Nutritional diagnosis and fertilization with boron and zinc in \'Hass\' avocado (Persea americana Mill.)

• Ano de defesa: 2025
• Autor(a) principal: Oliveira Junior, Marcelo Almeida de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Avocado cultivation; CND; Cultivo de abacate; DRIS; Manejo nutricional; Nutrient management
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/11/11136/tde-07042025-102817/

The avocado (Persea americana Mill.) has seen significant growth in global production and cultivated areas in recent years, driven by increasing demand for its fruits due to their health benefits. The \'Hass\' cultivar is the most widely produced avocado worldwide and has gained prominence in Brazil as a key export product to non-producing countries. Despite this potential, limited information on nutritional management for seedlings and orchard production constrains the crop\'s potential. This study aimed to establish nutritional standards for \'Hass\' avocado seedling production and productive-age commercial orchards by applying the Diagnosis and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) methodologies, as well as to evaluate the effects of boron and zinc fertilization on plant growth and production. First, nutritional standards were established for nursery seedlings, generating Sufficiency Ranges (SR) and Critical Levels (CL) to guide nursery growers in nutritional management improving seedling quality production. Both DRIS and CND proved effective, with CND showing superior accuracy in explaining seedling productivity variations. Second, SR and CL were generated for avocado orchards, stratified by plant age (49 years and 1026 years). While DRIS was effective for younger plants, CND demonstrated utility across both groups and better explained yield variations. Finally, the effects of boron and zinc fertilization were assessed, with soil and foliar applications. However, boron and zin did not enhance plant growth or yield and, in some cases, negatively affected root characteristics, fruit number, and productivity, likely due to toxicity. Soil fertilization increased boron content in fruits and accelerated ripening, which was associated with higher boron levels in the fruit.