Morocco - Tensift

Operational Implementation Plans

The team has installed an observatory running since 2002 ( which is collecting basically meteorological data (rainfall, wind speed, T, Rg) for about ten permanent stations, and additionally some fluxes experiments measuring especially ET using eddy correlation, soil moisture). These flux measurements are done each year on some annual crops (wheat) or during several years on permanent land cover (trees, rainfed wheat).

Chichaoua’17 experiment

For the 2016-2017 season, and experiment comparing drip and traditional gravity irrigated wheat was installed including a lysimeter to monitor soil percolation. The objective is to evaluate the water budget and associated (irrigation, evaporation, transpiration, drainage) fluxes of two 1.5 ha drip-irrigated wheat fields, one field being irrigated according to the water needs estimated by the FAO method and the other field being irrigated exactly the same way except during controlled stress periods when irrigation is cut. Station-based instrumentation includes eddy covariance towers, radiometers in various spectral bands, lysimeters and ground heat flux, sap flow and soil moisture/potential/temperature sensors. The response of wheat to various levels of water availability is also characterized by manual measurements of carbon and water fluxes using a canopy chamber, and at leaf scale the water potential, stomatal conductance, chlorophyll content and fluorescence. 

Thanks to this dataset, we want to analyze  the link between Photochemical Reflectance Index (PRI) and the Light Use Efficiency (LUE) at canopy scale on wheat grown under different water regimes (irrigated or rainfed). The Photochemical Reflectance Index (PRI) is based on the short term reversible xanthophylls pigment changes accompanying plant stress and therefore of the associated photosynthetic activities. Strong relationships between PRI and LUE were shown at leaf and canopy scales and over a wide range of species (Garbulsky et al., 2011). But very few previous works have explored the potential link with plant water status. In this context, we investigate the daily and seasonal dynamics of PRI; linking its variations to meteorological factors (global radiation and sun angle effects, soil water content, relative air humidity …) and plant processes. We explore relationships between PRI and sapflow measurements (i.e. transpiration rate) to evaluate the potential of this index to detect and monitor a moderate plant water stress.

The experiment on winter wheat for the 2016-2017 season, including eddy correlation (right) and lysimeter (left).

The Sidi Rahal monitoring station was set up in a rainfed wheat field in December 2013. Due to an unusual lack of precipitation late 2015, the winter wheat crop had not been planted during the 2015-2016 season. As a result, the crop field remained in bare soil conditions from January to September 2016. This unique “bare soil” data set is being used to test new radar-based retrieval approaches of surface soil moisture and new formulations of soil evaporation.

Tahanaout experiment

A 1.4 km scintillometer transect has been running for one year on traditional agriculture areas (including mainly olive trees and annual crops (wheat mainly) in the Haouz plain at the outlet of the high Atlas mountains. To complement this set-up and especially test aggregation of fluxes over heterogeneous surfaces, two eddy correlation towers are currently being installed under this transect.

©2015 Joint Experiment for Crop Assessment and Monitoring