Assessing soil and land health across two landscapes in eastern Rwanda to inform restoration activities

Abstract. Land degradation negatively impacts water, food, and nutrition security and is leading to increased competition for resources. While landscape restoration has the potential to restore ecosystem function, understanding the drivers of degradation is critical for prioritizing and tracking interventions. We sampled 300–1000 m2 plots using the Land Degradation Surveillance Framework across Nyagatare and Kayonza districts in Rwanda to assess key soil and land health indicators, including soil organic carbon (SOC), erosion prevalence, vegetation structure and infiltration capacity, and their interactions. SOC content decreased with increasing sand content across both sites and sampling depths and was lowest in croplands and grasslands compared to shrublands and woodlands. Stable carbon isotope values (δ13C) ranged from −15.35 ‰ to −21.34 ‰, indicating a wide range of historic and current plant communities with both C3 and C4 photosynthetic pathways. Field-saturated hydraulic conductivity (Kfs) was modeled, with a median of 76 mm h−1 in Kayonza and 62 mm h−1 in Nyagatare, respectively. Topsoil OC had a positive effect on Kfs, whereas pH, sand, and erosion had negative effects. Soil erosion was highest in plots classified as woodland and shrubland. Maps of soil erosion and SOC at 30 m resolution were produced with high accuracy and showed strong variability across the study landscapes. These data demonstrate the importance of assessing multiple biophysical properties in order to assess land degradation, including the spatial patterns of soil and land health indicators across the landscape. By understanding the dynamics of land degradation and interactions between biophysical indicators, we can better prioritize interventions that result in multiple benefits as well as assess the impacts of restoration options.

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Assessing biogeochemical and human-induced drivers of soil organic carbon to inform restoration activities in Rwanda

10.5194/soil-2020-67 ◽

2020 ◽

Author(s):

Leigh Ann Winowiecki ◽

Athanase Mukuralinda ◽

Aida Bargués-Tobella ◽

Providence Mujawamaria ◽

Elisée Bahati Ntawuhiganayo ◽

...

Keyword(s):

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Land Degradation ◽

Spatial Scales ◽

Stable Carbon Isotope ◽

Health Indicators ◽

Crop Productivity ◽

Land Restoration ◽

Wide Range

Abstract. Land restoration is of critical importance in Rwanda, where land degradation negatively impacts crop productivity, water, food and nutrition security. We implemented the Land Degradation Surveillance Framework in Kayonza and Nyagatare districts in eastern Rwanda to assess baseline status of key soil and land health indicators, including soil organic carbon (SOC) and soil erosion prevalence. We collected 300 topsoil (0–20 cm) and 281 subsoil (20–50 cm) samples from two 100 km2 sites. We coupled the soil health indicators with vegetation structure, tree density and tree diversity assessments. Mean topsoil organic carbon was low overall, 20.9 g kg−1 in Kayonza and 17.3 g kg−1 in Nyagatare. Stable carbon isotope values (d13CV-PDB ) ranged from −15.35 to −21.34 ‰ indicating a wide range of plant communities with both C3 and C4 photosynthetic pathways. Soil carbon content decreased with increasing sand content across both sites and at both sampling depths and was lowest in croplands compared to shrubland, woodland and grasslands. Field-saturated hydraulic conductivity (Kfs) was estimated based on infiltration measurements, with a median of 76 mm h−1 in Kayonza and 62 mm h−1 in Nyagatare, respectively. Topsoil OC had a positive effect on Kfs, whereas pH, sand and compaction had negative effects. Soil erosion was highest in plots classified as woodland and shrubland. Maps of soil erosion and SOC at 30-m resolution were produced with high accuracy and showed high variability across the region. These data and analysis demonstrate the importance of systematically monitoring multiple indicators at multiple spatial scales to assess drivers of degradation and their impact on soil organic carbon dynamics.

