Anais do XXXIV Congresso Brasileiro de Ciência do Solo

Fertilizer management of fruit trees: evaluation of tree nutritional status and soil fertility

MORENO TOSELLI⁽¹⁾;
1 - UNIVERSITY OF BOLOGNA;

In fruit tree fertilizer management, yearly nutrient application rate should be established according to the amount of nutrient removed, on the basis of soil nutrient availability. With regard to nitrogen (N), the fraction available for root uptake includes nitrate- and ammonium-N (Nmin). Tree mineral status is traditionally evaluated through foliar analysis. However, new strategies for earlier tree nutritional evaluation are being tested (i.e. flowers, buds and young leaves analysis). Leaf nutrient concentration must be compared to the optimum range established for each variety in the different areas of cultivation and phenological stages. Foliar applications of N are recommended early after bloom, when a high fruit set is expected, with soil low temperature and high moisture or in post harvest to promote the building of N reserves. To prevent pre- and post-harvest fruit disorders, calcium foliar application should be scheduled for apple varieties such as Fuji, Braeburn, etc. susceptible to such disorders. Late season sprays with CaCl2 are preferred to maintain the ratio K:Ca lower than 30. Index terms: ammonium-N, calcium, foliar nutrition nitrate-N, leaf analysis, nutrient use efficiency.

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