Resumo

CRISTOBAL-ACEVEDO, D.; ALVAREZ-SANCHEZ, M. E.; HERNANDEZ-ACOSTA, E.  e  AMENDOLA-MASSIOTTI, R.. Nitrogen Concentration in Soil as Affected by Organic and Conventional Management. Terra Latinoam [online]. 2011, vol.29, n.3, pp.325-332. ISSN 2395-8030.

Currently it has been proposed that organic farming systems constitute a more sustainable option than those managed conventionally. However, to recommend these systems, it is necessary the evaluation of their potential benefits in long-term studies. In order to evaluate the effect of organic and conventional farming, on N concentrations at 0, 30, 60, 90, and 120 cm deep in soil, an experiment was conducted in plots planted with corn. The experiment was conducted during eight growing seasons. At the end of the growing seasons of 2001 and 2008 soil samples were collected at the depths above mentioned and the concentration of nitrate, ammonium, mineral N, total N and organic N were determined. The data were analyzed with a completely randomized design treatments. The advantages of the organic system after eight cycles of maize were an improvement in soil conditions in the surface layer (0 - 30 cm), increasing the organic matter concentration of 1.66 to 1.83%, a higher concentration of organic N and total N because total N reserves increased 40%, of which over 95% were organic N. The advantage of the conventional system after the same period in the cultivation of maize was an increased availability of nitrate, ammonium, and mineral N in the superficial layer (0-30 cm).

Palavras-chave : nitrates; ammonium; total nitrogen; organic nitrogen; crop residues.

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