Background: Land degradation is a treat for natural resources in Tigray high lands of northern Ethiopia, where 30-50 percent of the soil productive capacity has been lost in the past 500 years. Restoration and management of degraded lands improve soil health through enhancing soil organic carbon (SOC) stock and microbial biomass carbon (MBC). The knowledge on SOC and MBC concentration and distribution is essential to refine soil management, thereby restoring the ecosystem. This paper quantified the effect of decades old community-based soil and water conservation (SWC) measures, mainly stone terraces, exclosure with and without stone terraces, and non-conserved communal grazing lands on the distribution of MBC and SOC stock.Methods: Soil sample collection was carried out using systematic sampling design. Transects parallel to each other and to the slope of the landscape were established. In each transect, three landscape positions (i.e., upper, middle, and foot slope) were formed. Composite soil samples were taken from four corners and center of 10 m × 10 m plot of each slope positions under the different SWC measures. Analysis of variance was used to determine the difference in SOC and MBC using SAS 9.2. Results:Total soil organic carbon concentration was significantly higher in exclosures as compared to terraces and non-conserved grazing lands. The highest mean value of SOC stock (29 Mg C ha ) was recorded in non-conserved communal grazing lands. Exclosures with terraces improved SOC stock by 64%, followed by exclosures without terraces by 37%, while terraces improved the SOC stock by 25% compared to non-conserved open communal grazing lands in the last 20 years. The upper (0-15 cm) soil depth had significantly (P < 0.05) higher (24 Mg C ha ). Microbial biomass carbon was the highest (640 mg kg −1 soil) in exclosures without terraces, followed by exclosures with terraces, (570 mg kg −1 soil), terraces (440 mg kg −1 soil), and non-conserved communal grazing lands (370 mg kg −1 soil). Conclusion:Exclosures supported with terraces improved and restored the SOC stock and microbial biomass carbon of degraded free grazing lands in the highlands.

Background: Land degradation is a major and widespread problem causing losses of ecosystem services in Ethiopia. Extensive utilization of the land resources for centuries resulted in severe land degradation in the Tigray region of northern Ethiopia. To reverse the problem, land restoration activities have been carried out for the past three decades. This study was initiated to determine the effect of community-based soil and water conservation interventions on soil glomalin, aggregate size distribution, water stable aggregates (WSA) and aggregate-associated organic carbon. Methods: Soil samples were collected from exclosures + terraces, exclosures alone, stone terraces and non-conserved grazing lands using systematic sampling based on slope positions. Results: Both easily extractable glomalin and total glomalin were significantly (p < 0.05) higher in exclosures compared to terraces and non-conserved grazing lands. The macroaggregate fraction of all SWC measures ranged 21.91-32.41%, where the lowest was in non-conserved grazing lands, while the highest was in exclosures with terraces. The micro-aggregate fraction ranged 19.9-26.66%, where the lowest was in exclosures, while the highest was in non-conserved grazing lands. The results also indicated that exclosures had significantly (p < 0.05) higher percent of WSA compared to terraces and non-conserved grazing lands. Mean weight diameter (MWD) was also significantly (p < 0.05) higher in exclosures. The WSA and MWD decreased in the order of exclosures with terraces > exclosures alone > terracess > non-conserved communal grazing lands. Comparison of aggregate-associated organic carbon (AAOC) showed relatively higher organic carbon in macroaggregates than in micro-aggregates. Besides, both macroand micro-aggregate-associated SOC was higher in exclosures than in terraces and non-conserved grazing lands. The AAOC of both macro-and micro-aggregates follows the order exclosures alone > exclosures + terraces > terraces > non-conserved communal grazing lands. Conclusion: Exclosures and terraces are important strategies for rehabilitation of degraded lands through improving glomalin content, aggregate structure and stability, and aggregate-associated organic carbon.

