A análise foliar na nutrição do milho. I - Resultados preliminares

Leaf analysis in corn plant nutrition I - Preliminary results

A análise foliar na nutrição do milho. I — Resultados preliminares

Leaf analysis in corn plant nutrition I — Preliminary results

J. Romano Gallo; Fernando A. S. Coelho; Luiz T. de Miranda¹

SUMMARY

A research aiming to establish the nutrient standards in leaves for corn through experiments conducted in the field was begun in 1962. The relations between leaf composition and yield were studied in 6 fertilizer experiments of a typical central composite design (Box). In these trials fertilizers were supplied at the rates of 0, 30, 60, 90 and 120 kg/ha of each N and P₂O₅, and 0, 15, 30, 45 and 60 kg/ha of K₂0. One sixth of the total doses of nitrogen was given at planting time, the remaining topdressed when the plants were 40-50 days old. Plots with and without sulfur were also included in order to estimate sulfur response. All treatments were carried out in two replications. Leaf samples for analysis were taken 60 days after planting (about 15 leaves per plot), according to the technique described earlier (²), that is, the fourth leaves indicated as leaf of position, +4 (Kuijper number) were collected and analyses carried out on the basal third section of the leaf-blades with the midribs stripped off.

The results showed a close connection between the mineral content of the leaves and yield (See Figures 1, 2 and 3). In each case per cent corn yield (grain) is plotted against nutrient concentration on the dry basis. Data on table 1 show the yield response observed for sulfur and the sulfate-sulfur content in the leaves. The yields obtained on the no-sulfur treatment were lower in both locations as presented. Levels of 2.80% nitrogen, 0.195% phosphorus, 2.12% potassium and 210 ppm sulfate-sulfur are probably near the boardline between deficiency and adequacy for corn.

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Recebida para publicação em 23 de março de 1965.

1

Parte de plano de trabalho feito com o auxílio da Fundação de Amparo à Pesquisa do Estado de São Paulo.

Datas de Publicação

• Publicação nesta coleção
  22 Fev 2010
• Data do Fascículo
  1965