Journal article
Organic Matter and Microbial Biomass in a Soil Incubated in the Field for 20 Years with 14C-Labelled Barley Straw
14C-labelled barley straw was incubated under field conditions in a sandy soil. After 8 yr, 16% of the labelled C added remained in the soil; after 20 yr 9.3%. During the 8 to 20 yr period the labelled organic matter in the soil decayed at a rate corresponding to a half life of 15 yr. The percentage of residual labelled C in amino acids remained almost constant during the period, being on average 21%.
The soil contained 1.9% native C in organic matter; during the 8 to 20 yr period this decayed at a rate corresponding to a half life of 91 yr. The percentage of native C in amino acids increased significantly, from about 14% to about 16%.During the 8 to 20 yr period, microbial biomass was determined yearly by the chloroform fumigation technique.
The proportion of total labelled C in biomass remained nearly constant during this period, on average 2.7%. Labelled C in biomass decreased at a rate corresponding to a half life of 8 yr. The native biomass increased during the same period from 0.7 to 1.4% of the total native soil C.As measured by CO2 produced during periods of 3 months, laboratory incubation increased the rate of decay of the labelled organic matter by a factor of 1.2 and that of the native organic matter by a factor of 4.3.
Language: | English |
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Year: | 1987 |
Pages: | 39-42 |
ISSN: | 18793428 and 00380717 |
Types: | Journal article |
DOI: | 10.1016/0038-0717(87)90123-4 |