Forms and timing of application of amino acids and humic substance-based biostimulants on the physiology, nutrition, growth, and yield of maize crops

• Grant number: 24/17165-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Fernando Shintate Galindo
• Grantee: Gabriel Gomes Mozzini
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil

Abstract

Maize is one of the most widely produced crops in Brazil and worldwide, due to its versatility in both animal and human consumption. The search for sustainable strategies to mitigate the negative effects of abiotic stress conditions related to climate adversities, combined with low-fertility soils and organic matter, common in tropical regions such as the Western Paulista region, has led to the development of products that act on the physiological management of plants. These products enhance water and nutrient absorption, aiming to promote greater tolerance and plant growth under adverse conditions. Biostimulants used in agriculture are composed of organomineral substances and/or microorganisms that aim to increase plant growth and development and may be a viable option to mitigate the negative effects of water and thermal stress in maize crops. The adoption of technologies and products that have a biostimulant, biopromoting, or stress-mitigating effect is promising, especially due to their potential to promote root and shoot growth, with possible benefits for the crop. The objective of this proposal is to evaluate the effect of different application methods and timings of an amino acid and humic substance-based biostimulant on maize physiology (gas exchange parameters and chlorophyll fluorescence index), nutrition (N accumulation in shoots, roots, stover, and grains), growth, development (main biometric and productive components), and yield. The research project will be conducted under field conditions in the municipality of Dracena, SP, in a typical sandy-textured Ultisol. The experiment will be conducted in a randomized block design with four replicates, comprising six treatments: 1) control - no biostimulant application; 2) 800 mL ha-1 of a biostimulant product based on amino acids and humic substances, sprayed foliarly at V2 stage (2 fully developed leaves); 3) 800 mL ha-1 at V4 stage (4 fully developed leaves); 4) 800 mL ha-1 at V6 stage (6 fully developed leaves); 5) 400 mL ha-1 at V4 + 400 mL ha-1 at V6; 6) 800 mL ha-1 at V8 stage (8 fully developed leaves). The following will be evaluated: chlorophyll index (SPAD), gas exchange parameters (IRGA), dry matter, and nitrogen (N) accumulation in shoots and roots at the beginning of maize flowering (R1), and dry matter of stover, production components, and grain yield at the end of the cycle (R6), as well as N accumulation in stover and grains.