Alternate wetting and drying of the rice crop in Northeast Spain (Ebro Delta region)"
Dr Maite Martínez-Eixarch, Institute for Food & Agricultural Research & Technology (IRTA), Tarragona, Spain
Thursday 17 January 2013, 1300-1400
Since salinity is the main limiting factor to yield in Ebro Delta rice fields, water management in these fields mainly consists of continuous flooding during the whole crop cycle (paddy rice) to limit salt ingress to the rhizosphere. However, flooding conditions may affect rice vegetative growth by impairing bud and root system development, thereby decreasing yield. Consequently, intermittent irrigation (alternate wetting and drying - AWD) was considered a promising water management technology because of the combined effects of promoting early vegetative growth by enabling more oxygen diffusion to the rhizosphere, and preventing high levels of salinity by keeping an intermittent layer of water over the soil surface. Moreover, using AWD may reduce overall water consumption which is crucial in a Mediterranean environment.
A three-year (2007-2009) study was conducted in Ebro Delta rice field area (Northeast Spain) to assess the effect of agronomic factors such as plant density, nitrogen fertilization and water management on rice tillering and crop productivity. The objective was to test the hypothesis that AWD improves rice crop productivity by promoting early tillering. The results confirmed that 1) AWD combined with early nitrogen fertilization at tillering stage promotes earlier tillering and that 2) premature tillering tended to increase grain yield provided late tiller development is prevented.