Crop Growth and Two Dimensional Modeling of Soil Water Transport in Drip Irrigated Potatoes.

Drip irrigation can be an effective way to improve water and nitrogen use efficiency in soil and hence to reduce the environmental pollution. In the EU project SAFIR (www.safir4eu.org) a potato experiment was carried out in lysimeters on three different soil types: coarse sand, loamy sand and sandy loam. An automatic roof was used to exclude the lysimeters from natural precipitation. The potatoes were drip irrigated following different strategies: Fully irrigated (FI), deficit irrigation (65% FI), and partial root zone drying (PRD). Gas exchange measurements were carried as well as sampling of abscisic acid (ABA). Model outputs from the mechanistic simulation model Daisy, in SAFIR developed to include 2D soil processes and gas exchange processes based on Ball et al. and Farquhar were compared with measured crop dynamics, final DM yield and volumetric water content in the soil measured by TDR probes. The probes were installed parallel to the tillage direction at different positions in the potato ridge. The new Daisy 2D model showed to be able to simulate crop growth, water use and soil water distribution fairly well.