Aggregate Associated Sulfur Fractions in Long-Term (>80 Years) Fertilized Soils
- Zhihui Yang,
- Bal Ram Singh *,
- Sissel Hansen,
- Zhengyi Hu and
- Hugh Riley
- D ep. of Plant and Environmental Sciences, Norwegian Univ. of Life Sciences, P.O. Box 5003, N-1432 Aas, Norway
B ioforsk-Norwegian Agric. & Environ.Res. Inst., Organic Food and Farming Division, N-6630 Tingvoll, Norway
I nstitute of Soil Science, Chinese Academy of Sciences, No. 71, E. Beijing Rd., P.O. Box 821, Nanjing, 210008, P.R.China
B ioforsk-Norwegian Agric. & Environ. Res. Inst., Arable Crops Division, N-2350 Kisevegen 337, Nes På Hedmark, Norway
Understanding soil sulfur pools and associated aggregates S fractions can provide a platform for monitoring S dynamics in soils. A long-term experiment established in 1922 on an Aquic Eutrocryepts in South-eastern Norway was chosen to investigate the effects of long-term fertilization on S fractions in bulk soil and those associated with aggregates. Chloroform fumigation-extraction was used to determine Microbial biomass S (MBS) and the wet chemical analysis method was used to fractionate soil S into ester S (hydriodic acid reducible S), carbon-bonded S (Raney nickel reducible S) and residual S (Raney nickel non-reducible S). High farmyard manure (FYM) application resulted in higher MBS in bulk soil than nitrogen + potassium (NK) application, but it did not differ significantly from the control. Application of FYM at 60 Mg ha−1 resulted into accumulation of total S, total organic S and carbon-bonded S in bulk soils, while mineral fertilizer (nitrogen+phosphorus+potassium+sulfur [NPKS] and NK) and the medium rate of FYM did not increase the accumulation of total S and organic S fractions. The macroaggregate sizes (>2 and 1–2 mm) and the finest aggregate size (<0.106 mm) showed significantly greater total S concentration than other aggregate sizes. Ester S and residual S were predominant organic S fractions and they accounted for 39 to 52% and 38 to 51% of the organic S, respectively. The macroaggregate sizes (>2 and 1–2 mm) contained the highest ester S, but microaggregates (<0.106 mm) exhibited higher carbon-bonded S and residual S than other aggregates. In conclusion, the accumulation of S was dependent on fertilizer type, the rate of FYM application and aggregate sizes.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2007.