Springer Online Journal Archives 1860-2000
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Abstract Recent findings have highlighted the possibility of increased fluoride (F) concentrations in herbage through F taken up from soil via the plant root. This paper aimed to assess the risk of F concentrations reaching phytotoxic or zootoxic concentrations in pasture plants. Five plant species commonly found in improved pastures in Australia, the sown species subterranean clover (Trifolium subterranean) and cocksfoot (Dactylis glomerata), and weeds barley grass (Hordeum leporinum), scotch thistle (Onopordum acanthium) and sorrel (Rumex acetosella) were grown in complete nutrient solutions with graded levels of added F to determine the effects of F− activity in solution on phytotoxicity and uptake of F by their roots. A model was developed using data from these solution culture experiments and data from the literature. The model assessed uptake of F by plants grown over a range of soil pH values and determined the risk of F taken up through the plant roots reaching phytotoxic concentrations, or concentrations potentially injurious to grazing animals, in the plant shoots. Modelling data suggested that the plants studied would not accumulate phytotoxic concentrations of F in shoots or concentrations of F deleterious to grazing animals through root uptake in neutral pH agricultural soils. The risks from F addition to soils in phosphatic fertilisers leading to reduction in pasture growth or animal health are therefore low. However, in highly F-polluted soil, as the soil becomes more acidic or alkaline, the risk of zootoxic concentrations of F in shoots of plants would increase.
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