Improvement of vegetation condition and soils fertility in the arid rangelands of Morocco by restoration and rehabilitation techniques

L’amélioration de l’état de la végétation et de la fertilité des sols est une préoccupation majeure pour une réhabilitation réussie dans les parcours dégradés. Cette étude examine l’impact de la mise en repos, de la technique de conservation de l’eau et du sol (CES) et de la plantation fourragère sur le recouvrement de la végétation, la phytomasse, la valeur énergétique de la phytomasse (UF.ha-1), le pH, la matière organique (MO), le phosphore assimilable (P), le calcaire total (CaT), le potassium échangeable (K), le sodium échangeable (Na) et la conductivité électrique (CE) dans cinq sites différents. Les résultats montrent que ces techniques permettent de restaurer les parcours steppiques en induisant une dynamique positive de la végétation et du sol. Ainsi, la mise en repos, la technique de CES et la plantation d’Atriplex nummularia ont entraîné une accumulation de la matière organique dans les sols et ont amélioré le recouvrement, la phytomasse et la valeur énergétique de la végétation avec des valeurs allant jusqu’à 85 %, 2,84 t.ha-1 et 931 UF.ha-1 respectivement. Par contre, le site en pâturage libre est marqué par une phytomasse inférieure à 0,31 t.ha-1, correspondant à une valeur énergétique inférieure à 46 UF.ha-1, et par un recouvrement végétal inférieur à 6 %. Ce site est marqué aussi par des taux du sodium échangeable (Na) et de conductivité électrique (CE) élevés avec des valeurs moyennes de 463,65 mg.kg-1 et 4,66 mS.cm-1 respectivement.Improving vegetation condition and soil fertility is a major concern for successful rehabilitation in degraded rangelands. This study examines the impact of fencing, water and soil conservation technique (CES) and fodder shrub plantations (Atriplex nummularia) on vegetation cover, phytomass, energy value of phytomass (UF.ha-1), pH, organic matter (MO), available phosphorus (P), total limestone (CaT), exchangeable potassium (K), exchangeable sodium (Na) and electrical conductivity (EC) in five different sites. Results show that these techniques can restore the rangeland steppe by inducing a positive dynamics of vegetation and soil. Hence, fencing, CES and Atriplex nummularia trained an accumulation of organic matter in soils and they improved cover, phytomass and energy value of vegetation until 85 %, 2.84 t.ha-1 and 931 UF.ha-1 respectively. On the other hand, the free grazing site is marked by a phytomass less than 0.31 t.ha-1 corresponding to an energy value less than 46 UF.ha-1 and a global cover less than 6 %. This site is also marked by high levels of exchangeable sodium (Na) and electrical conductivity (CE) with average values of 463.65 mg.kg-1 and 4,66 mS.cm-1 respectively

The application of proximal visible and near-infrared spectroscopy to estimate soil organic matter on the Triffa Plain of Morocco

Soil organic matter (SOM) is a fundamental soil constituent. The estimation of this parameter in the laboratory using the classical method is complex time-consuming and requires the use of chemical reagents. The objectives of this study were to assess the accuracy of two laboratory measurement setups of the VIS-NIR spectroscopy in estimating SOM content and determine the important spectral bands in the SOM estimation model. A total of 115 soil samples were collected from the non-root zone (0-20 cm) of soil in the study area of the Triffa Plain and then analysed for SOM in the laboratory by the Walkley-Black method. The reflectance spectra of soil samples were measured by two protocols, Contact Probe (CP) and Pistol Grip (PG)) of the ASD spectroradiometer (350-2500 nm) in the laboratory. Partial least squares regression (PLSR) was used to develop the prediction models. The results of coefficient of determination (R-2) and the root mean square error (RMSE) showed that the pistol grip offers reasonable accuracy with an R-2 = 0.93 and RMSE = 0.13 compared to the contact probe protocol with an R-2 = 0.85 and RMSE = 0.19. The near-Infrared range were more accurate than those in the visible range for predicting SOM using the both setups (CP and PG). The significant wavelengths contributing to the prediction of SOM for (PG) setup were at: 424, 597, 1432, 1484, 1830,1920, 2200, 2357 and 2430 nm, while were at 433, 587, 1380, 1431, 1929, 2200 and 2345 nm for (CP) setup

Developping an optimal soil and water quality monitoring network for the Triffa irrigated perimeter (Eastern of Morocco)

