Spatial variations in soil water balance at field and regional scale and their implications for crop water availability and irrigation demand

• Grant number: 13/25917-4
• Support Opportunities: Scholarships abroad - Research
• Start date: June 08, 2014
• End date: January 30, 2015
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Quirijn de Jong van Lier
• Grantee: Quirijn de Jong van Lier
• Host Investigator: Ole Wendroth
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: University of Kentucky (UK), United States

Abstract

The root water uptake sink term is one of the most important components of the soil water balance. Soil hydraulic properties play a key-role when estimating this sink term on a physical basis, and its understanding is essential to assess crop water availability and irrigation demand and management. This research project aims to establish a link between spatial variability of soil hydraulic properties and crop water availability. The specific objectives are to derive field-scale characterization of soil hydraulic properties, to predict crop water stress and yield as a function of spatial variability using specific transpiration reduction functions, to use modeling and measuring to show the relation between soil hydraulic properties and soil water regime, and to develop an approach for upscaling local soil information about water content and irrigation needs to a larger regional scale. The research will focus on a 20 ha producer's field in West Kentucky cropped with maize. Rainfall and irrigation will be measured in situ; further meteorology data will be used from a nearby station. At ten observation locations in this field the soil will be hydraulically characterized and soil water content, root length distribution, leaf area index and above-ground dry mass will be monitored during the growing season. Two transpiration reduction functions, a mechanistic and empirical one, will be evaluated using the experimental observations of soil water content. The correlation between the observed time series of surface soil water content, specific soil hydraulic properties and observed yields will be analyzed. Based on the known relationship between soil water content after a rainfall period and specific hydraulic properties, an approach will be developed and evaluated to upscale local soil information to a larger regional scale using available remote sensing information.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

VAN LIER, QUIRIJN DE JONG; WENDROTH, OLE; VAN DAM, JOS C.. Prediction of winter wheat yield with the SWAP model using pedotransfer functions: An evaluation of sensitivity, parameterization and prediction accuracy. Agricultural Water Management, v. 154, p. 29-42, MAY 31 2015. (13/25917-4)