Rw. Odowd et Dw. Hopkins, MINERALIZATION OF CARBON FROM D-AMINO-ACID AND L-AMINO-ACID AND D-GLUCOSE IN 2 CONTRASTING SOILS, Soil biology & biochemistry, 30(14), 1998, pp. 2009-2016
Following addition of either the D- or the L-isomers of alanine, gluta
mine or glutamic acid or D-glucose, the CO2 production from an arable
and a forest soil was measured until the pulses of CO2 production asso
ciated with substrate addition subsided. The maximum rate of additiona
l CO2 production from the D-glucose amended soils occurred within the
first 48 h for both soils. The greatest rates of additional CO2 produc
tion from L-amino acid amended soils occurred within 108 h for the for
est soil and 60 h for the arable soil. Following addition of D-amino a
cids to the forest soil, the maximum rate of additional CO2 production
was less than that following addition of the corresponding L-amino ac
id addition. However, for this soil the pulse of additional CO2 produc
tion following D-amino acid amendment lasted longer and by the time it
had subsided (360 h), the total additional CO2 production did not dif
fer between isomeric forms of the same amino acid. Following D-amino a
cid addition to the arable soil, there were delays of between about 24
and 48 h before the onset of rapid additional CO2 production and the
CO2 pulse subsided relatively rapidly. The total additional CO2 produc
ed from the arable soil was significantly less for the D-amino acid;th
an for the Corresponding L-amino acid treatments. Successive additions
of D-glucose led to significant increases in the subsequent rates of
additional CO2 production from the forest soil, but not from the arabl
e soil. Each successive L-amino acid amendment led to increases in the
rare of additional CO2 production from both soils, as did successive
additions of the D-amino acids to the forest soil. However, successive
additions of the D-amino acids to the arable soil did not lead to con
sistent responses in the additional rate of CO2 production. (C) 1998 E
lsevier Science Ltd. All rights reserved.