Several studies have indicated that intensive tillage has notable effect on properties of the soil microbiota that may influence numerous important soils functions, e.g. mobilization of nutrients or change of the overall emission rates of greenhouse gases. Therefore, the aim of our study was to investigate dynamic of microbial communities in soil planted with soybean under different tillage systems. Moreover, abundance of populations harboring the nitrous- oxide reductase gene (nosZ) as an indicator for potential shift s in N2O emission rates was studied. The study was established at chernozem soil of Northern Baranja region in Republic of Croatia as completely randomized block design of four replicate plots for each tillage system in three years experiment. The soil was managed as followed: CT - conventional tillage (moldboard ploughing at 25-30 cm depth), DH - multiple discs harrowing (10-15 cm depth), and NT – no-tillage system. Soil samples were collected in summer and autumn in year 2003. Our results suggested that the reduction of tillage had no effects on the bacterial community structure. This might be a result of the very dry climatic conditions at the investigated site and /or a result of plant species effect (soybean). Slight effects of the tillage management became visible at least when samples were taken in autumn for microbes harboring the N2O reductase gene, indicating that there might be shift s in denitrification pattern in response to changes in tillage practice.

soil microbiota, tillage, soybean, denitrification

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia