‘FUJI’ APPLE TREE RESPONSE TO PHOSPHORUS FERTILIZATION

Gilberto Nava,Marlise Nara Ciotta,Gustavo Brunetto

doi:10.1590/0100-29452017369

Abstract

ABSTRACT The aim of this work was to evaluate the effects of orchard fertilization with increasing rates of phosphorus (P) on yield and critical levels of P in the soil and in the leaf of ‘Fuji’ apple trees. The experiment was conducted in São Joaquim, state of Santa Catarina, southern Brazil, from 2010 to 2015, in an Inceptisol soil. The three apple orchards were planted in 2004 with the Fuji cultivar grafted on Marubakaido/ M9 rootstock and grown under a high-plant-density system (1984 trees ha-1). Annual fertilizer levels of 0, 40, 80, 120 and 160 kg ha-1 of P2O5 (as triple superphosphate) were applied to the soil surface, without incorporation, in a randomized block design with five replicates. In the first and last years (2011 and 2015), soil samples were collected from 0-10, 10-20 and 0-20 cm layers and the available P content was analyzed. Annually, whole leaves were collected and analyzed for P content. The number and weight of fruits per tree and hfruit yield were also evaluated. Application of P increased the content of available P in the soil, but this increase was not accompanied by increased leaf P content nor by increased fruit yield. This suggests that, in soils with medium to high content of organic matter and well fertilized with P before planting, there is no response of apple trees for P reapplication in the 10 subsequent years.

Highlights

In traditional apple (Malus domestica Borkh) producing countries, fertilization with phosphorus (P) in orchards has received less attention in relation to fertilization with other macronutrients, such as nitrogen (N) and potassium (K), partly due to the lower demand of P by the culture (NEILSEN; NEILSEN, 2003)
In the 1020 cm layer, there was no increase in the available P, even after five years of successive applications of P fertilization (Table 2), indicating that P is strongly retained in most superficial layer of the soil
The P forms an inner-sphere complex with functional groups of reactive soil particles, which decreases its mobility in soil solution and encourages its buildup in more superficial layers (BRUNETTO et al, 2015)

Summary

Introduction

In traditional apple (Malus domestica Borkh) producing countries, fertilization with phosphorus (P) in orchards has received less attention in relation to fertilization with other macronutrients, such as nitrogen (N) and potassium (K), partly due to the lower demand of P by the culture (NEILSEN; NEILSEN, 2003). While the ideal foliar concentrations of N and K take values between 20 to 25 and 12 to 15 g kg-1, respectively, the normal concentration of P in the leaves of apple trees is lower than 3.0 g kg-1 (CQFS-RS/SC, 2004). This does not eliminate the need for addition of P to the soil, especially in tropical and subtropical regions, where much of the P can be absorbed to the functional groups of soil colloids, which decreases its availability to plants (GUARDINI et al, 2012). P deficiency reduces root growth, causing premature leaf abscission as well as negative effects on flowering and fruiting (SUZUKI; BASSO, 2002)

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