Title: Canola residues decomposition: the effect of particle size on microbial respiration and cycling of sulphur in a sandy soil
Abstract: A study on canola residue decomposition was conducted under controlled conditions for 183 days to elucidate the effect of its particle size (<1 mm, 5–7 mm, 20–25 mm) on microbial respiration, microbial-S and plant-available S (SO4 2– ) after incorporation into a nutrient-deficient sandy soil. Variation in the particle size of canola residue did not affect net cumulative CO2-C respiration (as % of added C), the size of microbial-S pool, and the extent of sulphate-S immobilisation, except for the slower decomposition of the <1 mm residue in the soil between days 7–28 of incubation. In total, 33–35% of the residue-C added was respired during 183 days of incubation. About 75% of S added in canola residue to the soil was extracted as sulphate-S upon extraction with 0.01 M CaCl2 immediately after incorporation (day zero), indicating that canola residue is a good source of readily-available S. The initial sulphate-S in the amended soil on day zero was reduced to 65% on day 183 after incorporation. On average, more microbial-S was present in the amended (3.2 mg/kg soil) than in the non-amended soil (2 mg/kg soil) throughout. In conclusion, the cumulative respiration at the end of 6-month incubation was similar regardless of the particle size of canola residues. Furthermore, adding canola residue to the soil significantly increased (4-fold) the initial soil sulphate-S level, which decreased by one-third over time. This finding indicates microbial immobilisation and transformation of inorganic-S to stable organic-S in the amended soil.
Publication Year: 2004
Publication Date: 2004-01-01
Language: en
Type: article
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Cited By Count: 5
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