papermill-ash amended soil

Application of large quantities of papermill ash to soil increases soil pH and salinity, possibly leading to nutrient uptake problems. The effects of fertilizer application on plant nutrient uptake and biomass accumulation fo r papermill ash-amended soils were investigated. Two fertilizer regimes (co ntrol, NPK, and NPK + Fe/Mn/Cu) were used to study the responses of slash p ine, Pinus elliottii (L.), to two ash-application rates (control, 900 and 1 800 Mg ha(-1)) in the greenhouse. Slash pine trees were gown in vinyl pots from seedlings for 10 mo, harvested in three separate fractions (roots, ste ms and needles), dried, ground and digested for analyses of N, P, Ca, Mg, K , Cu, Mn, Fe and Zn. Concentrations of these elements were also determined for the soil. Soil pH, Ca, Mg, K, Na, and Mn were increased significantly i n the ash-amended soil. High ash application reduced aboveground biomass in the unfertilized pots by approximate to 40% and addition of fertilizer dec reased the reduction to only 15%. Papermill ash-amended pots did not show a ny response to K and Cu fertilizers due to the high concentrations of these elements in the ash, but plant uptake of Ca and Mg was enhanced. High-rate application of papermill ash adversely impacted pine tree growth (though n o mortalities were observed) but significantly increased overall plant nutr ient uptake except for Fc. Therefore, with proper fertilizer management, pi ne trees should still be able to grow on ash-amended soils. However, more t ypical agronomic rates are recommended if papermill ash is to be used as a soil amendment.