A three-year
field experiment in a winter wheat–rice cropping system was performed to compare the
influence on soil microbial parameters including microbial activity, abundance and community by heavy
application of manure-based compost (CP) and inorganic nitrogen (CF, inorganic nitrogen applied as
urea). The same amount of total nitrogen that was calculated from the local farming habits was applied in
each season for the two treatments. Samples were analyzed after the third season of wheat harvested. In
contrast to the untreated control (CK), CP and CF treatments both significantly increased the soil nutrient
content (p < 0.05) with converse results obtained for improvements in soil water-holding capacity and
acidification. Heavy application of organic compost markedly increased the soil microbial activity and
gene copies of bacteria, archaea, and ammonia-oxidizing bacteria (AOB). However, pyrosequencing
results demonstrated that heavy application of inorganic nitrogen had no influence on soil bacterial
diversity. Diversity was significantly decreased by organic compost. Changes occurred in the bacterial
community composition in compost treated soils, and most abundant taxa correlated with the moisture
content, pH, organic C, total N, available P, and available P. The
findings of this study indicated that
compost application was not always beneficial to soil quality, and might decrease soil diversity.
Therefore, studies to maintain the relationship between compost application rate and microbial diversity
should be further conducted to protect soil ecosystems against disturbances