Fate of the nitrogen from fertilizers in field-grown maize.

RIMSKI-KORSAKOV H; RUBIO G,; LAVADO RS

NUTRIENT CYCLING IN AGROECOSYSTEMS

SPRINGER

Lugar: Berlin; Año: 2012 vol. 93 p. 253 - 263

1385-1314

The nitrogen (N) from fertilizers hasdifferent fate, some of which affect the environmentor the human health, e.g. nitrates in groundwater. Wedetermined the fate (plant organs, soil organic matter,remaining nitrates and volatilization) of the N appliedto field-grown direct drilling maize. An experimentwas carried out in a Typic Argiudoll at Chivilcoy,Argentina (358020S, 608060W). Treatments were:control; 70; 140 and 250 kg N ha-1. Microplots werefertilized with urea tagged with 15N (1.5 % abundance).Plant biomass and N concentration weredetermined at flowering and at physiological maturity.Soil organic N (0–30 cm) and nitrates and ammoniacalN concentrations (0–300 cm) at harvest, andammonia volatilization were determined. 15N wasdetermined in all samples. The crop was the main sink,recovering an average of 56 % of the N from thefertilizer. Both the soil organic fraction and ammoniavolatilization were the second N sink. The N remainingas residual nitrates averaged 8.6 %and the leachednitrates were only 0.8 % of the fertilizer applied. MostN leached after maize cropping could be accredited tomineralization of organic N. Organic matter could then be a temporary sink, which reduces N leachingfrom a single fertilization but releases nitrates thefollowing years