Abstract

BENINTENDE, María C. et al. Soil Nitrogen Supply Estimation for Rational Fertilization. Cienc. docencia tecnol. [online]. 2008, n.37, pp.141-174. ISSN 1851-1716.

Balance method applied to nitrogen fertility diagnosis needs an estimation of the quantity of N supplied by the mineralization process. From the hypothesis that the potentially mineralizable nitrogen (N₀) allows estimations of N supply therefore adjusting N fertilizer quantities, we tended to find analytical techniques to make possible speedy N₀ estimation, so that they could be used for diagnostic purposes. Seven days anaerobic incubation (N - IA) performed the best adjustment with N₀ (R² = 0.735) and will allow good N₀ estimations from N - IA values. The adjusted lineal model found was: N₀ =1.1305 N - IA + 55.275. The N₀ found in our experiments ranged from 95 to 247 mg of N kg^-1 and represented between 6 to 12% of the total N. In addition, we found that sub-superficial layers mineralized almost 43% of the quantities mineralized in the superficial one. Comparing direct drilling vs ploughed soils, we found that soil temperature in direct drilling was 2ºC lower than in ploughed soils during a maize cycle.

Keywords : Agricultural Sciences; N mineralization; Analytical techniques; N₀ estimation.

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