Soil Organic Carbon and Nutrient Contents are not Influenced by Exclosures Established in Communal Grazing Land in Nile Basin, Northern Ethiopia

2016 ◽  
Vol 38 (3) ◽  
pp. 229 ◽  
Author(s):  
S. G. Bray ◽  
D. E. Allen ◽  
B. P. Harms ◽  
D. J. Reid ◽  
G. W. Fraser ◽  
...  

The grazing lands of northern Australia contain a substantial soil organic carbon (SOC) stock due to the large land area. Manipulating SOC stocks through grazing management has been presented as an option to offset national greenhouse gas emissions from agriculture and other industries. However, research into the response of SOC stocks to a range of management activities has variously shown positive, negative or negligible change. This uncertainty in predicting change in SOC stocks represents high project risk for government and industry in relation to SOC sequestration programs. In this paper, we seek to address the uncertainty in SOC stock prediction by assessing relationships between SOC stocks and grazing land condition indicators. We reviewed the literature to identify land condition indicators for analysis and tested relationships between identified land condition indicators and SOC stock using data from a paired-site sampling experiment (10 sites). We subsequently collated SOC stock datasets at two scales (quadrat and paddock) from across northern Australia (329 sites) to compare with the findings of the paired-site sampling experiment with the aim of identifying the land condition indicators that had the strongest relationship with SOC stock. The land condition indicators most closely correlated with SOC stocks across datasets and analysis scales were tree basal area, tree canopy cover, ground cover, pasture biomass and the density of perennial grass tussocks. In combination with soil type, these indicators accounted for up to 42% of the variation in the residuals after climate effects were removed. However, we found that responses often interacted with soil type, adding complexity and increasing the uncertainty associated with predicting SOC stock change at any particular location. We recommend that caution be exercised when considering SOC offset projects in northern Australian grazing lands due to the risk of incorrectly predicting changes in SOC stocks with change in land condition indicators and management activities for a particular paddock or property. Despite the uncertainty for generating SOC sequestration income, undertaking management activities to improve land condition is likely to have desirable complementary benefits such as improving productivity and profitability as well as reducing adverse environmental impact.


2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Kflay Gebrehiwot ◽  
Temesgen Desalegn ◽  
Zerihun Woldu ◽  
Sebsebe Demissew ◽  
Ermias Teferi

2021 ◽  
Author(s):  
Getahun Haile ◽  
Mulugeta Lemenih ◽  
Fisseha Itanna ◽  
Beyene Teklu ◽  
Getachew Agegnehu

Abstract Background Aim: Land use change causes a remarkable change in soil properties. The nature of change depends on multiple factors such as soil type, type and intensity of land use, climate, and the like. This study investigated the variation in soil physicochemical properties across five common land use practices i.e., enset system, farmland, and grazing-land (closed and open), and Eucalyptus woodlots practiced on originally same soil type and comparable topographic and climatic settings.Methods: A total of 105 disturbed and undisturbed soil samples [5 treatments (land use types) *7 replications (household)* 3 soil depth layers: 0–15cm, 15–30 cm, 30–45cm] were collected for selected soil chemical and physical analyses. Standard soil analytical procedures were followed in carrying out soil analysis. To meet the assumptions of normal distribution and homogeneity of variances, soil data on available phosphors were log-transformed before statistical analysis was undertaken and reported after back transformation. Two way analysis of variable were used to investigate the effects of land use and soil depth and their interaction on soil properties and when the analysis showed a significant difference (p <0.05) among land use and soil depth men separation were made using Turkey’s pairwise comparisons.Results: There were significant differences in physical and chemical properties of soil across land use and soil depth categories. Enset system had significantly higher pH, available phosphorus (P), exchangeable potassium (K+), soil organic carbon (SOC), and total nitrogen (TN) and their stocks than other land use types. Enset fields had higher SOC (78.4%) and soil TN (75%), and SOC and TN stocks of (66%) and (58%), respectively than cereal farmland. This study had also revealed a less expected finding of higher soil organic carbon and total nitrogen under Eucalyptus wood than farm land. Soil carbon and total nitrogen stocks showed a decreasing trend of enset system> closed grazing-land > eucalyptus woodlot > open grazing-land > farmland 0-45cm.Conclusion: Overall, some land use systems (e. g. enset agroforestry) improve the soil biophysical and chemical properties, while others such as cereal production degrade the soil. Hence appropriate land and soil management intervention should be promptly adapted to mitigating the continuous loss of nutrient from the dominantly practiced cereal farm land through maintaining crop residues, manure, crop rotation and scaling up agro-forestry system.