In Morocco, the irrigated areas play a key role as real centers for agricultural and rural development, both at local and regional level. Thus, the irrigated agriculture contributes to about 45% on average of the agricultural value added. However, it is noted that the water and soil of different irrigated areas are excessively exploited and threatened by different degradation problems. In this study, we aim to design an advanced methodology allowing to monitor soil and water quality in the irrigated perimeter of Triffa. The study area is the most fertile and productive agricultural region of north-east Morocco.The surface area of the plain rises to 61 000 ha of which 36 060 ha are irrigated. The climate is warm semi-arid. The mean annual rainfall in 28 years is 331 mm. The mean annual temperature is 17.2 ◦C. Recognized by the quality of its clementine, the Triffa plain experienced during the last decade a large and rapid expansion of irrigated areas mainly citrus through improved irrigation. Recent studies have shown that in this region, soil and water resources are under pressure due to salinization and groundwater nitrate pollution. The degradation of soil and water resources is largely caused by the increased use of agrochemicals, such as nitrogen fertilizers and pesticides, and the lack of control of irrigation and drainage of the plots. The protection and the preservation of these resources are top priority necessities, particularly in arid zones. We first aim to identify robust indicators of soil and groundwater degradation. These indicators should be able to measure the different functions and services provided by the soil and water system. Subsequently, we will design a spatial network allowing to evaluate the state of the soil and water resource. We will use geostatistical and GIS tools to optimize the monitoring network. This study is undertaken within the framework of a CUD-PIC project, aiming to develop tools for the management of water and soils resources in the irrigated perimeter of Morocco

Amélioration de l’état de la végétation et de la fertilité des sols des parcours arides du Maroc par les techniques de restauration et de réhabilitation

Improvement of vegetation condition and soils fertility in the arid rangelands of Morocco by restoration and rehabilitation techniques. Improving vegetation condition and soil fertility is a major concern for successful rehabilitation in degraded rangelands. This study examines the impact of fencing, water and soil conservation technique (CES) and fodder shrub plantations (Atriplex nummularia) on vegetation cover, phytomass, energy value of phytomass (UF. ha-1), pH, organic matter (MO), available phosphorus (P), total limestone (CaT), exchangeable potassium (K), exchangeable sodium (Na) and electrical conductivity (EC) in five different sites. Results show that these techniques can restore the rangeland steppe by inducing a positive dynamics of vegetation and soil. Hence, fencing, CES and Atriplex nummularia trained an accumulation of organic matter in soils and they improved cover, phytomass and energy value of vegetation until 85 %, 2.84 t. ha-1 and 931 UF. ha-1 respectively. On the other hand, the free grazing site is marked by a phytomass less than 0.31 t. ha-1 corresponding to an energy value less than 46 UF. ha-1 and a global cover less than 6 %. This site is also marked by high levels of exchangeable sodium (Na) and electrical conductivity (CE) with average values of 463.65 mg. kg-1 and 4,66 mS.cm-1 respectively.L’amélioration de l’état de la végétation et de la fertilité des sols est une préoccupation majeure pour une réhabilitation réussie dans les parcours dégradés. Cette étude examine l’impact de la mise en repos, de la technique de conservation de l’eau et du sol (CES) et de la plantation fourragère sur le recouvrement de la végétation, la phytomasse, la valeur énergétique de la phytomasse (UF. ha-1), le pH, la matière organique (MO), le phosphore assimilable (P), le calcaire total (CaT), le potassium échangeable (K), le sodium échangeable (Na) et la conductivité électrique (CE) dans cinq sites différents. Les résultats montrent que ces techniques permettent de restaurer les parcours steppiques en induisant une dynamique positive de la végétation et du sol. Ainsi, la mise en repos, la technique de CES et la plantation d’Atriplex nummularia ont entraîné une accumulation de la matière organique dans les sols et ont amélioré le recouvrement, la phytomasse et la valeur énergétique de la végétation avec des valeurs allant jusqu’à 85 %, 2,84 t. ha-1 et 931 UF. ha-1 respectivement. Par contre, le site en pâturage libre est marqué par une phytomasse inférieure à 0,31 t. ha-1, correspondant à une valeur énergétique inférieure à 46 UF. ha-1, et par un recouvrement végétal inférieur à 6 %. Ce site est marqué aussi par des taux du sodium échangeable (Na) et de conductivité électrique (CE) élevés avec des valeurs moyennes de 463,65 mg. kg-1 et 4,66 mS.cm-1 respectivement.Hachmi Azeddine, Andich Karim, Ezzahra El Alaoui-Faris Fatima, Mahyou Hamid. Amélioration de l’état de la végétation et de la fertilité des sols des parcours arides du Maroc par les techniques de restauration et de réhabilitation. In: Revue d'Écologie (La Terre et La Vie), tome 73, n°4, 2018. pp. 401-413

Potential of VIS-NIR spectroscopy to characterize and discriminate topsoils of different soil types in the Triffa plain (Morocco)

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