Biomass and adenylate energy charge of a grassland soil during drying

• Published in: Soil biology & biochemistry Vol. 22; no. 8; pp. 1121 - 1127
• Main Authors: Rosacker, Laurie L., Kieft, Thomas L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1990; New York, NY Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Fundamental and applied biological sciences. Psychology; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil science; Carbon cycle; Energy metabolism; Nutrition; Soil moisture; Desiccation; Environmental factor; Water potential; Respiration; Microbial biomass; Grassland soil
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/0038-0717(90)90038-2

Grassland soil samples were moistened (50–60% WHC) with water or a nutrient solution (yeast extract: 1 mg C g −1 dry soil) and then dried to matric water potentials of ca −0.80, −2.8, −16.0 or < −70.0 MPa. Samples were collected during drying, and biomass and adenylate energy charge (AEC) were measured. Biomass was measured by the substrate-induced respiration method. Biomass increased in response to initial wetting in all cases, but then decreased as drying progressed. Nutrient amendments resulted in greater peaks of biomass immediately following wetting. The degree of biomass decline during drying was dependent on the rate of drying as well as on the final matric water potential. The AEC values were ca 0.5 before wetting and increased to values as high as 0.75 shortly after wetting. The AEC transiently decreased to values as low as 0.2-0.25, but thereafter returned to ca 0.5. The transient decreases in AEC were caused by high concentrations of AMP which could not be accounted for by hydrolysis of ATP or ADP. This anomalous appearance of AMP may result from endogenous metabolism of RNA.