Nitrogen dynamics in soil management systems. I - flux of inorganic nitrogen (Nh4 + and N-NO3 -) [Dinâmica do nitrogênio em sistemas de manejo do solo. i- fluxo do nitrogênio inorgânico (nh 4 + and N-NO3 -)]
de Moraes Sa J.C.,State University of Ponta Grossa |
de Oliveira Ferreira A.,Federal University of Santa Maria |
Santos J.B.,Federal University of Paraná |
Massinham A.,Agronomic Engineer at the UEPG |
And 6 more authors.
Revista Brasileira de Ciencia do Solo | Year: 2011
In agricultural systems the N-NH4 + and N-NO3 - contents is significantly affected by soil management. This study investigated the dynamics of inorganic nitrogen (N; 4 + and N-NO3-) in an experimental evaluation of soil management systems (SMSs) adopted in 1988 at the experimental station of the ABC Foundation in Ponta Grossa, in the Central South region of the State of Paraná. The objective of this study was to evaluate the changes in N-NH4 + and N-NO3 - flux in the surface layer of a Red Latosol arising from SMSs over a 12-month period. The experiment was arranged in a completely randomized block design in split plots, in three replications. The plots consisted of the following SMSs: 1) conventional tillage (CT); 2) minimum tillage (MT); 3) no-tillage with chisel plow every three years (NTCH); and 4) continuous no-tillage (CNT). To evaluate the dynamics of inorganic N, the subplots represented samplings (11 sampling times, T1 - T11). The ammonium N (N-NH4 +) and nitric N (N-NO3 -) contents were higher in systems with reduced tillage (MT and NTCH) and without tillage (CNT) than in the CT system. In the period from October 2003 to February 2004, the N-NH4 + was higher than the N-NO3 soil content. Conversely, in the period from May 2004 to July 2004, the N-NO3 - was higher than the N-NH4 + content. The greatest fluctuation in the N-NH4 + and N-NO3 - contents occurred in the 0-2.5 cm layer, and the highest peak in the N-NH4 + and N-NO3 - concentrations occurred after the surface application of N. Both N-NH4 + and NNO3 - were strongly correlated with the soil organic C content, which indicated that these properties vary together in the system.