On-line version ISSN 1678-4499
Bragantia vol.29 no.unico Campinas Jan. 1970
Nutrição nitrogenada, fosfatada e potássica da batatinha, revelada pela análise química foliar*
Nitrogenous, phosphatic and potassic nutrition of potato as revealed by foliar analyses
J. Romano Gallo; Rúter Hiroce; Sylvio de A. Nóbrega
In annual crops, with short vegetative cycle as the potato (Solanum tuberosum L.), foliar analyses is very useful to establish correlations between the amount of different elements in the leaf and the yield as well as to determine the fertilization formula, most recommendded for each soil.
Foliar analyses of potato were made on samples collected from 11 field experiments, planted in 1965, in the southern (planting during the first quarter, variety "Bintje", with irrigation) and the northeastern region (planting during the third quarter variety "Aquila", without irrigation) of the State of São Paulo. The soils at the site of these experiments were classified as Ortho-Dark Red Latosol, at the southern region and Ortho-Red Yellow Latosol, Ortho-Red Yellow Podzol or Gravelly Podzol at the northeastern region. The assays followed the central composite design (Box), with five levels of N, P and K, corresponding to factorial 23, 6 axial points and one central, besides the control treatment, without fertilizer, in two replications.
Samples consisted of petioles, which were collected at 3 different stages of the plant cycle, respectively at 30, 50 and 70 days after germination, according to a previously described method (3). Determinations on the contents of soluble nitrogen, soluble phosphorus and total potassium, were made following analytical procedures published elsewhere (3, 6).
Symptoms of nitrogen and phosphorus defficiency were noticed in leaves with the lowest content of these elements. Economical dose of fertilizer for each potato variety was calculated using the formula of Pimentel Gomes and Abreu (8).
The following conclusions were obtained from the present experiment:
(a) The variety "Bintje", cultivated in a Ortho-Dark Red Latosol with irrigation, presented better yield and leaves with higher content of nutrients than the variety "Aquila", planted in a Ortho-Red Yellow Latosol, Ortho-Red Yellow Podzol and Gravelly Podzol, without irrigation.
(b) There were linear and significative effects of the nitrogenous and phosphatic fertilization on the tuber yield as well as in the amount of these elements in the leaves of both varieties.
(c) The economic mixture for fertilization, in kg/ha of N, P2O5 ana K2O were 200-300-30 for variety "Bintje" and 150-450-30, for "Aquila".
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Recebido para publicação em 29 de dezembro de 1969.
* Trabalho apresentado ao XII Congresso Brasileiro de Ciência do Solo, realizado em Curitiba, Estado do Paraná, de 14 a 26 de julho de 1969.