Effects of temperature on extractable manganese and distribution of manganese among soil fractions

Abstract

Fertiliser manganese (Mn) does not have good residual value in calcareous soils in southern Australia. The interaction of biotic and abiotic factors determining availability of fertiliser Mn is not well understood. Effects of autoclaving and temperature of moist incubation on DTPA (diethylenetriaminepentaacetic acid)-extractable Mn and the distribution of Mn among soil fractions was tested in a sandy, calcareous Wangary soil. In the topsoil receiving 10 or 40 mg Mn/kg, higher incubation temperature (26°C) accelerated a decrease in DTPA-Mn and weakly adsorbed Mn during 0-14 d incubation compared with the lower temperature (15/10°C, 12 h each) regardless of whether soil was autoclaved or not. In a Wangary soil mixed in 1:1 ratio of topsoil to subsoil and supplemented with Mn, higher temperature during soil incubation resulted in higher DTPA-Mn compared to the lower incubation temperature after 36 d. The decrease in weakly adsorbed Mn with incubation time was mainly due to: (i) Mn fixation by chemisorption on calcite, and (ii) Mn oxidation by soil microflora; the higher the incubation temperature, the quicker the fixation. Autoclaving of the soil fertilised with Mn caused the amounts of Mn in various soil fractions to remain almost constant throughout the 24-d incubation period regardless of the incubation 1. Present address:

Influence of Temperature on the Toxicity of Zinc to the Earthworm Eisenia fetida

“…DTPA-extractable metal concentrations generally supported the results of the plant analysis. In contrast to the above results suggesting an increase in metal availability at high temperature, Tong et al, (1995) found that the incubation of manganese spiked soils at high temperatures accelerated a decline in the DTPA-extractable metal levels, indicating lower solubility. Thus although some evidence exists indicating greater solubility of metals at high temperatures, data are not consistent between studies with different metals.…”

Micronutrient fractionation and plant availability in bauxite-processing residue sand

“…A relatively high proportion of Mn was associated with carbonate-bound forms, which might be due to higher CaCO 3 content of residue sand sources, or through precipitation as MnCO 3 . Strong association of Mn with the carbonate fraction was reported for soils by Tong et al (1995) and for bauxite residue by Gherardi and Rengel (2001). There was a strong relationship between carbonate bound…”

“…On average, 40-66% of total Mn was associated with the residual fraction and 12-45% in Fe-Mn oxide bound fractions. Strong retention of Mn by the oxide fraction has previously been found for both soil and bauxite residue sand, and has also been related to the low affinity of Mn for organic compounds (Goldberg and Smith 1984;Tong et al 1995;Gherardi and Rengel 2001). Samples from India exhibited higher Mn concentrations in the residual and Fe-Mn oxide bound fractions than the Australian sample.…”

Interactions Between Nitrogen and Manganese Nutrition of Barley Genotypes Differing in Manganese Efficiency

“…The pH-buffering capacity of soil used in expt B is relatively lower and larger root-induced pH changes related to N sources may occur in this soil. DTPAextractable Mn increased from 3n2 to 3n7 mg kg − " in soil used in expt B after application of 50 mg Mn kg − " ; DTPA-Mn increased from 0n1 to 1n0 mg kg − " in soil used in expt A 36 d after application of 40 mg Mn kg − " (Tong et al, 1995), indicating that both soils had considerable capacity for fixing Mn into non-extractable forms. The mechanism of Mn fixation, however, is probably different given the vast differences between the two soils in pH and CaCO $ content (Tong, Rengel and Graham, unpubl.…”

“…DTPA-extractable Mn (moist soil) before Mn fertilization was 0n1 mg kg − ". Further details on chemistry of soil Mn in various fractions are given elsewhere (Tong, Rengel and Graham, 1995). Manganese treatments were applied as solutions of MnSO % in double-deionized water (18 MΩ cm resistivity).…”