Plant availability of inorganic and organic selenium fertiliser as influenced by soil organic matter content and pH

Abstract

The objective of the present study was to investigate the influence of soil organic matter content and pH on plant availability of both inorganic and organic selenium (Se) fertilisers. Further, the risk of Se leaching after application of inorganic Se fertiliser was evaluated. A new interpretation of an older field study at different sites in Southern Norway showed that organic C was correlated with grain Se concentration in wheat, barley and oats, explaining up to 60% of the variation in Se concentration. Pot experiments with a peat soil, a loam soil and a peat/ loam soil mixture were conducted for the present study at a range of pH values between pH 5 and 7. Below pH 6, Se uptake from added Se fertiliser was higher in the soil types with high organic matter content than in the loam. The opposite occurred at a soil pH above 6, where Se uptake was higher in the loam than in the peat soil. A simple leaching experiment after one growing season confirmed the findings of the pot experiments that Se availability in the loam soil with a relatively low organic matter content increased with increasing pH, whereas it decreased in the peat soil. Neither Se yeast, nor pure Se methionine, used as organic Se fertiliser, resulted in any significant uptake of Se when added at concentrations similar to the inorganic Se applications.

Status of Selenium and Trace Elements in some Arid Soils Cultivated with Forage Plants: A Case Study from Saudi Arabia

“…These conditions might provide chemical constraints for agricultural production associated with the alkaline soil environment and the dry land climate, which include macronutrient and micronutrient deficiencies and some toxicity related to high sodicity and salinity. Though a higher Se availability to plants can generally be expected in mineral soils having high pH (Eich-Greatorex et al, 2007), the current study showed that shoot Se concentrations was very low and deficient. This can be explained by the low soil content of total Se rather than chemical constraints of the study soils having high sand content.…”

“…Trace elements are also involved in key metabolic events such as respiration, photosynthesis, and fixation and assimilation of some major nutrients (Kabata-Pendias and Pendias, 1991). Among trace elements, the low selenium (Se) content and availability in the soils are of concern (Eich-Greatorex et al, 2007). Se is an essential microelement, necessary for normal functioning of humans and animals (Rayman, 2000).…”

“…Low Se content and availability of the soil can show selenium deficiency-related diseases such as white muscle in animals and pancreatic degeneration in poultry (Thompson and Scoot, 1970). Se is one of the most important trace elements for both human and animal health and plays an important role in preventing the disease through its function in the antioxidant enzyme of glutathione peroxidases (Rayman, 2000;Eich-Greatorex et al, 2007). However, high concentrations of Se are toxic for humans, animals and plants.…”

Selenium – An Important Antioxidant in Crops Biofortification

“…Availability of selenium applied in such manner is usually 5 to 30 %. Residual part is retained in soil, leached, eventually released to atmosphere through volatilization [30].…”

“…In soils rich in organic matter and water and without air entry selenates are transformed and reduced to less mobile forms [32]. With decreasing pH and redox potential in soil SeO3 2-dominate, being less available for plants than SeO4 2- [30]. This fact results from different physical characteristics of soils containing SeO3 2-or SeO4 2-and from different mechanism of absorption of both anions.…”