Carbon nanoparticle addition to fertilizers as a strategy to improve lettuce yields and nitrogen use efficiency while reducing nitrate leaching

• Grant number: 23/00349-5
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: May 01, 2023
• End date: August 31, 2023
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Thiago Assis Rodrigues Nogueira
• Grantee: Isabella Silva Cattanio
• Supervisor: Arun Dilipkumar Jani
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil
• Institution abroad: California State University, Monterey Bay (CSUMB), United States
• Associated to the scholarship: 22/05175-2 - Residual effect of sewage sludge-based organomineral fertilizer application on maize crop grown in the Cerrado region, BP.IC

Abstract

The large amounts of nitrogen (N) fertilizer used to sustain lettuce (Lactuca sativa L.) production in the Salinas Valley pose a threat to coastal and groundwater resources. To address water quality concerns, the Central Coast Regional Water Quality Control Board recently adopted Ag Order 4.0, which places a limit on N loading from agricultural operations and will require growers to reduce N application rates and improve N use efficiency (NUE) over time. Strategies that are commonly recommended to mitigate N losses, such as the use of cover crops and conservation tillage, are often difficult to incorporate into the intensive lettuce production systems of the Salinas Valley. The use of carbon nanoparticles (CNPs) as a fertilizer additive is a nondisruptive N management tool that has been shown to improve yields and NUE, while reducing nitrate leaching for several crops; however, its effectiveness in lettuce production on Salinas Valley soils has not been investigated. Recent advances in CNP manufacturing have drastically reduced production costs and have addressed previous health and environmental concerns associated with CNPs, making this technology worthy of investigation in Salinas Valley leafy green production. Our research objectives are to (1) evaluate the impact of CNP addition to fertilizer on lettuce yields and NUE, and (2) Compare nitrate leaching from soils planted to lettuce and containing fertilizer amended with or without CNPs. We hypothesize CNP addition to fertilizers will increase lettuce yields and NUE, while reducing nitrate leaching. Two greenhouse experiments are proposed in which eight treatments consisting of different CNP application rates will be tested using a completely randomized design. The same treatments will be compared in each experiment, but soils with different textures and nitrate leaching potential will be used. A decomposed granite soil from the east Salinas Valley will be included in the experiment. Data collected will include lettuce yields, NUE, nitrate leaching, soil inorganic N content, and leaf and root tissue N content. From this research, we will identify CNP application rates that optimize yield and NUE, while minimizing nitrate leaching on Salinas Valley soils. Our long-term goal is to use findings from these experiments to inform future research decisions for additional experiments using other soil textures as well as field studies that explore the use of CNPs as a N management tool in the Salinas Valley region. (AU)