Sulfur transformation in 3 soils maintained in a closed incubation system and its availability to plants were investigated using carrier-free35S-SO42- and 35S-labeled ryegrass straw. For carrier-free Na235SO4 treatmen...Sulfur transformation in 3 soils maintained in a closed incubation system and its availability to plants were investigated using carrier-free35S-SO42- and 35S-labeled ryegrass straw. For carrier-free Na235SO4 treatment, 78%, 70% and 64% of 35S applied were found in Ca (H2PO4)2-extractble S fraction 14%, 5% and 7% in slowly soluble inorganic S, 11%, 15% and 18% in C-O-S, 5%, 7% and 6% in C-bonded S, and 5%,7% and 6% in unidentified organic S 120 days after incubation in black soil, cinnamon soil and chestnut soil, respectively. Most of 35S uptake by plants came from extractable 35S42-, and little from C-O-35S and C-bonded 355. In the treatment with 35S-labeled straw, 51%, 46% and 36% of 355 incorporated were found in C a (H2PO4)2 -extractable S fraction) 7%, 6% and 7% in slowly solub ie inorganic S, 13%, 15% and 18% in C-O-S, 8%, 8% and 6% in C-bonded S, and 18%, 25% and 35% in unidentified organic S at the end of incubation in above-mentioned three soils, respectively. Higher availability of C-O-35S, C-bonded 35S and unidentified organic 35S from 35S-labeled straw was observed in 35S-labeled straw treatment compared to carrier-free Na235SO4 treatment.展开更多
文摘Sulfur transformation in 3 soils maintained in a closed incubation system and its availability to plants were investigated using carrier-free35S-SO42- and 35S-labeled ryegrass straw. For carrier-free Na235SO4 treatment, 78%, 70% and 64% of 35S applied were found in Ca (H2PO4)2-extractble S fraction 14%, 5% and 7% in slowly soluble inorganic S, 11%, 15% and 18% in C-O-S, 5%, 7% and 6% in C-bonded S, and 5%,7% and 6% in unidentified organic S 120 days after incubation in black soil, cinnamon soil and chestnut soil, respectively. Most of 35S uptake by plants came from extractable 35S42-, and little from C-O-35S and C-bonded 355. In the treatment with 35S-labeled straw, 51%, 46% and 36% of 355 incorporated were found in C a (H2PO4)2 -extractable S fraction) 7%, 6% and 7% in slowly solub ie inorganic S, 13%, 15% and 18% in C-O-S, 8%, 8% and 6% in C-bonded S, and 18%, 25% and 35% in unidentified organic S at the end of incubation in above-mentioned three soils, respectively. Higher availability of C-O-35S, C-bonded 35S and unidentified organic 35S from 35S-labeled straw was observed in 35S-labeled straw treatment compared to carrier-free Na235SO4 treatment.
