Resumo

BONELLI, Lucas Emmanuel; SAINZ ROZAS, Hernán René; ECHEVERRIA, Hernán Eduardo  e  BARBIERI, Pablo Andres. Nitrogen source and application time for no-till maize in Balcarce. Cienc. suelo [online]. 2018, vol.36, n.1, pp.88-98. ISSN 1850-2067.

Nitrogen (N) fertilization after maize (Zea mays L.) emergence contributing to synchronize N supply with plant N demand. However under no-tillage management this practice can increase ammonia (NH₃) volatilization losses, reducing N-recovery efficiency (NRE) and crop yield. The objective of this work was to evaluate the effect of N-sources (with different NH₃ potential loss) applied at different times, on NRE and crop yield. Two no-till maize field experiments were conducted at Balcarce (37º 45' S, 58º 18' W; 130m ASL) on a soil complex of Typic Argiudoll and Petrocalcic Paleudoll during two growing seasons. Treatments consisted in a single broadcast application of 80 kg N ha^-1 from four N-sources (urea, UAN , UAN +T and CAN) at three different developmental stages of crop (Sowing, V₆ and V₁₀). There was no difference on NRE and crop yield when N applications were delayed from sowing to V₆ and V₁₀. In addition, N-sources with less NH₃ volatilization potential did not show better performance than urea. This behavior was consequence by the occurrence of rainfall events that incorporated N into soil depth. These results suggest that under these soils and climate conditions, N-fertilization can be delayed for no-till corn, without affecting nitrogen crop status during the critical period, even when N-sources like urea are used.

Palavras-chave : volatilization; N recovery efficiency.

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