Sustainable management tools for sorghum cultivation in the second harvest in Western São Paulo: Use of amino acids and humic substance-based biostimulants

• Grant number: 24/17157-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2024
• End date: November 30, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Fernando Shintate Galindo
• Grantee: Eduardo Hernandes Ferrari
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil

Abstract

Sorghum cultivation has been an excellent option for situations where water deficits and low soil fertility conditions pose greater risks for other second-crop systems, such as maize cultivation in high-risk regions like the western part of São Paulo. Additionally, sorghum cultivation has contributed to offering multiple uses, including human food, animal feed, and bioenergy production. However, in modern agriculture, reducing environmental impact while ensuring high grain yields and superior product quality is a primary goal. To avoid excessive use of external inputs without compromising crop performance, it is essential to seek increased nutrient availability in the soil and greater water and nutrient use efficiency for sustainable agricultural production. Biostimulants used in agriculture consist of organomineral substances and/or microorganisms aimed at enhancing plant growth and development, and they can be a viable option to mitigate the negative effects of water and thermal stress in sorghum cultivation. The adoption of technologies and products with biostimulant, biopromoter, or abiotic stress-reducing effects is promising, particularly due to their potential to promote root and shoot growth, offering potential benefits to the crop. The objective of this proposal is to evaluate the effect of different forms and timing of the application of a biostimulant based on amino acids and humic substances on sorghum physiology (gas exchange parameters and ICF), nutrition (N accumulation in the shoot, root, straw, and sorghum grains), growth, development (key 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 follow a randomized block design with four replications, containing six treatments: 1) control - no biostimulant application; 2) 200 mL ha-1 of a biostimulant product based on amino acids and humic substances applied to seeds + 300 mL ha-1 sprayed via foliar application at V4 (4 fully developed leaves) + 300 mL ha-1 via foliar application at booting stage (pre-flowering); 3) 800 mL ha-1 applied at V2 (2 fully developed leaves); 4) 800 mL ha-1 applied at V4; 5) 400 mL ha-1 applied at V4 + 400 mL ha-1 applied at booting stage; 6) 800 mL ha-1 applied at booting stage. The following parameters will be evaluated: leaf chlorophyll index (LCI), gas exchange parameters (IRGA), dry mass and nitrogen (N) accumulation in shoots and roots at full flowering of sorghum (stage 6), dry straw mass, production components, grain yield at the end of the cycle (stage 9), as well as N accumulation in straw and grains.