A new ecohydrological model based on Richard equation

Cortis C;MONTALDO, NICOLA

2013-01-01

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Abstract

The evapotranspiration is a key term in the hydrological water balance of the Mediterranean ecosystems because can reach the same values of the annual precipitation [2], [36]. In this work a typical heterogeneous ecosystem is considered , it includes 3 cover types: the bare soil and two different Plant Functional Types (PFTs, e.g., grass and woody vegetation) because the presence of the two PFTs in the same system plays a crucial role in the development of water use strategies. In Mediterranean ecosystems the competition of the different vegetation types for the water use is very important, especially during the water stress periods (spring and summer) that are crucial for the management and the planning of the water resources. In the present work a new ecohydrological model based on Richard equation has been developed to simulate numerically the vertical soil moisture variability and the vertical distribution of plant roots. The root distribution of the two PFTs considered, is an important term to quantify the root water uptake and the different strategies developed by the species in drought conditions. Two vegetation dynamic models (VDMs) coupled with the Richard model simulate the physiological trials of the plants in terms of distribution and evolution of the radical systems in the soil of the two PFTs, using a macroscopic approach. The model has been applied to the experimental site of Orroli in the Mid-West of Sardinia (Italy). Results show a good performance of the model in terms of soil moisture and evapotranspiration. The two species show a different behavior in terms of root distribution during the drought periods (summer).