Institutional Repository
Technical University of Crete
EN  |  EL

Search

Browse

My Space

Simulation of greenhouse tomato cultivation with the SALTMED model: scenarios of irrigation quality and climate change

Apostolakis Antonios

Full record


URI: http://purl.tuc.gr/dl/dias/B8641645-CEB2-4468-8217-2D20F2F9ACC9
Year 2017
Type of Item Master Thesis
License
Details
Appears in Collections

Summary

Soil salinity is a major soil degradation threat that hinders agricultural production, soil fertility and water resources quality. In arid coastal environments, such as those of the Mediterranean region, the deteriorated quality of irrigation water due to sea water intrusion and the applied intensive agricultural practices promote soil salinization and compromise the sustainability of agricultural production. On top of these, protected horticultural crops have to cope with increasing irrigation needs, while Climate Change may further augment these needs due to increases in crop evapotranspiration. In this study, the SALTMED model is calibrated using soil moisture, soil salinity and crop yield measurements collected from on a small-scale Solanum lycopersicum (tomato) greenhouse pot experiment that simulates the semi-arid conditions in the RECARE Project Case Study in Greece (Timpaki, Crete). The use of local planting soil with initial Electrical Conductivity (ECse) of 18 dS m-1 and local cultivation practices aims to replicate prevailing conditions at the Case Study. Ten plants are drip irrigated with two irrigation quality treatments: low salinity (LS, ECw = 1.1 dS m-1) and moderately salinity (MS, ECw = 3.5 dS m-1) irrigation water, resulting to high and excessively high final ECse, respectively. Based on these approaches, the calibrated SALTMED model is employed to predict soil salinity and crop’s irrigation needs, water uptake and final yield under different irrigation ECw (ranged from 1.1 to 7.0 dS m-1) and climatic conditions. Increased ECw exerts a profound reduction on modelled water uptake with a changing loss rate (ca. 17% for ECw < 3.25 dS m-1 and 30% for ECw > 3.25 dS m-1) and crop yield (ca. -15% for a unit increase in ECw). The MS treatment leads to a reduced crop yield by 28% and a curtailed water uptake by 29% comparted with the LS treatment. These effects are attributed to the increased osmotic stress. Impact on final soil ECse is also determined by the interaction between the salt inputs and the fraction of water available for leaching. Climate Change increases modelled crop evapotranspiration by 5-17% and water requirements by 4-14% regardless of the irrigation quality. Under the LS treatment, simulated crop yield is not affected by Climate Change and the water uptake is projected to increase by 4-13% balancing the increased water needs. In contrast, the combined effect of poor irrigation quality (MS treatment) and Climate Change leads to reduction in crop yield by 31-35%, while water uptake is reduced by 23-28% compared to the LS treatment. Climate Change provokes an increase upon modelled soil ECse and its impact is greater during the last warmer months of the cultivation. LS treatment concludes to a greater increase of simulated ECse under Climate Change when compared with MS treatment, because of the increased simulated water uptake that reduces water leaching fraction.

Available Files

Services

Statistics