Brazil-nut shell biochar optimizes nursery media and planting-stock quality in Euterpe precatoria under contrasting fertilization regimes

Conceição Paula Bandeira Rufino; Romeu de Carvalho Andrade Neto; Aureny Maria Pereira Lunz; Cleyton Silva de Araújo; Sebastião Elviro de Araújo Neto; Jennyfer Tamara de Lima Barbosa; Fernando Pretti Rimério

doi:10.53661/1806-9088202650264036

Authors

Conceição Paula Bandeira Rufino Universidade Federal do Acre, Doutora em Produção Vegetal, Rio Branco, Acre, Brasil https://orcid.org/0000-0003-1685-744X
Romeu de Carvalho Andrade Neto Empresa Brasileira de Pesquisa Agropecuária - Embrapa Tabuleiros Costeiros, Aracaju, Sergipe, Brasil https://orcid.org/0000-0002-8238-7020
Aureny Maria Pereira Lunz Empresa Brasileira de Pesquisa Agropecuária - Embrapa Acre, Rio Branco, Acre, Brasil https://orcid.org/0000-0003-2697-7509
Cleyton Silva de Araújo Universidade Federal do Acre, Doutor em Produção Vegetal, Rio Branco, Acre, Brasil https://orcid.org/0000-0001-9273-7322
Sebastião Elviro de Araújo Neto Universidade Federal do Acre, Centro de Ciências Biológicas e da Natureza, Rio Branco, Acre, Brasil https://orcid.org/0000-0002-1212-4989
Jennyfer Tamara de Lima Barbosa Universidade Federal do Acre, Programa de Pós-Graduação em Ciência, Inovação e Tecnologia para a Amazônia, Rio Branco, Acre, Brasil https://orcid.org/0009-0003-9063-4508
Fernando Pretti Rimério Empresa Brasileira de Pesquisa Agropecuária - Embrapa Acre, Rio Branco, Acre, Brasil https://orcid.org/0009-0001-8166-3038

DOI:

https://doi.org/10.53661/1806-9088202650264036

Keywords:

Amazonian agro-industrial residues, Plant nutrition, Seedling production

Abstract

Biochar offers a practical circular-economy strategy to improve nursery substrates and nutrient use efficiency, but optimal rates and their interaction with fertilization remain species-specific. This study evaluated the effects of six proportions of Brazil-nut shell biochar (0, 10, 20, 30, 40, and 50% v/v) and two fertilization regimes on substrate physicochemical properties and the nursery performance of Euterpe precatoria. The experiment was conducted in a randomized complete block design in a 6 × 2 factorial arrangement, with three replicates and eight plants per plot. Seedling height, stem diameter, leaf number, biomass partitioning, SPAD chlorophyll index, and Dickson Quality Index (DQI) were analyzed by two-way ANOVA, polynomial regression, and multivariate factor analysis. The biochar × fertilization interaction was significant for shoot dry mass, root dry mass, total dry mass, SPAD index, and DQI, but not for height, stem diameter, or leaf number. Conventional NPK plus micronutrients generally outperformed controlled-release fertilizer. Intermediate biochar proportions (20–30% v/v) provided the best overall nursery performance, particularly under conventional NPK fertilization. Under this regime, the highest seedling quality was achieved at intermediate biochar proportions, with DQI reaching 3.45 at approximately 20% biochar and SPAD values approaching 49 at approximately 28%. These results indicate that incorporating 20–30% (v/v) Brazil-nut shell biochar into a commercial substrate, combined with conventional NPK fertilization, is an effective strategy for producing vigorous Euterpe precatoria seedlings while valorizing abundant Amazonian agro-industrial residues.

Keywords: Amazonian agro-industrial residues, Plant nutrition, Seedling production