2021 ◽  
Author(s):  
Getnet Zeleke Tessera ◽  
Menberu Teshome Zeleke ◽  
Linger Ayele Mersha

Abstract Background: Land degradation is increasingly recognized as a serious, nationwide environmental concern in Ethiopia. The key concern is the iterative relationship between land degradation, climate change and agriculture, exacerbating one another via negative and positive feedback loops. Due to the need for an efficient response to land degradation in the country, different sustainable land management practices have been implemented since the late 1980s. In Ethiopia, most of the previous researches were conducted on analyzing the determinants of decisions to implement land management practices. The objective of this study was to analyze land degradation neutrality status using remote sensing data in the study area. Results: We have studied the land degradation neutrality conditions of North Wello Zone by using indicators data, namely land cover change, land productivity dynamics and soil organic carbon stock. The areas of settlement consistently expanded at the fifth speed (2010-2018) from 1995 to 2010. Between 1995 and 2010, forestland declined by 18 percent, while it indicated an increasing trend of 26.8 percent from 2010 to 2018. The wetlands declined by 21.98 percent from 1995 to 2010; whereas zero net degradation was observed from 2010 to 2020. In addition, between 1995 and 2010, cropland and grassland showed an increasing trend but decreasing trends were detected between 2010 and 2018. Land productivity potential assessment results indicate that 52.8 percent of the total area is stable and characterized by a less stressed land productivity status. Approximately 22.7 percent of the land showed an increase in land productivity status from 2001 to 2018. The results also indicated that 19.64 percent of the land shows an early sign of decline or actual land productivity decline. 3.5 percent of land also shows a decline in productivity. The soil organic carbon is comparatively abundant in the high and midland vegetation areas but very thin in lowland areas.Conclusion: Most of the highland and midland parts of the study areas are stable and increasing land productivity condition with high biomass and soil organic content. However, most lowland areas showed a decline land productivity condition.


2020 ◽  
Vol 12 (6) ◽  
pp. 2425
Author(s):  
Getu Abebe ◽  
Atsushi Tsunekawa ◽  
Nigussie Haregeweyn ◽  
Taniguchi Takeshi ◽  
Menale Wondie ◽  
...  

Soil organic carbon (SOC) and total nitrogen (TN) are key ecological indicators of soil quality in a given landscape. Their status, especially in drought-prone landscapes, is associated mainly with the land-use type and topographic position. This study aimed to clarify the effect of land use and topographic position on SOC and TN stocks to further clarify the ecological processes occurring in the landscape. To analyze the status of SOC and TN, we collected 352 composite soil samples from three depths in the uppermost soil (0–50 cm) in four major land-use types (bushland, cropland, grazing land, and plantation) and three topographic positions (upper, middle, and lower) at three sites: Dibatie (lowland), Aba Gerima (midland), and Guder (highland). Both SOC and TN stocks varied significantly across the land uses, topographic positions, and agro-ecosystems. SOC and TN stocks were significantly higher in bushland (166.22 Mg ha−1) and grazing lands (13.11 Mg ha−1) at Guder. The lowest SOC and TN stocks were observed in cropland (25.97 and 2.14 Mg ha−1) at Aba Gerima, which was mainly attributed to frequent and unmanaged plowing and extensive biomass removal. Compared to other land uses, plantations exhibited lower SOC and TN stocks due to poor undergrowth and overexploitation for charcoal and firewood production. Each of the three sites showed distinct characteristics in both stocks, as indicated by variations in the C/N ratios (11–13 at Guder, 10–21 at Aba Gerima, and 15–18 at Dibatie). Overall, land use was shown to be an important factor influencing the SOC and TN stocks, both within and across agro-ecosystems, whereas the effect of topographic position was more pronounced across agro-ecosystems than within them. Specifically, Aba Gerima had lower SOC and TN stocks due to prolonged cultivation and unsustainable human activities, thus revealing the need for immediate land management interventions, particularly targeting croplands. In a heterogeneous environment such as the Upper Blue Nile basin, proper understanding of the interactions between land use and topographic position and their effect on SOC and TN stock is needed to design proper soil management practices.


SOIL ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 239-251 ◽  
Author(s):  
Donia Jendoubi ◽  
Hanspeter Liniger ◽  
Chinwe Ifejika Speranza

Abstract. This study evaluates the impact of land use and topographic features (slope and aspect) on soil organic carbon (SOC) within the Wadi Beja watershed in north-western Tunisia. A soil spectral library was set up to assess the variation in the SOC for 1440 soil samples from four land use types (field crops, permanent crops, forest, and grazing land), three slope categories (flat, moderate, and steep) and two aspects (north- and south-facing). For field crops, only one factor – slope – significantly affected SOC, with SOC content in north-facing areas appearing to be higher in flat areas (0.75 %) than in hilly areas (0.51 %). However, in south-facing areas, SOC content was also higher in flat areas (0.74 %) than in hilly areas (0.50 %). For permanent crops, which were inter-planted with field crops, the slope significantly affected SOC content, which improved to 0.97 % in flat north-facing and 0.96 % in flat south-facing areas, scoring higher than hilly south- and north-facing areas (0.79 %). In the grazing land use system, both of the investigated factors – aspect and slope – significantly affected the SOC content, which was significantly higher in flat areas (north-facing: 0.84 %, south-facing: 0.77 %) than in hilly areas (north-facing: 0.61 %, south-facing: 0.56 %). For the forest, none of the factors had a significant effect on SOC content, which was higher in flat areas (north-facing: 1.15 %, south-facing: 1.14 %) than in steep areas (1.09 % in north-facing areas and 1.07 % in south-facing areas). This study highlights the ability of visible and near-infrared (VNIR) spectroscopy to quantify C in diverse soils collected over a large diverse geographic area in order to indicate that calibrations are feasible, and therefore, assessing the variation of SOC content under land use and topographic features (slope and aspect) will result in better sustainable land management planning.


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