Management strategies for reducing soil degradation through modeling in a GIS environment in northern Ethiopia catchment

2012 ◽  
Vol 92 (3) ◽  
pp. 255-272 ◽  
Author(s):  
Gebreyesus Brhane Tesfahunegn ◽  
Paul L. G. Vlek ◽  
Lulseged Tamene
Keyword(s):  
Soil Degradation ◽  
Management Strategies ◽  
Northern Ethiopia ◽  
Gis Environment

scholarly journals Assessing Sediment-Nutrient Export Rate and Soil Degradation in Mai-Negus Catchment, Northern Ethiopia

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Gebreyesus Brhane Tesfahunegn ◽  
Paul L. G. Vlek
Keyword(s):  
Soil Degradation ◽  
Soil Samples ◽  
Northern Ethiopia ◽  
Nutrient Export ◽  
Replacement Cost ◽  
Soil Calcium ◽  
Standard Procedures ◽  
Central Ridge ◽  
Nutrient Replacement ◽  
Potassium Magnesium

Even though soil degradation challenges sustainable development, the use of degradation indicators such as nutrient export (NE) and nutrient replacement cost is not well documented at landform level. This study is aimed to investigate the extent of soil degradation, NE rates, and their replacement cost across landforms in the Mai-Negus catchment, northern Ethiopia. Different erosion-status sites (aggrading, stable, and eroded) in the landforms were identified, and soil samples were randomly collected and analysed. Nutrient export, replacement cost, and soil degradation were calculated following standard procedures. This study showed that soil degradation in the eroded sites ranged from 30 to 80% compared to the corresponding stable site soils, but the highest was recorded in the mountainous and central ridge landforms. Average NE of 95, 68, 9.1, 3.2, 2.5, and 0.07 kg ha−1 y−1 for soil calcium, carbon, nitrogen, potassium, magnesium, and phosphorus, respectively, was found from the landforms. Significantly strong relationships between NE and sediment yield in the landforms were observed. Annual nutrient replacement costs varied among the landforms though the highest was in the reservoir (€9204 in May 2010). This study thus suggests that while introducing antierosion measures, priority should be given to erosion sources to the reservoir such as mountainous and central ridge landforms.

GIS–Multicriteria Evaluation with Ordered Weighted Averaging (OWA): Case Study of Developing Watershed Management Strategies

2003 ◽  
Vol 35 (10) ◽  
pp. 1769-1784 ◽  
Author(s):  
Jacek Malczewski ◽  
Terry Chapman ◽  
Cindy Flegel ◽  
Dan Walters ◽  
Dan Shrubsole ◽  
...  
Keyword(s):  
Management Strategies ◽  
Evaluation Criteria ◽  
Weighted Averaging ◽  
Optimal Order ◽  
Combination Rules ◽  
Ordered Weighted Averaging ◽  
Multicriteria Evaluation ◽  
Evaluation Procedures ◽  
Creek Watershed ◽  
Gis Environment

This paper focuses on the parameterized-ordered weighted averaging (OWA) method. OWA is a family of multicriteria evaluation (or combination) rules. The proposed approach uses a parameter that serves as a mechanism for guiding multicriteria evaluation procedures. The parameter is incorporated into a method for obtaining the optimal order weights and for developing a transformation function. The function provides us with a consistent way of modifying the criterion values so that the multicriteria combination procedures can be guided by specifying a single parameter. The parameterized-OWA method has been implemented in a GIS environment as a GIS–OWA module and it has been tested in a real-world situation for developing management strategies in the Cedar Creek watershed in Ontario, Canada. Given a set of evaluation criteria, the problem is to evaluate areas in the watershed for rehabilitation and enhancement projects. Using the GIS–OWA method, a number of alternative strategies for rehabilitation and enhancement projects have been generated and evaluated.