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Earth Observation for Accurate Mapping of Soil Functional Properties, Land Health and Soil Infiltrability in Rwanda

10.5194/egusphere-egu2020-19380 ◽

2020 ◽

Author(s):

Tor-Gunnar Vågen ◽

Leigh Ann Winowiecki ◽

Aida Bargues-Tobella

Keyword(s):

Hydraulic Conductivity ◽

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Properties ◽

Spatial Resolution ◽

Land Degradation ◽

Earth Observation ◽

Single Ring ◽

Land Health

Earth observation (EO) has a large potential for mapping of soil functional properties such as soil organic carbon, soil pH or acidity, soil fertility parameters and soil texture. Recent advances in the application of EO data in combination with systematic field data sampling, standardized soil data reference analysis and the use of soil spectroscopy have shown these approaches to be both robust and scalable. We present a case study from Rwanda where we apply EO data in combination with field and laboratory data collected using the Land Degradation Surveillance Framework (LDSF) to map functional soil properties, soil erosion prevalence and land cover at fine spatial resolution. Digital soil maps were produced at a spatial resolution of 30m with an accuracy of 85 to 90%, while soil erosion prevalence was mapped with an accuracy of 86% using Landsat satellite imagery and machine learning models.&#160;We also assess interactions between spatial assessments of soil organic carbon, soil erosion prevalence and land cover at a spatial resolution of 30m in order to identify land degradation hotspots and better target interventions to restore degraded land across four districts in Rwanda. We further explore the effects of soil erosion, root-depth restrictions and soil organic carbon content on saturated hydraulic conductivity in three LDSF sites in Nyagatare, Kayonza and Bugesera districts, respectively. Saturated hydraulic conductivity was modeled based on single-ring measurements of infiltration capacity using a modified Reynolds & Elrick steady-state single ring model for 48 LDSF plots per site. The results show significant spatial variation in infiltrability within sites.The results of the study show the importance of rigorous protocols for sampling and analyses of soil properties and indicators of land health across landscapes. By simultaneously assessing soil properties, indicators of land degradation and soil infiltrability we demonstrate the utility of these approaches in understanding drivers of land degradation across multiple spatial scales for targeting of options for land restoration and monitoring of the effectiveness of these interventions over time across multiple dimensions of land health.

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Predicting the Spatial Distribution and Severity of Soil Erosion in the Global Tropics using Satellite Remote Sensing

Remote Sensing ◽

10.3390/rs11151800 ◽

2019 ◽

Vol 11 (15) ◽

pp. 1800 ◽

Cited By ~ 1

Author(s):

Vågen ◽

Winowiecki

Keyword(s):

Soil Erosion ◽

Land Degradation ◽

Vegetation Cover ◽

Model Performance ◽

Health Indicators ◽

Terrestrial Ecosystems ◽

Observation Data ◽

Degraded Land ◽

Vulnerability To Climate Change ◽

Moderate Resolution Imaging Spectroradiometer

Soil erosion has long been recognized as a major process of land degradation globally, affecting millions of hectares of land in the tropics and resulting in losses in productivity and biodiversity, decreased resilience of both marine and terrestrial ecosystems, and increased vulnerability to climate change. This paper presents an assessment of the extent of soil erosion in the global tropics at a moderate spatial resolution (500 m) based on a combination of systematic field surveys using the Land Degradation Surveillance Framework (LDSF) methodology and Earth observation data from the Moderate Resolution Imaging Spectroradiometer (MODIS) platform. The highest erosion prevalence was observed in wooded grassland, bushland, and shrubland systems in semi-arid areas, while the lowest occurrence was observed in forests. Observed erosion decreased with increasing fractional vegetation cover, but with high rates of erosion even at 50–60% fractional cover. These findings indicate that methods to assess soil erosion need to be able to detect erosion under relatively dense vegetation cover. Model performance was good for prediction of erosion based on MODIS, with high accuracy (~89% for detection) and high overall precision (AUC = 0.97). The spatial predictions from this study will allow for better targeting of interventions to restore degraded land and are also important for assessing the dynamics of land health indicators such as soil organic carbon. Given the importance of soil erosion for land degradation and that the methodology gives robust results that can be rapidly replicated at scale, we would argue that soil erosion should be included as a key indicator in international conventions such as the United Nations Convention to Combat Desertification.

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Reversing land degradation through grasses: a systematic meta-analysis in the Indian tropics

Solid Earth ◽

10.5194/se-8-217-2017 ◽

2017 ◽

Vol 8 (1) ◽

pp. 217-233 ◽

Cited By ~ 5

Author(s):

Debashis Mandal ◽

Pankaj Srivastava ◽

Nishita Giri ◽

Rajesh Kaushal ◽

Artemi Cerda ◽

...

