Selenium concentrations in crops grown on low-selenium soils as affected by fly-ash amendment

Abstract

Studies were conducted under greenhouse and field conditions to evaluate the feasibility of using fly-ash amendments to produce selenium-adequate crops (0.10 to 0.30 ppm Se) on low-Se soils without adversely affecting either the crops or the soils. Two soils, a fine-loamy Alfisol belonging to the Honeoye series and a coarse-loamy Inceptisol belonging to the Mardin series were used to make 3 soil treatments thus: Honeoye, limed Mardin and unlimed Mardin. Fly-ash was mixed with the soils at rates of 0, 2500, 5000, 5000, 10000, 25000 and 50000 ppm. In the greenhouse studies the test crops were corn (Zea mays L.), alfalfa (Medicago sativa), birdsfoot trefoil (Loitus corniculatus) and dry beans (Phaseolus vulgaris L.). There were no yield differences due to fly-ash additions. The rates of 25,000 and 50,000 ppm fly-ash produced the desired Se levels in the utilizable parts of the crops. In the field studies, conducted on another fine-loamy Alfisol belonging to the Lima series and using fly-ash at the rates of 0, 11.2, 22.4 and 112.0 metric tons/ha, it was observed that the yields of corn and dry beans grown were also not influenced by the treatments. Increased levels of Se in corn grains (0.10 ppm) and stover (0.08 ppm) and dry bean seeds (0.14 ppm) were observed at the application rate of 112 metric tons per ha. The results indicate that fly-ash has a potential for producing forages and feed crops containing adequate amounts of Se to protect livestock from Se-responsive diseases.