The contents of NO3-, NH4+ and mineral N (NO3- + NH4+) in a soil cultivated with tomato crop, in response to nitrogen doses and organic fertilization were evaluated in a field experiment conducted during the autumn/spring season (from May to Oct. 1999) and installed at 'Horta do Fundão' of Federal University of Viçosa, in a Cambic Red-Yellow Argisol. The N doses applied were 0, 110, 220, 440 and 880 kg ha-1 and the organic matter doses in the form of decomposed bovine manure were 0 and 8 t ha-1 (dry weight basis). The experiment was conducted in a randomized block design arranged in a 5 x 2 factorial, with four replications. Soil samples were collected from the 0-20, 20-40 and 40-60 cm depths at the end of the plant cycle. In all depths and in the two doses of organic matter, the NO3- and NH4+-N contents increased with the increament of N doses, and the NO3--N contents were more influenced by this increase than NH4+-N contents. The responses presented by mineral N contents were similar to those presented by NO3--N contents.
Lycopersicon esculentum; nitrogen fertilization; bovine manure