Keyword(s):

Soil Erosion ◽

Land Management ◽

Land Degradation ◽

Meta Analysis ◽

Pennisetum Purpureum ◽

Eastern Ghats ◽

Grass Species ◽

Western Himalayas ◽

Infiltration Capacity ◽

Degraded Pasture

Abstract. Although intensive agriculture is necessary to sustain the world's growing population, accelerated soil erosion contributes to a decrease in the environmental health of ecosystems at local, regional and global scales. Reversing the process of land degradation using vegetative measures is of utmost importance in such ecosystems. The present study critically analyzes the effect of grasses in reversing the process of land degradation using a systematic review. The collected information was segregated under three different land use and land management situations. Meta-analysis was applied to test the hypothesis that the use of grasses reduces runoff and soil erosion. The effect of grasses was deduced for grass strip and in combination with physical structures. Similarly, the effects of grasses were analyzed in degraded pasture lands. The overall result of the meta-analysis showed that infiltration capacity increased approximately 2-fold after planting grasses across the slopes in agricultural fields. Grazing land management through a cut-and-carry system increased conservation efficiencies by 42 and 63 % with respect to reduction in runoff and erosion, respectively. Considering the comprehensive performance index (CPI), it has been observed that hybrid Napier (Pennisetum purpureum) and sambuta (Saccharum munja) grass seem to posses the most desirable attributes as an effective grass barrier for the western Himalayas and Eastern Ghats, while natural grass (Dichanthium annulatum) and broom grass (Thysanolaena maxima) are found to be most promising grass species for the Konkan region of the Western Ghats and the northeastern Himalayan region, respectively. In addition to these benefits, it was also observed that soil carbon loss can be reduced by 83 % with the use of grasses. Overall, efficacy for erosion control of various grasses was more than 60 %; hence, their selection should be based on the production potential of these grasses under given edaphic and agro-ecological conditions. The present analysis also indicated that grass must be used as a vegetative strip to maintain soil quality in sloppy arable areas (8.5 Mha) of Indian hilly regions. Similarly, due attention should be paid for establishing grasses in 3 Mha of degraded pasture lands and 3.5 Mha of shifting cultivation areas in India to reverse the land degradation.

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Land degradation in savanna environments - assessments, dynamics and implications

10.5194/egusphere-egu21-15264 ◽

2021 ◽

Author(s):

Jussi Baade ◽

Jay J. Le Roux ◽

Theunis Morgenthal ◽

Hilma Sevelia Nghiyalwa

Keyword(s):

Remote Sensing ◽

Soil Erosion ◽

Land Cover ◽

Land Cover Change ◽

Land Degradation ◽

Field Work ◽

Spatial And Temporal Scales ◽

Wide Range ◽

Development Goals ◽

Decadal Climate

Land degradation is a human-induced process deteriorating ecosystem functioning and services including soil fertility or biological productivity and, usually, it is accompanied by a loss of biodiversity. Land degradation causes on-site and off-site damages like a profound change or removal of vegetation cover and soil erosion on one hand as well as flooding of receiving streams and siltation of reservoirs one the other hand. Thus, land degradation poses a threat to a number of Sustainable Development Goals (SDG) including foremost sustainable life on land and under water, the provision of clean water and eventually the eradication of poverty and hunger on Earth.Often, land cover change is a valid indicator of land degradation providing the opportunity to take advantage of the increasing geometrically and temporally high-resolution remote sensing capabilities to identify and monitor land degradation. However, especially in semi-arid regions like savanna environments, globally driven inter-annual and decadal climate variations cause as well profound land cover dynamics which might be mistaken for land degradation.Assessing and combating land degradation has already a long scientific, socio-economic and political history. Based on this, the aim of this session is to explore the wide range of methodological approaches to assess land degradation, its dynamics over all spatial and temporal scales as well as the implications for society and the interaction with the different spheres of the Earth including the anthroposphere, atmosphere, biosphere, hydrosphere and pedosphere. Contributions to this session can be based on field work, remote sensing approaches or modelling exercises, they can also focus on specific physical and socio-economic aspects of land degradation like land management, land cover change or soil erosion or discuss land degradation in a broader societal context. The aim of this contribution is to provide a concise overview of the thematic framework, current activities, research questions and advancements.

