Selenium Concentrations in Phosphorus Fertilizer Materials and Associated Uptake by Plants

Abstract

The Se concentration of seven Florida Land Pebble deposit phosphate rocks ranged from 0.7–7.0 ppm. The range was 1.4–178 ppm Se in seven samples from the western phosphate field. The Meade Peak phosphatic shale member of the Phosphoria formation contains more Se than rock from other phosphatic formations. Normal and concentrated superphosphates made from phosphatic rocks containing 100 ppm Se can be expected to contain about 60 and 40 ppm Se, respectively. Laboratory‐prepared concentrated superphosphate containing 23 ppm Se applied to an alkaline soil that normally produced alfalfa (Medicago sativa L.) low in Se at a rate of 156 ppm P increased Se concentration in alfalfa above the minimal requirements to protect livestock from white muscle disease. Concentrated superphosphate and single superphosphate prepared from phosphate rock containing 178 ppm Se and applied at a rate of 80 ppm P increased the Se concentration in alfalfa compared to the same amount of P applied as Se free concentrated superphosphate. Normal phosphate fertilizer practices can provide required Se for livestock provided the fertilizer is prepared from phosphate rock containing sufficient Se.

Selenium behavior in the soil environment and its implication for human health

“…In spite of the wide range of variation of individual values, higher Se concentrations can be found in the sedimentary rocks such as limestones (<0.1-7.4 mg kg -1 ), sandstones (<0.1-1.7 mg kg -1 ), and shales (<0.1-12.0 mg kg -1 ) (Connor and Schaklette, 1975). Very high Se contents have been reported in some phosphate-rich rocks (Robbins and Carter, 1970), marine or black shales (Ryan and Dittrick, 2000), coals (Coleman et al, 1993), and other rocks enriched with organic carbon. Some components of sulphide mineral deposits can also be source of Se to the environment, whereas elemental Se 0 is rarely mentioned in literature (Fordyce, 2007).…”

Effect of Phosphorus Fertilization on the Selenium Concentration in Alfalfa (Medicago sativa)

“…The available information on the Se concentration in soils (14), the different Se forms and their reactions in soils, and the Se uptake by plants (4,6,8,12,17) tration in forage resulted from different management practices. Crop rotations and fertilizer practices used in the variable areas indicated that some of the variability may be related to P fertilization.…”

“…Crop rotations and fertilizer practices used in the variable areas indicated that some of the variability may be related to P fertilization. We investigated the Se concentration in P fertilizer materials and the associated uptake by plants (17), and results established that some P fertilizers contain sufficient Se to enhance concentrations in plants. However, the proportion of the P fertilizers containing significant amounts of Se appeared too small to explain much of the observed variability in the field.…”

“…Study I-This study was carried out simultaneously with our investigation of the plant uptake of Se contained in P fertilizer materials (17). Treatments were: (i) control, (ii) raw rock phosphate at a rate sufficient to provide 22 ppm P and 0.008 ppm Se, (iii) raw rock phosphate treated with enough H3PO4 to provide 79 ppm P and 0.008 ppm Se, (iv) raw rock phosphate treated with H2504 applied at a rate sufficient to provide 44 ppm P and 0.016 ppm Se, and (v) raw rock phosphate treated with H3PO4 equivalent to the H2SO4 used in (iv) to provide 156 ppm P and 0.016 ppm Se.…”

Some Aspects of Selenium Relationships in Eastern Canadian Soils and Plants

“…The water-soluble Se was found to be of doubtful value as an index of Se availability for Se-deficient soils; but it was a useful criterion for assessing the behavior of Se applied to soil. Se (Robbins and Carter 1970) (Bisbjerg and Gissel-Nielsen 1969;Robbins and Carter 1970 (Wells 1967). The higher Se levels coincided with high C contents.…”