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STUDIES ON THE DECOMPOSITION OF PLANT MATERIAL IN SOIL. I.t
Author(s) -
JENKINSON D. S.
Publication year - 1965
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1965.tb01424.x
Subject(s) - decomposition , tops , soil water , agronomy , chemistry , zoology , biology , ecology , spinning , organic chemistry , polymer chemistry
Summary A new method for determining I4 C in soil is described. Ryegrass roots and tops uniformly labelled with 14 C were allowed to decompose for 4 years in soil under field conditions. About one‐third of the labelled (ryegrass) C was left in the soil after 6 months but thereafter decomposition was much slower, about one fifth of the labelled C remaining after 4 years. Throughout the period, labelled C was less resistant to decomposition than unlabelled C, i.e. the C present in the soil before the labelled ryegrass was added. Even in the fourth year after addition of the ryegrass, the percentage of labelled C in the soil decomposing per year was four times that of unlabelled C. Initially, ryegrass tops decomposed more quickly than roots but after I year the differences disappeared and the same amount of residual C remained from each. For periods of I year and over, the percentage of labelled C retained in a soil with 2.4 per cent organic C was the same as in a soil containing 1 per cent organic C. The percentage C retained was the same when either 0.3 per cent ryegrass tops or 0.6 per cent ryegrass tops were added to the soil. Similar amounts of labelled plant C were retained in soils incubated for 1 year in two contrasting seasons (1959 and 1962).