Calibration of a transpiration reduction model by thermometric and isotopic methods and its application for yield prediction in intercropping systems

• Grant number: 15/21716-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2016
• End date: January 31, 2019
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Quirijn de Jong van Lier
• Grantee: Victor Meriguetti Pinto
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 16/22874-0 - Calibration of a transpiration reduction model by thermometric and isotopic methods and its application for yield prediction in intercropping systems, BE.EP.PD

Abstract

The intercropping cultivation of maize with brachiaria is a successful management practice for the dry period of the year. The proposed research project aims to evaluate crop water stress and simulate water using by both maize and brachiaria in monocropping and intercropping plots. An isotopic method for quantification of carbon-13 (13C) and a conventional thermometric methodology will be employed for measuring plant water stress. Water use efficiency by plants in intercropping and monocropping systems will be evaluated by 13C discrimination values and dry matter measurements. Plant water stress will be associated to soil pressure head and a critical pressure head value necessary for the studied plant transpiration reduction model will be established. The agrohydrological model SWAP will be adapted for simulating crop interaction and water sharing in intercropping systems. Crop interactions and intercropping water balance simulations will be based on results of horizontal water movement between soil-plant modules and the reduction of solar radiation over brachiaria due to shading by maize plants. The introduction of Brachiaria in intercropping systems with maize can impose additional water stress on maize plants, to be quantified in this study as function of soil hydraulic properties and climate conditions. SWAP will be used to describe the general processes of the water cycle, relative plant productivity and development in intercropping. An efficient simulation of intercropping with SWAP, an objective of this study, will be an important result for agronomic modeling research.