Construction and analysis of Hydrogeological Landscape units using Self-Organising Maps

Soil Research ◽  
2016 ◽  
Vol 54 (3) ◽  
pp. 328 ◽  
Author(s):  
M. J. Cracknell ◽  
A. L. Cowood
Keyword(s):  
Land Management ◽  
Learning Algorithm ◽  
Management Strategies ◽  
Boolean Logic ◽  
Management Decision ◽  
Spatial Distributions ◽  
Geographic Space ◽  
Landscape Characteristics ◽  
Management Actions ◽  
Gis Environment

The Hydrogeological Landscape (HGL) framework divides geographic space into regions with similar landscape characteristics. HGL regions or units are used to facilitate appropriate management actions tailored to individual HGL units for specific applications such as dryland salinity and climate-change hazard assessment. HGL units are typically constructed by integrating data including geology, regolith, soils, rainfall, vegetation and landscape morphology, and manually defining boundaries in a GIS environment. In this study, we automatically construct spatially contiguous regions from standard HGL data using Self-Organising Maps (SOM), an unsupervised statistical learning algorithm. We compare the resulting SOM-HGL units with manually interpreted HGL units in terms of their spatial distributions and attribute characteristics. Our results show that multiple SOM-HGL units successfully emulate the spatial distributions of individual HGL units. SOM-HGL units are shown to define subregions of larger HGL units, indicating subtle variations in attribute characteristics and representing landscape complexities not mapped during manual interpretation. We also show that SOM-HGL units with similar attributes can be selected using Boolean logic. Selected SOM-HGL units form regions that closely conform to multiple HGL units not necessarily connected in geographic space. These SOM-HGL units can be used to establish generalised land management strategies for areas with common physical characteristics. The use of SOM for the construction of HGL units reduces the subjectivity with which these units are defined and will be especially useful over large and/or inaccessible regions, where conducting field-based validation is either logistically or economically impractical. The methodology presented here has the potential to contribute significantly to land-management decision-support systems based on the HGL framework.

scholarly journals Analysis of soil degradation in the Czech Republic: GIS approach

2010 ◽  
Vol 5 (No. 3) ◽  
pp. 108-112 ◽  
Author(s):  
B. Šarapatka ◽  
M. Bednář ◽  
P. Novák
Keyword(s):  
Czech Republic ◽  
Soil Compaction ◽  
Soil Degradation ◽  
Specific Weight ◽  
Chemical Degradation ◽  
The Czech Republic ◽  
Spatial Analyst ◽  
Gis Environment ◽  
The Individual ◽  
Physical Degradation

In our work, we have evaluated the available data on the individual types of soil damage, which has been processed in the Czech Republic in recent decades. The individual types of degradation (water erosion, wind erosion, soil compaction, extreme soils (clay soils), loss of organic matter, acidification, dryness impact, and intoxication) were classified in one of three groups: physical degradation, desertification and chemical degradation. Each type of degradation was assigned a specific weight reflecting the importance of this kind of soil degradation. The maps of individual areas of degradation were processed by overlay and assigning weighting techniques in ArcView Spatial Analyst GIS environment to create the final maps for each class of the degradation threat. The same technique was used to create the final map showing the most troubled areas in the Czech Republic, threatened by soil damage.

Challenges for weed management in African rice systems in a changing climate

2011 ◽  
Vol 149 (4) ◽  
pp. 427-435 ◽  
Author(s):  
J. RODENBURG ◽  
H. MEINKE ◽  
D. E. JOHNSON
Keyword(s):  
Weed Management ◽  
Soil Degradation ◽  
Production Systems ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Global Changes ◽  
Negative Consequences ◽  
Mechanical Control ◽  
Parasitic Weeds ◽  
Management Approaches

