Resumen

ORTEGA B., Rodrigo  y  MARDONEZ O., Rogelio. Spatial Variability of Nitrogen Mineralization in a Volcanic Soil of Ñuble Province, VIII Region, Chile. Agric. Téc. [online]. 2005, vol.65, n.2, pp.221-231. ISSN 0365-2807.  http://dx.doi.org/10.4067/S0365-28072005000200012.

The objective of this study was to characterize the spatial variability of N mineralization in a volcanic soil, corresponding to a mix of the Bulnes and Arrayan series (Typic Distrandept) of Ñuble Province, Chile, to determine the potential of site-specific N management from the soil N-supply standpoint. Intact soil samples, georeferenced with a differential global position system (DGPS) contained in PVC tubes (5 cm diameter by 12 cm length), with bags containing ion exchange resins were incubated in situ. The amounts of NO₃-N plus NH₄-N extracted from the soil were added to those extracted from the resin bags to determine N mineralized during the incubation periods. To determine NO₃-N, a methodology was adapted from Self and Rodriguez (1998). Through the use of geostatistical tools it was possible to adequately map the spatial variability of mineralized N in the two evaluation periods, as well as the total interval studied. Future studies of in situ N mineralization, for similar soils, should consider sampling intensities between 5 to 35 points ha^-1, to assure spatial dependence.

Palabras clave : N mineralization; spatial autocorrelation; exchange resins; inorganic N analysis.