Soybean Growth and Boron Distribution in a Sandy Soil Amended with Scrubber Sludge
- L. S. Ransome and
- R. H. Dowdy
A field study was conducted to determine the feasibility of using scrubber sludge residues from coal-fired generation of electricity as an agricultural soil amendment. Boron distribution between plant, soil, and soil water was monitored to determine whether scrubber sludge application would enhance crop growth by alleviation of the B-deficient status of an irrigated Hubbard loamy sand (Udorthentic Haploborolls) without elevation of soil or soil-water B to phytotoxic levels. Soybean (Glycine max L.) plants were grown on plots amended with 0, 10, 20, and 40 Mg scrubber sludge ha−1. Effects on plant populations, bean yield and nutrient content, B availability, soil-water B concentration, and electrical conductivity (EC) were measured for three growing seasons. Hot-water extractable soil B was elevated from low (0.40 mg kg−1) to sufficiency levels (> 1.0 mg kg−1) by application of at least 20 Mg scrubber sludge ha−1; such levels were maintained for two to three growing seasons. Soil-water EC and B concentrations reached levels potentially detrimental to soybean production during the application year at the 40 Mg ha−1 rate. Elevated soil-water EC and B levels were mediated after the first growing season as leaching removed excess soluble components from the root zone. Soybean populations decreased linearly with increasing rates of application the first two growing seasons following application. Yield was significantly reduced the first year but was enhanced in response to scrubber sludge application the third growing season. Leaf B content was significantly increased all 3 yr; symptoms of B toxicity were visible only during the year of application. Seed B, although significantly affected by treatment, did not parallel leaf B or yield.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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