Growth, Photosynthesis, and Water Relations of Wheat Grown on Acid Soil Amended with Coal Combustion By-Products

Aluminum toxicity often reduces plant growth on acid soils, and coal combustion by-product (CCBPs) can partially mitigate acid soil effects. Columns containing acidic (pH 4.7) Lily soil (Typic Hapludult) were amended in the upper 15 cm with CCBPs, lime, or both. Amendments were, in grams per kilogram, (i) none (Check); (ii) 3.98 dolomitic limestone (Lime); (iii) 15.88 high-gypsum flue gas desulfurization by product (FGD); (iv) 3.98 + 15.88 combination of Lime + FGD; (v) 15.88 high-gypsum FGD by-product containing −6% Mg(OH)₂ (FGD + Mg); and (vi) 6.45 fluidized bed combustion by-product (FBC). The soil columns were leached with 138 cm of deionized water. Wheat (Triticum aestivum L., ‘Arthur’) was grown in the columns for 34 d with no additional water. Plants grown in Check and FGD treatments had lowest and similar shoot and root dry matter (DM) and leaf area. Leaf areas and DM for FBC, FGD + Mg, Lime, and Lime + FGD plants were similar and 13 to 17 times higher than for Check plants. Total root length (RL) was highest for FBC plants, which was about six-fold higher than FGD plants, while total RL of plants grown with other amendments was about half that of FBC plants. Specific RL was highest for FGD plants. Plants grown on Lime, Lime + FGD, FGD + Mg, and FBC treatments had higher leaf photosynthetic rates, chlorophyll, and ET and lower leaf temperatures than Check and FGD plants. Even though DM of FGD plants was low, they had the highest leaf relative water content (RWC) and leaf water potential (LWP). Amendments increased soil pH and reduced acid soil stress. Higher mineral nutrient concentrations were noted in shoots of plants grown on amended soil, except for the FGD plants, which had lower Mg and higher B than considered optimal. Some but not all CCBPs benefitted plants grown on acid soil. This research was conducted under a collaborative agreement between Virginia Polytechnic Institute and State Univ. and USDA-ARS at the Appalachian Soil and Water Conservation Research Laboratory, Beckley, WV, under cooperative agreement number 58-1932-2-036.