Carbon sequestration and soil restoration potential of grazing lands under exclosure management in a semi‐arid environment of northern Ethiopia

Abstract

Exclosures are used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, this study assessed the impact of grazing exclosure on carbon sequestration and soil nutrients under 5 and 10 years of grazing exclosures and freely grazed areas in Tigray, northern Ethiopia. Carbon stocks and soil nutrients increased with increasing grazing exclusion. However, open grazing lands and 5 years of grazing exclosure did not differ in above‐ and belowground carbon stocks. Moreover, 10 years of grazing exclosure had a higher (p < 0.01) grass, herb and litter carbon stocks compared to 5 years exclosure and open grazing lands. The total carbon stock was higher for 10 years exclosure (75.65 t C ha‐1) than the 5 years exclosure (55.06 t C ha‐1) and in open grazing areas (51.98 t C ha‐1). Grazing lands closed for 10 years had a higher SOC, organic matter, total N, available P, and exchangeable K + and Na + compared to 5 year's exclosure and open grazing lands. Therefore, establishment of grazing exclosures had a positive effect in restoring degraded grazing lands, thus improving carbon sequestration potentials and soil nutrients.

Peer Review #1 of "Effects of afforestation with Pinus sylvestris var. mongolica plantations combined with enclosure management on soil microbial community (v0.1)"

“…However, previous study from Inner Mongolia grasslands finding that soil pH increased and became more neutral with the increase of enclosure time (Ma et al, 2016). What's more, we further found that PSME could increase soil nutrients significantly than PSM, including soil total C, total N, total P and available N contents (P < 0.05), which was agreement with the studies about grassland from Xiong et al (2016) and Gebregergs et al (2019). The increase in total C and total N concentrations might be mainly ascribed to the undergrowth vegetation recovery, accumulation of litter and increase in soil nutrient return in PSME (Table 1), and changes in the "quality" and "quantity" of litter lay an important role in affecting the soil nutrient (Rajr et al, 2006).…”

“…The increase in total C and total N concentrations might be mainly ascribed to the undergrowth vegetation recovery, accumulation of litter and increase in soil nutrient return in PSME (Table 1), and changes in the "quality" and "quantity" of litter lay an important role in affecting the soil nutrient (Rajr et al, 2006). Identically, results of the impact of grazers on birch forest demonstrated that aboveground carbon stocks were higher in the long-term absence of sheep than in the continual presence of high sheep densities (Gebregergs et al, 2019).…”

“…Manuscript to be reviewed Gebregergs et al, 2019). For example, several forest enclosure trials have reported that forest enclosure could increase the diversity and density of saplings and seedlings, quantity of natural herb, understory vegetation, as well as the cover of litters (Cabin et al, 2000;Miller & Wells, 2003;Dodd & Power, 2007), and decrease soil compaction and erosion (Spooner et al, 2002;Michels et al, 2012), subsequently increasing the soil organic C and N derived from litter decomposition and root exudation (Bai et al, 2012;Wu et al, 2014), facilitating forest establishment (Speed et al, 2014).…”

Non-utilization Is Not the Best Way to Manage Lowland Meadows in Hulun Buir

“…Furthermore, the correlations between plant community diversity and soil physicochemical properties differed among the four sites (Supplementary Tables 3A,B). This finding is similar to the results of many studies in which the correlations between plant communities and soil physicochemical properties were not uniform across different grassland types and utilization patterns (Herrero-Jáuregui and Oesterheld, 2017;Fayiah et al, 2019;Gebregergs et al, 2019).…”

Ecosystem restoration in fire-managed savanna woodlands: Effects on biodiversity, local livelihoods and fire intensity

“…Some respondents pointed out that the grass inside our exclosures looked like it used to look like earlier, and that this is the preferred pasture status. Long-term studies of community exclosures in Northern Ethiopia show an increase in field layer biomass and species diversity (Mekuria et al 2018;Gebregergs et al 2019). We found a small difference in species composition, likely caused by the differential palatability of the species; e.g.…”