Summary
Two soils from Pakistan (Hafizabad silt loam and Khurrarianwala silt loam) and one from Illinois, USA (Drummer silty clay loam) were incubated with 15N-labelled soybean tops for up to 20 weeks at 30°C. Mineralization of soybean 15N was slightly more rapid in the Pakistani soils, and after 20 weeks of incubation, 50%, 53%, and 56% of the applied 15N was accounted for as (NH4 ++NO3 −)-N in Drummer, Hafizabad, and Khurrarianwala soils, respectively. Potentially mineralizable N (determined by anaerobic incubation) varied between 1.5% and 10% of the applied 15N in the three soils at different stages of incubation; somewhat higher percentages were mineralizable in the Pakistani soils than in the Drummer soil. From 3.7% to 9% of the applied 15N was accounted for in the microbial biomass. From 10% to 32% of the applied N was recovered in the humic acid and fulvic acid fractions of the organic matter by sequential extraction with Na4P2O7 and NaOH; from 12% to 49% was recovered in the humin fraction. Of the three soils, Drummer soil contained more 15N as humic and fulvic acids. In all cases, the 15N was approximately equally distributed between the humic and fulvic acid fractions. A significant percentage of the humin 15N (52%–78%, equivalent to 8%–34% of the applied 15N) occurred in non-hydrolyzable (6 N HCl) forms. Of the hydrolyzable 15N, 42%–51% was accounted for as amino acid-N followed in order by NH3 (17%–30%), hydrolyzable unknown forms (20%–22%), and amino sugars (6%–2%). The recovery of applied 15N for the different incubation stages was 87±22%. Recovery was lowest with the Khurrarianwala soil, presumably because of NH3 volatilization losses caused by the high pH of this soil.
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References
Anderson JPE, Domsch KH (1975) Measurement of bacterial and fungal contributions to respiration of selected agricultural and forest soils. Can J Microbial 21:314–322
Azam F, Malik KA, Sajjad MI (1985) Transformations in soil and availability to plants of 15N applied as inorganic fertilizer and legume residues. Plant and Soil 86:3–13
Azam F, Malik KA, Sajjad MI (1986) Uptake by wheat plants and turnover within soil fractions of residual N from leguminous plant material and inorganic fertilizer. Plant and Soil 95:97–108
Azam F, Mulvaney RL, Stevenson FJ (1988a) Determination of in situ kN by the chloroform fumigation-incubation method and mineralization of biomass N under anaerobic conditions. Plant and Soil 111:87–93
Azam F, Mulvaney RL, Stevenson FJ (1988b) Chemical distribution and transformations of non-symbiotically fixed 15N in three soils. Soil Biol Biochem (in press)
Brookes PC, Landman A, Pruden G, Jenkinson DS (1985) Chloroform fumigation and the release of soil nitrogen: A rapid direct extraction method to measure microbial biomass nitrogen in soil. Soil Biol Biochem 17:837–842
Cerri CC, Jenkinson DS (1981) Formation of microbial biomass during the decomposition of 14C labelled ryegrass in soil. J Soil Sci 32:619–626
Fokin AD, Karpukhin AI (1974) Incorporation of plant residue decomposition products (labelled with 14C) into humus substances. Soviet Soil Sci 6:687–693
Freney JR, Simpson JR, Denmead OT (1981) Ammonia volatilization. in: Clark FE, Rosswall T (eds) Terrestrial nitrogen cycles. Ecological Bulletins 33, Stockholm, Sweden
He XT, Stevenson FJ, Mulvaney RL, Kelley KR (1988) Incorporation of newly immobilized 15N into stable organic forms in soil. Soil Biol Biochem 20:75–81
Kelley KR, Stevenson FJ (1985) Characterization and extractability of immobilized 15N from the soil microbial biomass. Soil Biol Biochem 17:517–523
Ladd JN, Amato M (1986) The fate of nitrogen from legume and fertilizer sources in soils successively cropped with wheat under field conditions. Soil Biol Biochem 18:417–425
Ladd JN, Oades JM, Amato M (1981) Microbial biomass formed from 14C- and 15N-labelled plant material decomposing in soils in the field. Soil Biol Biochem 13:119–126
Ladd JN, Jackson RB, Amato M, Butler JHA (1983) Utilization by wheat crops of nitrogen from 15N-labelled legume residues decomposing in soils in the field. Soil Biol Biochem 15:231–238
Ladd JN, Amato M, Oades JM (1985) Decomposition of plant material in Australian soils: III. Organic and microbial biomass C and N from isotope-labelled legume material and soil organic matter, decomposing under field conditions. Aust J Soil Res 23:603–611
Martin JP, Filip Z, Haider K (1976) Effect of montmorillonite and humate on growth and metabolic activity of some actinomycetes. Soil Biol Biochem 8:409–413
Mulvaney RL, Kurtz LT (1982) A new method for determination of 15N labelled nitrous oxide. Soil Sci Soc Am J 46:1178–1184
Sörenseon LH (1981) Carbon-nitrogen relationship during the humification of cellulose in soils containing different amounts of clay. Soil Biol Biochem 13:313–321
Sörenson LH (1983) The influence of stress treatments on the microbial biomass and the rate of decomposition of humified matter in soils containing different amounts of clay. Plant and Soil 75:107–119
Stevenson FJ (1982a) Nitrogen — organic forms. In: Page AL, Miller RH, Keeney DR (eds) Methods of soil analysis. Am Soc Agron, Monogr 10, vol 2, 2nd edn, Madison, Wise, pp 625–641
Stevenson FJ (1982b) Organic forms of nitrogen. In: Stevenson FJ (ed) Nitrogen in agricultural soils. Am Soc Agron, Monogr 22, Madison, Wise, pp 67–122
Waring SA, Bremner JM (1964) Ammonium production in soil under waterlogged conditions as an index of nitrogen availability. Nature (Lond) 201:951–952
van Veen JA, Ladd JN, Amato M (1985) Turnover of carbon and nitrogen through the microbial biomass in a sandy clay and a clay soil incubated with [14C(U)] glucose and [15N] (NH4)2SO4 under different moisture regimes. Soil Biol Biochem 17:747–756
Wojcik-Wojtkowiak D (1972) The transformation of nitrogen and carbon in the soil during humification of straw labelled with 15N. Plant and Soil 36:261–270
Wojcik-Wojtkowiak D (1978) Nitrogen transformation in soil during humification of straw labelled with 15N. Plant and Soil 49:49–55
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Azam, F., Mulvaney, R.L. & Stevenson, F.J. Transformation of 15N-labelled leguminous plant material in three contrasting soils. Biol Fert Soils 8, 54–60 (1989). https://doi.org/10.1007/BF00260516
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DOI: https://doi.org/10.1007/BF00260516