Background: Soil and water conservation measures (SWC) have a great practical significance to the restoration of arbuscular mycorrhiza (AMF). The objective of this study was to quantify the effect of decades long community-based soil and water conservation practices on arbuscular mycorrhiza fungi spore density, woody plant root colonization, and soil nutrients. Methods:The SWC measures considered were stone terraces, exclosures + stone terraces, exclosures alone, and adjacent non-conserved open communal grazing lands. Soil and root samples were collected from the rhizosphere of matured woody plant species using systematic sampling from 10 m × 10 m plot based on slope positions. Spores were isolated using wet sieving and decanting method, while AMF fungal root colonization was done using the gridline intersection method. Results:The study revealed that five major genera of AMF, including Glomus, Acaulospora, Gigaspora, Scutellospora, and Entrophospora were identified. Glomus was found to be the most abundant genera, which accounted for (52%) of the total spore density, followed by Acaulospora (18%). Besides, exclosures had the highest total spore density (60%) being followed by stone terraces (23%), whereas the lowest (17%) spore density was recorded in the open communal grazing lands. Total root colonization among the treatments ranged from 48.6% in the open communal grazing lands to 68.7% in the exclosure with terraces. Hyphal colonization was higher than arbuscular and vesicular colonization. The total colonization was in the order of exclosure with terraces > exclosure alone > terraces > non-conserved communal grazing lands. Conclusions:Rehabilitating the communal grazing lands with terraces and exclosure is an important approach for restoring AMF and regenerating the degraded lands.

Soil and water conservation (SWC) practices in the northern highlands of Ethiopia have important implications for land restoration and biodiversity recovery. The present study determined soil macroinvertebrate (SMI) abundance and diversity in response to spatial conditions i.e., generated by different conservation practices, soil depth, and temporal seasonality with the wet and dry season. The SWC practices considered were exclosure + terrace, exclosure alone, terraces, and non-conserved grazing lands. Each SWC measure was selected in three sites that were considered as replications due to low heterogeneity in terms of human and livestock disturbances and biophysical factors. Soil macroinvertebrates were collected using a monolith according to tropical soil biology and fertility (TSBF) method. The highest density (55%) of SMI was found in exclosures followed by terraces 26%. Non-conserved communal grazing lands account for only 19% of the total. Shannon diversity index was significantly (P < 0.05) higher (1.21) in the exclosures supported with terraces and the lowest (0.9) was observed in the non-conserved communal grazing lands. Diversity was also significantly (P < 0.05) higher (1.26) in wet than dry season (0.70). The highest (41%) Sorensen similarity index among SMI was found between exclosures with terraces and exclosures alone during the wet season. The lowest (20%) Sorensen similarity index was found between terraces alone and exclosures with terraces in dry season. Soil macroinvertebrate abundance was higher in upper (0-10 cm) than lower (10-20 and 20-30 cm) soil depth. Soil macroinvertebrate abundance was positively and strongly correlated with soil moisture (R 2 = 0.85) and soil organic carbon stock (R 2 = 0.95). However, it was negatively (R 2 = −0.71) correlated with bulk density. Generally, the abundance and diversity of SMI increased as exclosures and communal grazing lands are supported with terraces.

Background: Land-use change is one of the major factors affecting soil degradation. The pressures of the human population on land resources have increased land-use change with more negative effects on soil carbon storage and soil properties. The objective of this study was to assess the effect of land-use changes on soil organic carbon (SOC) stock and selected soil physicochemical properties in Gobu Sayyo, Western Ethiopia. Soil samples were collected from three adjacent land uses i.e., forest land, grazing land, and cultivated lands at 0-20cm and 20cm-40cm soil depths. A total of 36 composite soil samples were collected and the major soil properties and SOC storage of the area were analyzed and computed based on their standard procedures.Results: Soil organic carbon stock was significantly (p<0.05) higher (43.09-81.86 tone ha-1) in forest land and was significantly lower (38.08-43.09 tone ha-1) in cultivated land at the of depth of 0-20cm. SOC stock decreased with dept in all land uses. Changes in land use and soil depth affected the physical and chemical properties of soil. The physical soil property such as bulk density (BD) was higher (1.62 gcm-3) in the cultivated land whereas, the lowest (1.08 gcm-3) was recorded in the forest at 0-20cm depth. Comparatively the moisture content was higher (25.89%) under forest land at the depth of 20-40cm and was lower (11.22%) under cultivated lands. The chemical soil properties like exchangeable Ca2+, Mg2+, and K+ were higher in forest lands. Organic carbon, avP, TN, ex.Ca2+, ex.Mg2+, ex.K+, and CEC were lower under cultivated lands. pH increased with depth and was higher under forest land and lower under cultivated land. Soils of the study area are in general acidic to slightly acid with pH value ranging from 4-6-6.02. The pH, SOC, TN, av. Phosphorus and CEC were higher under forest land as compared to cultivated and grazing lands. Conclusion: It can be concluded that soil organic carbon stocks, the physical and chemical properties were affected by land-use change and depth. Therefore, reducing the intensity of cultivation, adopting integrated soil fertility management, and maintaining forest land must be practiced to save the soil of the area from degradation.