Improved tomato development by biochar soil amendment and foliar application of potassium under different available soil water contents

Abstract

The use of carbonaceous materials such as biochar has been considered an innovative solution in agriculture, especially to mitigate dry events caused by climate change. Biochar can improve water holding capacity, physical and chemical properties of soil, and increase the productivity of agricultural systems. However, underlying physiological mechanisms remain poorly understood. Mineral supplementation with potassium nitrate (KNO₃) via foliar application is another promising strategy in agricultural management under irrigation deficit. Thus, we investigated the combined effects of biochar and foliar application of KNO₃ on growth, yield, and physiology of tomato plants under different irrigation regimes. Results did not indicate a synergistic effect of biochar and foliar application of KNO₃. Biochar application alleviated tomato plant stress under deficit irrigation, with plants showing better functioning of photosynthetic apparatus, higher yield, and better fruit quality, as well as increased water use efficiency. Coffee husk biochar (K-rich feedstock) fully met the tomato plant’s demand for K and partially met the demand for some other elements (P, Mg, Fe, Zn, Mn, and Cu). Although positive effects of KNO₃ application was verified for some physiological and fruit quality components, overall, foliar application of KNO₃ did not improve tomato yield. It is concluded that biochar soil amendment can be a promising practice to increase yield and quality of tomato fruits under deficit irrigation. Therefore, biochar-based fertilizer can be an alternative K source that also provides stable carbon to soil and helps to mitigate stress caused by prolonged drought.

Keywords:

• Climate change
• drought tolerance
• pyrolysis
• vegetables

Acknowledgments

The authors would like to acknowledge Departamento de Agronomia and Programa de Pós-graduação em Fitotecnia at Universidade Federal de Viçosa (UFV), Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brasil (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG).

Authors’ contributions

Manoel Nelson de Castro Filho: Conceptualization, Methodology, Formal analysis, Investigation, Data Curation, Writing-Original Draft and Visualization: Leônidas Carrijo Azevedo Melo: Conceptualization, Methodology, Visualization, Resources, Writing - Review & Editing and Supervision. José Ferreira Lustosa Filho: Methodology, Formal analysis. Ésio de Castro Paes: Methodology, Formal Analysis and Investigation. Felipe de Oliveira Dias: Methodology, Formal analysis and Investigation. Jessica Lino Gomes: Methodology, Formal analysis and Investigation. Carlos Nick: Conceptualization, Methodology, Formal analysis, Resources, Writing - Review & Editing, Supervision, Project administration and funding acquisition.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.