TY - JOUR
T1 - Effect of reducing conditions on P sorption of soils
AU - Nanzyo, Masami
AU - Kanno, Hidenobu
AU - Obara, Sawae
PY - 2004/2/1
Y1 - 2004/2/1
N2 - The phosphate sorption (Psor) capacity of soils increased when the soils were reduced (Willet and Higgins, Aust. J. Soil Res., 16, 319–326, 1978). The present study aimed at the elucidation of this mechanism using Na2S2O4 and 5 different soils. The Psor of the 5 soils increased with the addition of a small amount of Na2S2O4. Fe(II) was released from the soils with the addition of the same small amount of Na2S2O4. Furthermore, when the amount of FeCl2 corresponding to the amount of Fe(II) released along with the small amount of Na2S2O4 was added, the Psor of the soil increased. However, the Psor of the lowland soils, of which the hydrous Fe oxide content was lower than the others, decreased when the amount of Na2S2O4 addition was increased up to 150–200 g kg−1. Based on these results, the following process is inferred for the increase in the Psor of the soils when they are reduced. Hydrous Fe oxide in soil takes the form of very fine, high-density particles and reacts with P mainly on their surface. When a small amount of Na2S2O4 is added, the hydrous Fe oxide is partially reduced, dissolved and finally re-precipitates with P by oxidation with O2 from the air during the experiment.
AB - The phosphate sorption (Psor) capacity of soils increased when the soils were reduced (Willet and Higgins, Aust. J. Soil Res., 16, 319–326, 1978). The present study aimed at the elucidation of this mechanism using Na2S2O4 and 5 different soils. The Psor of the 5 soils increased with the addition of a small amount of Na2S2O4. Fe(II) was released from the soils with the addition of the same small amount of Na2S2O4. Furthermore, when the amount of FeCl2 corresponding to the amount of Fe(II) released along with the small amount of Na2S2O4 was added, the Psor of the soil increased. However, the Psor of the lowland soils, of which the hydrous Fe oxide content was lower than the others, decreased when the amount of Na2S2O4 addition was increased up to 150–200 g kg−1. Based on these results, the following process is inferred for the increase in the Psor of the soils when they are reduced. Hydrous Fe oxide in soil takes the form of very fine, high-density particles and reacts with P mainly on their surface. When a small amount of Na2S2O4 is added, the hydrous Fe oxide is partially reduced, dissolved and finally re-precipitates with P by oxidation with O2 from the air during the experiment.
KW - Dithionite
KW - Iron
KW - Phosphate
KW - Redox
KW - Sorption
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U2 - 10.1080/00380768.2004.10408569
DO - 10.1080/00380768.2004.10408569
M3 - Article
AN - SCOPUS:11144350220
VL - 50
SP - 1023
EP - 1028
JO - Soil Science and Plant Nutrition
JF - Soil Science and Plant Nutrition
SN - 0038-0768
IS - 7
ER -