Decomposition and humification in soil of plant residues differing in chemical composition
2002
Sajjad, M.H. (Nuclear Inst. for Agriculture and Biology, Faisalabad (Pakistan). Rhizobiology Lab.) | Bhatti, H.N. | Lodhi, A. | Azam, F.
Soil samples amended with powdered plant material of wheat, maize, and sesbania were incubated for 8 weeks at ure content of 60% of the maximum water holding capacity and 22-26 degree centigrade for 8 weeks. At 0, 2, 4 and 8 weeks of incubation, ions of soil were analyzed for l) total C and its distribution in mic and fulvic acid fractions and ii) optical properties of humic Humus fractions were extracted with both sodium hydroxide NaOH) and sodium pyrophosphate (Na4P207). Higher amounts of humus C were extracted with NaOH than with Na4P207; the treatment differences were more obvious in former. Organic amendment resulted in higher amounts of humic and fulvic acid; more humus C being found in soil amended with maize and wheat. More N was determined in humic acid compared with fulvic acid following the extraction of soil with NaOH. Nature of organic amendment and the extractant used had a significant effect on C/N ratio of humic compounds. Optical density of the humic acid fraction decreased at the increasing wavelength and was correlated significantly with the C content of humic acid. Duration of incubation and nature of amendment had a significant effect on the polymerization and maturity of the humic acid fraction.
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