Showing 2 results for Chemical Extractants.
H. R. Motaghian, A. R. Hosseinpur, F. Raiesi, J. Mohammadi,
Volume 18, Issue 67 (6-2014)
Abstract
Rhizosphere is a small zone and has quite different chemical, physical, and biological properties from bulk soil. This research was performed to study the available Zn and its fractions in the wheat rhizosphere and bulk soils by using rhizobox at greenhouse conditions. Total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and available Zn using 7 chemical procedures and Zn-fractions were determined in the rhizosphere and bulk soils. The results indicated that TOC, DOC and MBC in the rhizosphere were increased significantly (P<0.01). Zn extracted using several chemical extractants (except 0.01 M CaCl2) in the rhizosphere were significantly (p<0.05) higher than in the bulk soils. Also, concentrations of Zn-fractions (except carbonate-associated) in the rhizosphere were significantly (p<0.05) different from concentrations of Zn-fractions in the bulk soils. Results indicated that correlation between uptake index and extracted Zn using DTPA-TEA and Mehlich 3 were significant (p<0.05). Moreover, significant correlation (p<0.05) between uptake index and exchangeable Zn and Zn associated with iron-manganese in the wheat rhizosphere and bulk soils were found. The results of this research illustrated that available Zn and its fractions in the rhizosphere soils are different from the bulk soils. Therefore, application of the rhizosphere soil would be recommended in the study on these properties after planting.
T. Raiesi, A. Hosseinpur,
Volume 19, Issue 71 (6-2015)
Abstract
The ability of different soil tests in predicting soil phosphorus (P) is important in soils amended with municipal sewage sludge. The objective of the present study was to evaluate several chemical extractants to estimate available P for bean growing in 10 calcareous soils amended with municipal sewage sludge from Chaharmahal-Va-Bakhtiari province under the greenhouse conditions. For this purpose, the soil samples were incubated with sludge at a rate of 39-ton sludge ha–1. The amount of available P of the soil samples was determined by Olsen, Colwell, ammonium bicarbonate-DTPA, 0.01 M calcium chloride, BrayІ, ІІ, Mehlich І and ІІ methods. A pot experiment in a completely randomized design was conducted to evaluate the bean plant indices. The results showed that the amount of extractable P with the above methods decreased in the following order: Colwell> Bray ІІ> Mehlich ІІ> Olsen> Ammonium bicarbonate DTPA> Mehlich І> Bray І> 0.01M chloride calcium. The extractable P with 0.01M chloride calcium, Mehlich І, ІІ Colwell and Olsen methods correlated significantly with plant indices (P concentration and P uptake). Thus, mentioned methods could be used to estimate plant-available P in the soils amended with sewage sludge.