SUMMARYGlobal changes including increases in temperature, atmospheric greenhouse gases, soil degradation and competition for land and water resources, will have multiple impacts on rice production systems in Africa. These changes will affect weed communities, and management approaches must be adapted to take this into account. Higher temperatures and limited water availability will generally advantage C4over C3plants (e.g. rice). Conversely, elevated carbon dioxide (CO2) levels will improve the competitiveness of rice relative to C4weeds, which comprise many of the problem weeds of rice. Increased atmospheric CO2levels may also improve tolerance of rice against parasitic weeds, while prevalence of parasitic species may be amplified by soil degradation and more frequent droughts or floods. Elevated CO2levels tend to promote growth below-ground relative to above-ground, particularly in perennial (C3) species. This may render mechanical control of weeds within a cropping season less effective or even counterproductive. Increased CO2levels, rainfall and temperature may also reduce the effectiveness of chemical control, while the implementation of adaptation technologies, such as water-saving irrigation regimes, will have negative consequences for rice–weed competition. Rain-fed production systems are prevalent throughout Africa and these are likely to be most vulnerable to direct effects of climate change (e.g. higher temperatures and changes in rainfall patterns). Effective weed management strategies in these environments could encompass off-season tillage, the use of well-adapted cultivars (i.e. those with drought and heat tolerance, high weed competitiveness and parasitic weed resistance or tolerance) and rotations, intercropping or short, off-season fallows with weed-suppressive legumes including those that suppress parasitic weeds. In irrigated, non-flooded rice systems, weeds are expected to become more serious. Specifically, perennial rhizomatous C3weeds and species adapted to hydromorphic conditions are expected to increase in prevalence. By implementing an integrated weed management strategy primarily targeted at weed prevention, dependency on flood water, herbicides and mechanical control can be lessened. Off-season deep tillage, stale seed bed techniques, use of clean seeds and irrigation water, competitive cultivars, timely transplanting at optimum spacing and judicious fertilizer timings are suitable candidate components for such a strategy. Integrated, novel approaches must be developed to assist farmers in coping with the challenges of weed control in the future.

scholarly journals Spatial variation in biodiversity, soil degradation and productivity in agricultural landscapes in the highlands of Tigray, northern Ethiopia

Food Security ◽  
2009 ◽  
Vol 1 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Kiros M. Hadgu ◽  
Walter A. H. Rossing ◽  
Lammert Kooistra ◽  
Ariena H. C. van Bruggen
Keyword(s):  
Spatial Variation ◽  
Soil Degradation ◽  
Agricultural Landscapes ◽  
Northern Ethiopia

scholarly journals Significant soil degradation is associated with intensive vegetable cropping in subtropical area: A case study in southwest China

2021 ◽  
Author(s):  
Ming Lu ◽  
David S. Powlson ◽  
Yi Liang ◽  
Zhi Yao ◽  
Dave R. Chadwick ◽  
...  
Keyword(s):  
Soil Degradation ◽  
Southwest China ◽  
Crop Residues ◽  
Management Strategies ◽  
Agricultural Practices ◽  
Nutrient Status ◽  
Fertilizer Application ◽  
Quality Parameters ◽  
Clear Trend ◽  
Soil C

Abstract. Within the context of sustainable development, soil degradation driven by land-use change is considered a serious global problem but conversion from growing cereals to vegetables is a change that has received little attention, especially in subtropical regions. Therefore, we compared the nutrient status and soil quality parameters (soil organic carbon [SOC], total nitrogen [TN], C / N ratio, pH, phosphorus [P], potassium [K], calcium [Ca], and magnesium [Mg]) between vegetable fields (VF) and land still used for paddy rice-oilseed rape rotation (PRF) that are typical of southwest China. In the VF, fertilizer application were often several times higher than the crop needs or recommended by the local extension service, thus, the crop use efficiency of N, P, K, Ca, Mg were only 26 %, 8 %, 56 %, 23 % and 28 %, respectively; SOC, C stock, TN, N stock decreased significantly caused by low organic inputs from crop residues and high tillage frequency, and soil C/N ratio decreased slightly; available P (AP) in topsoil increased by 1.92 mg kg−1 for every 100 kg ha−1 of surplus P, and the critical levels of AP and CaCl2-soluble P for P leaching were 104 and 0.80 mg P kg−1. Besides, there was a clear trend of soil acidification in the VF. However, increasing concentrations of soil Ca and Mg significantly alleviated topsoil acidification, with the effect increasing over time. Given our findings, we discuss the potential benefits of conservation agricultural practices, integrated soil-crop system management strategies and agricultural technology services for recovering the degraded soil and improving the vegetable productivity in the VF.

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