Authors: N V Paranychianakis M Tsiknia G Giannakis N P Nikolaidis N Kalogerakis
Publish Date: 2013/02/24
Volume: 97, Issue: 12, Pages: 5507-5515
Abstract
This study investigated the effect of municipal solid waste MSW compost 0 50 and 100 t/ha on N cycling and the microorganisms involved in it in a clayloam soil After a release of nitrates NO3 −N in the first 6 days after compost incorporation soil NO3 −N content remained constant in all the treatments until day 62 suggesting N immobilization induced by the soil used in this study Then soil NO3 −N content increased in all treatments and especially in the highest compost dose providing evidence that immobilization effect has been at least partially relieved amoA gene copies of ammoniaoxidizing archaea AOA and bacteria AOB followed the overall pattern of soil NO3 −N content however no differences were found in amoA gene copies among treatments except in the last sampling an effect attributed to the slight differences in the potential nitrification rate among them Ammonia oxidizer pattern provided evidence that both groups were involved in ammonia oxidation and changes in their abundance can be used as ‘indicator’ to predict changes in soil nitrification status Moreover the strong correlation between AOA and AOB amoA copies R 2 = 094 and the high slope 13 of the curve suggest that AOA had probably an important role on ammonia oxidation Denitrifying genes nirS nirK nosZ also followed the general pattern of soil NO3 −N and they were strongly correlated with both groups of ammonia oxidizers and particularly AOA suggesting strong interrelationships among them Losses of N through denitrification as they were estimated by total nitrogen were inversely related to soil NO3 −N content Similar to ammonia oxidizers denitrifying gene copies did not differ among compost treatments an effect that could be probably explained by the low availability of organicC in the MSW compost and hence the competition with aerobic heterotrophs
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