D. Badia et Jm. Alcaniz, BASAL AND SPECIFIC MICROBIAL RESPIRATION IN SEMIARID AGRICULTURAL SOILS - ORGANIC AMENDMENT AND IRRIGATION MANAGEMENT EFFECTS, Geomicrobiology journal, 11(3-4), 1993, pp. 261-274
Evolution of microbial activity in semiarid agricultural soils was stu
died measuring the basal (CO2 evolved) and specific microbial respirat
ion (qCO(2)). The effects of straw residue management (buried or remov
ed), irrigation (dry or irrigation farming), and chemical composition
of the soils (calcareous, gypsiferous, or saline) were analyzed. Seaso
nal samplings were carried out over a 2-year period. Both irrigation m
anagement and harvest residue management, as well as soil chemical com
position, influence basal respiration significantly. Straw burying and
water addition increased soil respiration in every sampling. On annua
l average, calcareous soils, with low levels of gypsum and salts and h
igher percentage of organic carbon, evolved the highest rates of carbo
n dioxide. Basal and specific microbial respiration were positively an
d significantly correlated. The release of carbon dioxide per unit of
microbial biomass (qCO,) was considerable in the experimental soils, e
specially with buried straw, although basal respiration was low. High
levels of qCO(2) were related to severe climatic conditions and manage
ment disturbances (ploughing action, fluctuation of organic carbon con
tent), stressing factors that rejuvenate microbial population.