THE INFLUENCE OF LONG-TERM FERTILIZER APPLICATION ON THE RESPIRATION ACTIVITY AND RESILIENCE OF SOIL MICROBIAL COMMUNITIES

For estimating soil resilience, a coefficient of microbial respiration defined as a ratio between rates of basal and substrate-induced respi ration was determined, Q(R) = V-basal/V-SIR The respiration activity o f soils depended on the season, experimental variant, and soil type. L ong-term agricultural use of soils resulted in the decrease of V-basal (1.4-1.9 times) and V-SIR (2.1-2.8 times). It promoted a decline in t he resilience of soil systems, especially during the application of mi neral fertilizers. Deterioration of the resilience may be assessed as slight and moderate in chernozem and as moderate in soddy-podzolic soi l.