TOMATO ROOT GROWTH UNDER DIFFERENT SOIL AND CLIMATE CONDITIONS

Abstract

European Community agricultural and environmental policies clearly aims at a rational use of natural resources, particularly water, and a reduction to zero in nitrogen pollution. These goals are impossible to reach without a day-by-day evaluation of the availability of water and nitrogen in the root zone. Therefore, a precise evaluation of root zone volume is essential to optimise crop water and nutrient management. A good estimation of the root zone volume requires an evaluation of the root elongation rate on three axes: depth, between rows and within rows. Horizontal root growth (between and within rows) may be assumed to be uniform and thus an uniform 3D root distribution can be calculated without taking into account differences in root density inside the root zone. Root elongation can be assessed on the basis of depth and width only. Tomato root growth rate was analysed using the data collected during the EU QUALITOM project. The project database is derived from observations made over three years in ten experimental stations located throughout the Mediterranean area and representing most of the tomato growing soil and climate conditions. Observed root growth was analysed and correlated with different soil characteristics, available water content, thermal day units accumulation, accumulated radiation and photosynthetic active radiation (PAR) in order to define some useful algorithms for modelling the soil volume occupied by roots.