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Brief history and ways of further development of the department of hydraulic engineering and hydraulics FSBI «VNIIGiM named after A.N. Kostyakov»

Melioration and Water Management ◽

10.32962/0235-2524-2019-5-18-23 ◽

2020 ◽

pp. 18-23

Author(s):

Alexey Shcherbakov ◽

Valentin Zhezmer

Keyword(s):

Land Reclamation ◽

Water Source ◽

Water Sources ◽

Hydraulic Engineering ◽

Negative Effects ◽

Extensive Experience ◽

Safety Level ◽

Theoretical Substantiation ◽

Wide Range ◽

Construction Operation

Department of hydraulic engineering and hydraulics FGBNU «VNIIGiM them. A.N. Kostyakova «has a long history. For many years, the department’s staff has been such scientists and water engineers with extensive experience as M.A. Volynov, V.S. Verbitsky, S.S. Medvedev, N.V. Lebedev, B.C. Panfilov, T.G. Voynich-Syanozhentsky, V.A. Golubkova, G.V. Lyapin and others. The department solved a wide range of tasks, the main areas of research were the following: – theoretical and applied hydrodynamics and hydraulics, with reference to the open channel flows that affect the state and level of safety of the hydraulic structures; – integrated use and protection of water bodies – water sources and water sources of water resources used in land reclamation; – development of measures and technical solutions for the protection of objects from the negative effects of water; – theoretical substantiation of works to improve the safety level of the GTS (declaration); – development and implementation of digitalization methods for solving design, construction, operation and control of landreclamation facilities. Currently, promising areas of research is the development of a decision-making algorithm in the designation of measures to rationalize the provision of resources to water amelioration. The algorithm is developed on the basis of a detailed study, systematization and processing of data both on safety and on the efficiency of systems and structures, ensuring the delivery of irrigation water of the required quality and in sufficient quantity from a water source to the field.

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OCCURRENCE OF THE RISKS FOR DEVELOPMENT OF RESPIRATORY DISEASES IN CHILDREN EXPOSED TO THE CHEMICAL FACTORS OF THE EXPOSURE OF ALUMINA REFINERY- ASSOCIATED BUSINESS ACTIVITY

ЗДОРОВЬЕ НАСЕЛЕНИЯ И СРЕДА ОБИТАНИЯ - ЗНиСО / PUBLIC HEALTH AND LIFE ENVIRONMENT ◽

10.35627/2219-5238/2019-320-11-42-47 ◽

2019 ◽

pp. 42-47 ◽

Cited By ~ 1

Author(s):

M.A. Zemlianova ◽

I.V. Tikhonova

Keyword(s):

Respiratory Tract ◽

Respiratory Diseases ◽

Inflammatory Diseases ◽

Allergic Inflammation ◽

Respiratory Morbidity ◽

Upper Respiratory Tract ◽

Negative Effects ◽

Wide Range ◽

Chemical Factors ◽

Chronic Lymphoproliferative Diseases

Alumina refineries are among the leading sources of atmospheric air pollution with a wide range of pollutants hazardous to human respiratory organs. It is relevant to study and evaluate the occurrence of the risks for development of respiratory diseases in children living in the area affected by the emission components of an alumina refinery. We assessed air quality of the area under observation and comparison according to monitoring observations, risk of non-carcinogenic effects from the respiratory organs. The content of chemicals in the blood and urine adequate to risk factors was quantified. The structure of individual groups of respiratory diseases was analyzed. The causal relationships of violations of laboratory parameters with an increased content of chemicals in biological media were evaluated. It was found that an aerogenic exposure of chemical pollutants is formed on the territory with the production of metallurgical alumina. It determines the risk for development of respiratory diseases, exceeding an acceptable level up to 49.9 times. In the exposed children, the content of manganese, chromium, nickel, copper, xylenes, formaldehyde and aluminum, fluoride ion in the urine was increased to 4.2 times in relation to the indices in the comparison group. A high level of additional respiratory morbidity(1.8 times) was revealed. Chronic lymphoproliferative diseases of the nasopharynx and inflammatory diseases of the upper respiratory tract (up to 6.6 times more often), inflammatory diseases with a predominance of the mechanism of allergic inflammation ( up to 2.1 times more often)are more often detected in the framework of the respiratory diseases. Negative effects on the part of the respiratory system in the form of activation of antioxidant processes, the development of an inflammatory reaction, local, general and specific sensitization of the respiratory tract were established. It confirms the occurrence of the risks for the development of respiratory diseases in children in the exposure area of the chemical factors of alumina refinery-associated economic activity.

