Fluoride In Soil Research Articles

Determination of total fluoride in soil and vegetation using an alkali fusion-selective ion electrode technique

Determination of total fluoride in soil and vegetation using an alkali fusion-selective ion electrode technique

Distribution of Soil Fluorides Near an Airborne Fluoride Source

AbstractThe purpose of the study was to determine the effect of a major source of airborne fluorides on the geographical distribution of total fluoride in soils. Total fluoride determinations were made on soil samples collected from the same pastures at different distances from the source in spring and fall of 1973 and 1974. Samples were collected at depths of 0–5, 5–15, and 15–30 cm. Forage fluoride levels were used to determine areas of relatively high and low airborne fluoride impact, and soil sampling locations within these respective areas were segregated accordingly. Total soil fluoride increased with depth at low fluoride impact sites, but decreased with depth at high impact sites. This was a result of significantly (p = 0.05) elevated fluoride levels at the 0–5 cm depth on high impact sites compared to low impact areas. Total soil fluoride for all depths decreased with distance from the fluoride source, and approximated background levels at about 10 km. It is concluded that the observed magnitude of atmospheric fluoride contribution to total soil fluoride will probably have no significant impact on agriculture.

Studies on Environmental Pollution by Fluoride. II. Determination of Fluoride in Soil

Studies on Environmental Pollution by Fluoride. II. Determination of Fluoride in Soil

Fluoride Induced Necrosis of Cordyline terminalis Kunth ‘Baby Dolt’ as Influenced by Medium and pH1,2

Abstract Although grown by foliage growers for its colorful red leaves, Cordyline terminalis Kunth ‘Baby Doll’ often develops foliar necrosis during propagation. Propagating media had a pronounced influence on amount of necrosis, but soluble salts, pH, and cation exchange capacities of the media offered few clues for the variation. Necrosis was related to soluble soil fluoride. Addition of superphosphate containing 1.6% fluorine (F) increased leaf tissue F and tip necrosis, and both were reduced when media pH increased with liming amendments.

Determination of Fluoride in Soils by a Nonfusion Distillation pF Method

The nonfusion distillation pF method has been successfully applied to the determination of fluoride in soils. The fluoride is distilled from the soil sample with HClO4 and measured in the buffered distillate by an ion-specific fluoride electrode without any ashing or other separation operations. Soils or mud containing fluoride in the range between 1 to 700 ppm can be directly analyzed with a standard error of less than 1.5%.

SOIL FLUORINE

SummaryThe development of techniques for measuring soluble and labile soil fluoride using a specific‐ion fluoride electrode are described. The methods evolved were used to assess the fluoride status of numerous agricultural soil samples in addition soils which had received known fluoride additions. Two soil profiles were analysed with respect to distribution with depth of soluble and labile fluoride.The equilibrium‐fluoride concentration was determined after shaking the soil with a 0.01 M CaCl, solution. Isotopically exchangeable (labile) soil fluoride was determined by use of the radioactive fluorine isotope 18F. These labile fluoride values were well correlated with the amount of soil fluoride extracted by an anionexchange resin, and the latter method was consequently adopted for further determinations of labile soil fluoride.Nearly half the 1OO agricultural soil samples examined gave fluoride concentrations < 0.2 ppm in 0.01 M CaCl, extracts whereas labile fluoride values were evenly distributed around a mean of 20 ppm. For any given pH value, there appeared be an upper limit to the solubility of soil fluoride. Application to soil of superphosphate (in the field) or of fertilizer containing fluoride (in the laboratory) brought about increases in soluble soil fluoride.

FIXATION, LEACHING, AND PLANT UPTAKE OF FLUORINE FROM ADDITIONS OF CERTAIN FLUORIDS IN REPRESENTATIVE SANDY SOILS

Experiments were conducted to determine the effects of fluorides upon the fertility of sandy soils. The results of soil leaching of fluorides, as well as the possible effect of additive fluorides upon seed emergence and plant response are presented. Related uptake of fluorine by plants at various durations of growth were investigated. Observations reveal that grass seed was not affected by an additive fluoride in the sandy soil. Under greenhouse conditions the grass took up additive fluorine from the acidic Florida sand at pH 4.1 to 4.5, and the grass took up F from New Jersey soil at pH 5.3. Dolomite incorporation of 1000 pounds per acre exerted no significant effect upon F uptake from the Florida soil. Fluorine uptake by the grass on the New Jersey soil, which has a greater F content, exceeded uptake from the Florida soil. Fluorine uptake diminished progressively in the successive crops grown on Florida soil and the F content became less with the age of grass on this soil, even where fluorides had been added. The first and second crops from the New Jersey soil showed virtually no difference in their F content; but both crops registered F uptakes beyond those from themore » corresponding Florida crops. This reflects the decidedly larger soil content of F, due either to mineral content or to natural increments.« less