Organic Carbon and Alkalinity Increase in Topsoil After Rangeland Restoration Through Atriplex nummularia Plantation

Abstract

This research studied the impact of fodder shrub plantations (Atriplex nummularia Lindl.) on topsoil properties, with particular reference to organic carbon, nitrogen, and soluble salts, in the Marrakech region (central Morocco). The studied plantation interventions were carried out to rehabilitate degraded rangeland and to mitigate desertification. The field experiment was conducted by drawing seventeen 50-m-long transects designed according to the ecological patch-interpatch approach defined by the Landscape Function Analysis. The top soil (0-5 cm) was sampled in 134 microsites, covering the main patch and interpatch types in plantation and control plots. The following variables were determined: pH, carbonates, organic carbon, total nitrogen, electrical conductivity, and soluble ions (Na + , K + , Ca 2+ , Mg 2+ Cl À , NO 3 À , SO 4 2À and PO 4 3À ). Statistical analyses were carried out to analyse changes between sites and between patch types. Most of the studied properties were strongly affected by the spatial pattern defined by the plantation, particularly when the sites with higher biomass production were considered. Organic carbon increased by around 63% and 117% when the under canopy patches were compared, respectively, to the between-plants interpatches and to the control plots, a strong positive effect considering the aridity of the study area. On the other hand, a stronger increase was detected under canopy for most soluble salts and sodium adsorption rate. On average, the latter increased by 350% and up to 450% under the best developed plants, a stronger impact than observed in previous research, highlighting the very strong plant effect on the soil surface alkalinity.

Agricultural land abandonment in Mediterranean environment provides ecosystem services via soil carbon sequestration

“…This leads to reduction of soil erosion, increased infiltration rates, soil biological activity, and biomass and enhanced plant diversity. The acceleration of the biological and hydrological cycles after land abandonment results in recovery of soil carbon stocks as found by other studies when land was abandoned (Brevik and Lazari, 2014), forests were transformed into crops (Wasak and Drewnik, 2015), or when degraded rangelands were restored (Zucca et al, 2016). There is a positive interaction in the soil system after abandonment that favours the recovery of the biota (fauna and flora) followed by litter and organic matter, which finally improves soil quality and as a consequence the diversity and mass of the biota (Certini et al, 2015;Chen et al, 2016;Frouz, 2016).…”

Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems

“…On the other hand, contrasting effects were observed in sites located in arid central Morocco where halophyte shrubs (Atriplex nummularia Lindl.) were used to rehabilitate pastures (Zucca et al, 2015a). In this case, besides increasing soil organic matter and water infiltration, the plants have consistently increased the topsoil alkalinity (measured as SAR, or sodium adsorption ratio), showing that possible trade-offs have to be considered.…”

Land degradation monitoring using terrestrial ecosystem carbon sinks/sources and their response to climate change in China

“…The SOC data for China were derived from the 2nd National Soil Survey, which was conducted between 1979 and 1990. The SOC is not constant and changes (Liao et al, 2009;Zucca, Arrieta Garcia, Deroma, & Madrau, 2016), and it can be affected by environmental factors or human disturbance, such as land management (Smith et al, 2016;Willaarts, Oyonarte, Muñoz-Rojas, Ibáñez, & Aguilera, 2016). This old SOC data may thus not accurately describe the current SOC level in China, which can be demonstrated by the comparison of the Rh observations and modeled Rh values.…”