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Analyzing Regional Geographic Challenges: The Resilience of Chinese Vineyards to Land Degradation Using a Societal and Biophysical Approach

Land ◽

10.3390/land10020227 ◽

2021 ◽

Vol 10 (2) ◽

pp. 227

Author(s):

Yang Yu ◽

Jesús Rodrigo-Comino

Keyword(s):

Soil Erosion ◽

Land Degradation ◽

Environmental Concern ◽

Point Of View ◽

Irreversible Damage ◽

Erosion Rates ◽

Erosion Processes ◽

Lack Of Information ◽

Scientific Hypothesis ◽

Vineyard Soil

Land degradation, especially soil erosion, is a societal issue that affects vineyards worldwide, but there are no current investigations that inform specifically about soil erosion rates in Chinese vineyards. In this review, we analyze this problem and the need to avoid irreversible damage to soil and their use from a regional point of view. Information about soil erosion in vineyards has often failed to reach farmers, and we can affirm that to this time, soil erosion in Chinese vineyards has been more of a scientific hypothesis than an agronomic or environmental concern. Two hypotheses can be presented to justify this review: (i) there are no official and scientific investigations on vineyard soil erosion in China as the main topic, and it may be understood that stakeholders do not care about this or (ii) there is a significant lack of information and motivation among farmers, policymakers and wineries concerning the consequences of soil erosion. Therefore, this review proposes a plan to study vineyard soil erosion processes for the first time in China and develop a structured scientific proposal considering different techniques and strategies. To achieve these goals, we present a plan considering previous research on other viticultural regions. We hypothesize that the results of a project from a regional geographic point of view would provide the necessary scientific support to facilitate deriving guidelines for sustainable vineyard development in China. We concluded that after completing this review, we cannot affirm why vine plantations have not received the same attention as other crops or land uses.

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Responses to Ecopollutants and Pathogenization Risks of Saprotrophic Rhodococcus Species

Pathogens ◽

10.3390/pathogens10080974 ◽

2021 ◽

Vol 10 (8) ◽

pp. 974

Author(s):

Irina B. Ivshina ◽

Maria S. Kuyukina ◽

Anastasiia V. Krivoruchko ◽

Elena A. Tyumina

Keyword(s):

Survival Strategies ◽

Complex Life Cycle ◽

Anthropogenic Pressure ◽

Resting Cells ◽

Organic Substrates ◽

Negative Effects ◽

Anthropogenic Pollutants ◽

Rhodococcus Species ◽

Wide Range ◽

Rigid Cell Wall

Under conditions of increasing environmental pollution, true saprophytes are capable of changing their survival strategies and demonstrating certain pathogenicity factors. Actinobacteria of the genus Rhodococcus, typical soil and aquatic biotope inhabitants, are characterized by high ecological plasticity and a wide range of oxidized organic substrates, including hydrocarbons and their derivatives. Their cell adaptations, such as the ability of adhering and colonizing surfaces, a complex life cycle, formation of resting cells and capsule-like structures, diauxotrophy, and a rigid cell wall, developed against the negative effects of anthropogenic pollutants are discussed and the risks of possible pathogenization of free-living saprotrophic Rhodococcus species are proposed. Due to universal adaptation features, Rhodococcus species are among the candidates, if further anthropogenic pressure increases, to move into the group of potentially pathogenic organisms with “unprofessional” parasitism, and to join an expanding list of infectious agents as facultative or occasional parasites.

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Non-Standard Discrete RothC Models for Soil Carbon Dynamics

Axioms ◽

10.3390/axioms10020056 ◽

2021 ◽

Vol 10 (2) ◽

pp. 56

Author(s):

Fasma Diele ◽

Carmela Marangi ◽

Angela Martiradonna

Keyword(s):

Soil Carbon ◽

Land Degradation ◽

Biological Diversity ◽

Negative Effects ◽

Land Use Patterns ◽

Use Patterns ◽

Soil Carbon Content ◽

Rothc Model ◽

Key Indicators

Soil Organic Carbon (SOC) is one of the key indicators of land degradation. SOC positively affects soil functions with regard to habitats, biological diversity and soil fertility; therefore, a reduction in the SOC stock of soil results in degradation, and it may also have potential negative effects on soil-derived ecosystem services. Dynamical models, such as the Rothamsted Carbon (RothC) model, may predict the long-term behaviour of soil carbon content and may suggest optimal land use patterns suitable for the achievement of land degradation neutrality as measured in terms of the SOC indicator. In this paper, we compared continuous and discrete versions of the RothC model, especially to achieve long-term solutions. The original discrete formulation of the RothC model was then compared with a novel non-standard integrator that represents an alternative to the exponential Rosenbrock–Euler approach in the literature.

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