scholarly journals Short and Long-Term Effect of Land Use and Management on Soil Organic Carbon Stock in Semi-Desert Areas of North Africa-Tunisia

Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1267
Author(s):  
Fatma Baraket ◽  
Manuel González-Rosado ◽  
Nadhem Brahim ◽  
Núria Roca ◽  
Hadda Ben Mbarek ◽  
...  

Soil organic carbon (SOC) plays an important role in the global C cycle, as well as in the maintenance and improvement of the soil quality. Over time, special attention has been paid to it in the study of the SOC reserves worldwide; however, reduced attention has been given to assessing the spatial patterns of SOC stock (SOCS) in semi-desert ecosystems. In this line, there are no conclusive studies in drylands of Africa affected by aeolian processes (semi-desert conditions) mainly due to the complexity of sample collection, and this is especially significant in some soil types such as Arenosols (AR) and Calcisols (CL). This study evaluated the spatial variability of SOC and SOCS in AR and CL with woody crops in relation to land use and management (old plantations > 100 years: centenary olive grove; new plantations < 12 years: young olive grove, almond, and pistachio) in semi-desert conditions. For this purpose, 16 soil profiles (for 0–40 and 40–100 cm depth) were selected and studied in an experimental area of Menzel Chaker-Sfax in southeastern Tunisia (North Africa). The main results indicated that the SOCS on average was higher in Old Cultivated AR (OC-AR) with 41.16 Mg ha−1 compared to Newly Cultivated AR (NC-AR) with 25.13 Mg ha−1. However, the SOCS decreased after a long period of cultivation in CL from 43.00 Mg ha−1 (Newly Cultivated CL: NC-CL) to 32.19 Mg ha−1 (Old Cultivated CL: OC-CL). This indicates that in the long term, CL has more capacity to store SOC than AR, and that in the short term, AR is more sensitive to land management than CL.

Soil Research ◽  
2014 ◽  
Vol 52 (7) ◽  
pp. 717 ◽  
Author(s):  
Yong Li ◽  
Hanqing Yu ◽  
Adrian Chappell ◽  
Na Zhou ◽  
Roger Funk

Soil organic carbon (SOC) redistribution by soil erosion is fundamental to the C cycle and is a key component of global soil C accounting. Widespread conversion of cropland to forest and grassland and the adoption of conservation agriculture (minimum-till and no-till practices) worldwide and particularly in China since 2000, may have reduced wind erosion and increased SOC storage and ‘avoided’ CO2 emission. However, few SOC sequestration studies have separated changes in SOC stock caused by changes in land-use and management activity from net SOC redistribution due to reduced SOC erosion and SOC dust accumulation, particularly from individual or short-term (months) wind erosion events. We used measurements of SOC and the short-lived natural radionuclide beryllium-7 (7Be, half-life 53.3 days) to estimate net SOC redistribution for changes in several land-use and management practices in Fengning County in North China. Compared with conventional tillage (CT), conservation grassland (CG) and minimum tillage (CL) showed enhanced SOC stocks (0–245 mm depth) of ~0.8 ± 0.03 and 2.0 ± 0.06 t C ha–1 year–1 as a consequence of their land-use conversion for 5 and 3 years, respectively. However, SOC erosion on CG (0.46 ± 0.04 t C ha–1 year–1) and CL (0.52 ± 0.04 t C ha–1 year–1) plots was 54% and 47%, respectively, less than on CT (0.99 ± 0.11 t C ha–1 year–1). Net C sequestration (0–245 mm), considering SOC redistribution for CG (0.27 ± 0.12 t C ha–1 year–1; 5 years) and CL (1.53 ± 0.13 t C ha–1 year–1; 3 years), revealed an overestimate of 196% and 31% without considering SOC redistribution (CG, 0.8 ± 0.03 t C ha–1 year–1; CL, 2.0 ± 0.06 t C ha–1 year–1), respectively, relative to CT. Reduced SOC erosion and/or SOC dust accumulation by vegetation–crop cover must be included when considering SOC sequestration induced by changes in land use and management.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.


2014 ◽  
Vol 14 (2) ◽  
pp. 103-108 ◽  
Author(s):  
S Bhandari ◽  
S Bam

The study was carried out in Chovar village of Kritipur Municipality, Kathmandu to compare the soil organic carbon (SOC) of three main land use types namely forest, agricultural and barren land and to show how land use and management are among the most important determinants of SOC stock. Stratified random sampling method was used for collecting soil samples. Walkley and Black method was applied for measuring SOC. Land use and soil depth both affected SOC stock significantly. Forest soil had higher SOC stock (98 t ha-1) as compared to agricultural land with 36.6 t ha-1 and barren land with 83.6 t ha-1. Similarly, the SOC in terms of CO22-1, 79.27 to 22.02 CO2-e ha-1 and 121.11 to 80.74 CO2-1 for 0- 20 cm to 40-60 cm soil depth, respectively. Bulk density (BD) was found less in forest soil compared to other lands at all depths, which showed negative correlation with SOC. The study showed a dire need to increase current soil C stocks which can be achieved through improvements in land use and management practices, particularly through conservation and restoration of degraded forests and soils.   DOI: http://dx.doi.org/10.3126/njst.v14i2.10422   Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 103-108


Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 141
Author(s):  
Alwyn Williams ◽  
Ryan Farquharson ◽  
David Lawrence ◽  
Jeff Baldock ◽  
Mike Bell

Land-use type is known to affect levels of soil organic carbon (SOC). However, the degree to which SOC is affected by land-use type over the short—(<10-years) and long—(≥10-years) term remains relatively uncertain. Moreover, there is limited data on the distribution of SOC across particulate (POC), humus (HOC) and resistant (ROC) fractions, and the responses of these fractions to land-use. Using mid-infrared spectroscopy (MIR) coupled with partial least squares regression (PLSR) algorithms generated from the Australian Soil Carbon Research Program (SCaRP), soil organic carbon (TOC, POC, HOC and ROC) was estimated across 280 paired samples across Australia’s Northern Grains Regions. Our analysis covered five land-use types: remnant native vegetation, long-term pasture (≥10-years), short-term pasture (<10-years), short-term cropping (<10-years) and long-term cropping (≥10-years). All land-use types except long-term pasture generated significant declines across all SOC fractions compared with native vegetation. Long-term cropping resulted in the greatest declines, with an average decrease of 6.25 g TOC/kg soil relative to native vegetation. Long-term cropping also reduced POC (−0.71 g/kg) and HOC (−3.19 g/kg) below that of short-term cropping. In addition, the ROC fraction responded to land-use type, with native vegetation and long-term pasture maintaining greater ROC compared with other land-use types. The results demonstrate substantial reductions across all SOC fractions with long-term cropping. The ability of long-term pastures to maintain levels of SOC similar to that of native vegetation indicates the importance of limiting soil disturbance and maintaining more continuous living plant cover within cropping systems.


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