Marina Zanardo, Riccardo Rosselli, Andrea Meneghesso, Gaurav Sablok, Piergiorgio Stevanato, Adriano Altissimo, Lisanna Perserico, Valentina Dezuani, Giuseppe Concheri, Michael Schloter, Andrea Squartini
Abstract
Organic fertilizers are of high interest in agriculture as they promise a retarded release of the nitrogen to
soil, which improves uptake efficiency by plants and reduces negative impacts like the formation of
nitrate by nitrifiers or N2O by denitrifying microorganisms. In this study we tested the effects of seven
different commercially available organic fertilizers of plant-, animal-, or microbial origin in a two-month
greenhouse trial, using the perennial grass Cynodon dactylon in pots and monitoring effects on plant
growth as well as on the abundance of prokaryotic nitrifiers and denitrifiers by realtime PCR. In most
cases a single application of the fertilizers induced plant growth but did not increase the abundance of
nitrifiers and denitrifiers. In contrast a repeated application stimulated, in addition to plant growth, also
the increase of the two functional groups studied and a faster mobilization of nitrogen from the different
fertilizers. Upon analyzing total bacterial DNA extracted from soil nirK abundance was found responsive
to plant presence. Bacterial amoA and nosZ gene copies were significantly positively correlated with plant
growth and cumulative dry weight at harvest. The latter was responsive as early as 9 days after fertilizer
supplementation.
FOR MORE INFORMATION ON THIS TOPIC CONTACT THE AUTHOR OF THE PUBLICATION:
Adriano Altissimo
