Abstract

MARTINEZ, J.P; GILETTO, C.M  and  ECHEVERRIA, H.E. Nitrato en pecíolo e índice verde en estratos del canopeo del cultivo de papa. RIA. Rev. investig. agropecu. [online]. 2012, vol.38, n.2, pp.141-149. ISSN 1669-2314.

The nitrate concentration in the petiole (NDB) and green index (GI), measured at early stages of the cycle in the lower layer, may be used as an alternative to the traditional methods to evaluate nitrogen (N) nutritional status. Two experiments were carried out using the varieties of potato Innovator and Umatilla Russet during the 2006-2007 growing season. Four N treatments (N0=control; N1=62 kg ha-1; N2=125 kg ha-1 y N3=250 kg ha-1) were evaluated in each one of them. At early stages of the cycle, the NDB and the GI in upper and lower layer of the canopy were determined. These two indexes were then related to N rate and total N accumulated by the crop. The NDB determined the N nutritional status in early stages of the cycle with higher precision than GI. The response of NDB to N rate and N accumulated varied among canopy layers, being higher in the lower one. The GI was not affected by N doses or canopy layers. Therefore, the determination of GI in the lower leaves did not improve the sensibility of this diagnostic method. However, as NDB in the lower layer showed a higher sensibility to changes in N availability and total dry matter relative to the upper layer, it can be used as a promising method to diagnose N nutritional status in potato crops.

Keywords : Solanum tuberosum; Potato variety; Nitrogen.

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