Crop response to soil applications of phosphogypsum
Phosphogypsum (PG), a by-product of the phosphate industry, was incorporated with soil to determine effects of land disposal on crop growth and uptake of cadmium (Cd) and radium (Ra). Application rates of PG were 0, 22, and 112 Mg ha/sup -1/. Soil was cropped sequentially with corn (Zea mays L.), wheat (Triticum aestivum L.), and soybeans (Glycine max (L.) Merr.) over a 1-5-yr period. Yields of corn were decreased at the high PG rate, apparently because of a physiological calcium-magnesium (Ca-Mg) imbalance, but yields of wheat and soybeans were not affected by PG application. Concentrations of nutrient elements and Cd in the grain of each crop were not affected by PG application; the Cd concentration of Pg was 0.23 mg kg/sup -1/. Radiological assay of grain samples showed no increase in /sup 226/Ra radioactivity in any of three crops due to PG application; PG contained 925 Bq kg/sup -1/ (25 nCi kg/sup -1/) of radioactivity. Analyses of soil after soybean harvest showed that the level of radioactivity level in the subsurface layer was not affected. These results suggest that PG may be applied to agricultural soils at relatively high disposal rates without increasing levels of Cd or radioactivity in corn, wheat, or soybean grain. Applications of By-product PG at recommended rates of 500 to 1000 kg ha/sup -1/ as a source of Ca or S for crops would result in lower levels of Cd and radioactivity than those reported here.
- Research Organization:
- TVA, Muscle Shoals, AL
- OSTI ID:
- 6062881
- Journal Information:
- J. Environ. Qual.; (United States), Vol. 15:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CADMIUM
UPTAKE
GYPSUM
BIOLOGICAL EFFECTS
DOSE-RESPONSE RELATIONSHIPS
PHOSPHORUS COMPOUNDS
RADIUM
GLYCINE HISPIDA
INHIBITION
MAIZE
PLANT GROWTH
PRODUCTIVITY
RESPONSE MODIFYING FACTORS
WHEAT
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
BACTERIA
CALCIUM COMPOUNDS
CALCIUM SULFATES
CEREALS
ELEMENTS
GRASS
GROWTH
LEGUMINOSAE
METALS
MICROORGANISMS
MINERALS
OXYGEN COMPOUNDS
PLANTS
RHIZOBIUM
SULFATE MINERALS
SULFATES
SULFUR COMPOUNDS
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)