Common bean irrigation management using spectral indices

• Grant number: 24/15868-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Agronomical Sciences - Agricultural Engineering - Soil and Water Engineering
• Principal Investigator: Anderson Prates Coelho
• Grantee: Rafael Henrique Dias Silva
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Optimizing water use in agriculture is one of the main global concerns. With the advent of digital agriculture, several techniques are available for this purpose, requiring validation. The aim is to compare the real-time irrigation management of common bean based on the NDVI, leaf chlorophyll index (LCI) and soil cover fraction (CF) spectral indices, aiming to apply them in variable rate irrigation (VRI) management, and indicate the most robust index for this strategy. The experiment will be carried out in the 2025 winter harvest, in a central pivot area with VRI application. Based on data from common bean experiments conducted between 2019 and 2023, models (regressions) were adjusted to estimate the crop coefficient (Kc) of the crop based on NDVI, FC and LCI. Once you have the calibrated models, five irrigation management treatments will be allocated. The experiment will be allocated in a randomized block design, with four repetitions. The treatments will be: Standard irrigation management adopting the tabulated Kc values, according to the FAO 56 method (Treat 1); Irrigation management through monitoring of soil moisture measured by a soil sensor (Treat 2); Irrigation management using NDVI to estimate Kc values for common bean (Treat 3); Irrigation management using FC to estimate Kc values (Treat 4); Irrigation management using the LCI to estimate Kc values (Treat 5). Irrigation management will be with a fixed irrigation shift and variable depth, with irrigation carried out on Tuesdays and Fridays. Throughout the common bean cycle, spectral indices and soil moisture will be evaluated. The following will also be evaluated: aboveground dry mass, yield components, grain yield and water productivity. The data will be subjected to analysis of variance (F test) and comparison of means (Tukey).