Basal respiration and composition of microbial biomass in virgin and agroforest-reclaimed semidesert soils of the Northern Caspian region
Abstract
Virgin semidesert soils and their analogues subjected to agroforest reclamation 60 years ago were studied in the area of the Dzhanybek Research Station of the Institute of Forest Science of the Russian Academy of Sciences in the Northern Caspian region. The values of Cmic and soil basal respiration (BR) significantly vary among the separate plots. In the 0- to 10-cm layer, the BR rate is 0.28-2.44 μg C-CO2/(g h); the minimum values are typical for the arable soils of the interbelt area, and the maximum values are found in the meadow-chestnut soils of mesodepressions under the forest belt with a strong zoogenic effect. The content of Cmic increases from 415 to 1388 μg C/g soil in the following series: virgin solonetz-agro-afforested soils- virgin meadow-chestnut soils = their forest analogues. The fungi/bacteria ratio is 1.3-3.0; the fungal component of soils reaches 53-85% of Cmic, and its absolute values increase from 236 to 1040 μg C/g in the same soil series. Correlation was found between Corg and BR ( r = 0.89), between Corg and Cmic ( r = 0.87), and between BR and Cmic ( r = 0.89). The portion of Cmic in Corg is 3.2-8.6%; the minimum values are found for virgin solonetz and meadow-chestnut soil under forest belt with strong zoogenic effect. The values of qCO2 (ratio of BR to Cmic) are in the range of 0.7-2 μg C-CO2/(mg Cmic g h). At the afforestation of soils in natural and artificial mesodepressions, the activation of microbial community and humification processes is noted compared to the virgin analogues; unstable microbiological processes and a decreased Corg content because of deep tillage and the reduced input of plant residues in the permanent bare fallow between forest belts are revealed in the agro-afforested solonetzes and meadow-chestnut soils of microdepressions.
- Publication:
-
Eurasian Soil Science
- Pub Date:
- August 2015
- DOI:
- 10.1134/S1064229315080049
- Bibcode:
- 2015EurSS..48..852P
- Keywords:
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- fungi/bacteria ratio;
- clay semidesert;
- solonetzes;
- meadow-chestnut soils of micro- and mesodepressions;
- forest plantations