Massimo Zilio1, Silvia Motta2, Fulvia Tambone1, Barbara Scaglia1, Gabriele Boccasile3, Andrea Squartini4, Fabrizio Adani1. 1. Gruppo Ricicla labs., DiSAA, Università degli Studi di Milano, Milan, Italy. 2. Ente Regionale per i Servizi alla Agricoltura e alle Foreste, Regione Lombardia, Milan, Italy. 3. DG Agricoltura, Regione Lombardia, Milan, Italy. 4. DAFNAE, Università degli Studi di Padova, Agripolis, Padua, Italy.
Abstract
Nitrogen transformation in soil is a complex process and the soil microbial population can regulate the potential for N mineralization, nitrification and denitrification. Here we show that agricultural soils under standard agricultural N-management are consistently characterized by a high presence of gene copies for some of the key biological activities related to the N-cycle. This led to a strong NO3- reduction (75%) passing from the soil surface (15.38 ± 11.36 g N-NO3 kg-1 on average) to the 1 m deep layer (3.92 ± 4.42 g N-NO3 kg-1 on average), and ensured low nitrate presence in the deepest layer. Under these circumstances the other soil properties play a minor role in reducing soil nitrate presence in soil. However, with excessive N fertilization, the abundance of bacterial gene copies is not sufficient to explain N leaching in soil and other factors, i.e. soil texture and rainfall, become more important in controlling these aspects.
Nitrogen transformation in soil is a compn>lex process and the soil microbial popn>ulation can regulate the potential for N mineralization, nitrification and denitrification. Here we show that agricultural soils under standard agricultural N-management are consistently characterized by a high presence of gene copn>ies for some of the key biological activities related to the N-cycle. This led to a strong n>an class="Chemical">NO3- reduction (75%) passing from the soil surface (15.38 ± 11.36 g N-NO3 kg-1 on average) to the 1 m deep layer (3.92 ± 4.42 g N-NO3 kg-1 on average), and ensured low nitrate presence in the deepest layer. Under these circumstances the other soil properties play a minor role in reducing soil nitrate presence in soil. However, with excessive N fertilization, the abundance of bacterial gene copies is not sufficient to explain N leaching in soil and other factors, i.e. soil texture and rainfall, become more important in controlling these aspects.