Resumo

COPPERI, MZ; MANDOLESI, ME; CANTAMUTTO, MA  e  RON, MM. Comparative effectiveness of two nitrogen sources for corn fertilization. Phyton (B. Aires) [online]. 2013, vol.82, n.1, pp.99-106. ISSN 1851-5657.

Corn has not only a high growth potential and a great capacity of biological response to suitable crop management but also may contribute to a better match of crops with environmental offer in Argentina. Nitrogen (N) fertilization must make provision for eventual N losses, and fertilization strategies must be designed so as to minimize their global incidence. The diferent quick-release N sources show similar efciencies when they are incorporated, but in surface applications, sources that contain little or no amidic N have a better performance than urea (U). The objective of this paper was to make an evaluation of corn response to N applied in V6 without incorporation, using two different solid N sources. A field experiment was carried out during 2004, in a farm located 30 km away from General Pico (La Pampa, Argentina), to evaluate corn response to N rates (0 - 120 kg/ha) sidedressed in V6 without incorporation, using U or a commercial mixture of ammonium nitrate and dolomite (ND). Rainfall and temperatures were ideal during the crop cycle. The excellent growing conditions reflected in high corn yields. The results showed that N fertilization afected virtually all yield components. Yield was on average 2417 kg of grain/ha greater in the ND than in the U treatments. For a N rate below 85 kg/ha, agronomic efficiency was of 65 and 87 kg of corn per kg of applied N for U and ND, respectively. Apparent fertilizer N recovery was 1.14 and 1.34 kg absorbed N per kg applied N for U and ND, respectively. For the kind of soil, cultivar and growing conditions of the experiment, a substitution value of 1.6 can be used to estimate ND-N rates from models developed for U-N.

Palavras-chave : Fertilizer technology; Nitrogen recovery; Substitution value.

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