MACRONUTRIENT CONCENTRATION AND CONTENT IN PASSION FRUIT LEAVES UNDER SAMPLING METHODS AND N-K FERTILIZATION RATES

Rodinei Facco Pegoraro,Victor Martins Maia,Deivisson Ferreira Da Silva,Ananias Costa Medeiros,Paulo Augusto Pereira Lopes

doi:10.1590/0100-29452017782

Abstract

ABSTRACT Nitrogen and potassium fertilization and assessment of adequate nutritional status are essential for increasing fruit production of passion fruit. However, studies related to characterization of the leaf nutrient concentration and content in passion fruit with different production capacities are scarce in the literature in Brazil. The objective of this study was to evaluate macronutrient leaf concentration and content in different parts of the reproductive shoot of yellow passion fruit subjected to different ratios of N and K fertilization. The study was conducted in a randomized block design, with three replications, following a 4 x 6 factorial arrangement consisting of four cultivars of yellow passion fruit (BRS Gigante Amarelo, IAC 275, BRS Ouro Vermelho, and BRS Sol do Cerrado) and six application rates of N-K2O fertilizer (0-0, 50-125, 100-250, 150-375, 200-500, and 250-625 kg ha-1 year-1). Two leaf sampling methods were adopted (leaf located at a position adjacent to the fruit, and leaf located at the end of the reproductive branch) for nutritional assessment. The leaf located at the adjacent position had lower N, P, K, Mg, and S concentration and higher Ca concentration than the concentrations observed in the standard leaf. However, the higher leaf dry matter in adjacent leaves resulted in increased macronutrient concentration/content. The increase in N-K fertilizations inhibited Ca and Mg content in the leaves adjacent to the fruit of the Gigante Amarelo, IAC, and Ouro Vermelho passion fruit cultivars, but did not affect Ca and Mg content in the standard leaf. The passion fruit cultivars showed different leaf nutrient contents after N-K fertilization, indicating variable nutritional demands and the need for specific diagnostic methods for each cultivar.

Highlights

Passion fruit (Passiflora edulis) is a fruit-bearing plant of great economic and social importance for Brazil, which is the largest producer and consumer of its in natura and processed fruit juice in the world
According to the results obtained after analysis of variance, the production of dry matter weight of the leaves and the leaf concentrations and content of N, P, K, Ca, Mg, and S were significantly affected (p
In the adjacent leaf of the cultivars Ouro Vermelho and Sol do Cerrado, an increase was found in the content of dry matter weight with the increase in the N-K application rate up to 150375 and 128-319 kg ha-1, respectively (Figure 1)

Summary

Introduction

Passion fruit (Passiflora edulis) is a fruit-bearing plant of great economic and social importance for Brazil, which is the largest producer and consumer of its in natura and processed fruit juice in the world. In 2014, the cultivated area for this plant in Brazil was 57,183 ha, obtaining production of 823,284 t of fruit and mean yield of 14.5 t ha-1 (IBGE, 2016). This production is very dependent on balanced fertilization and adequate leaf nutrient concentrations. N deficiency in passion fruit plants leads to generalized chlorosis and early leaf drop, flowers with light red color, and light yellow fruits with a translucent appearance (FREITAS et al, 2011)

Objectives

Methods

Results

Conclusion