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 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.

scholarly journals Food Limitation During Breeding in a Heterogeneous Landscape

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Martin Granbom ◽  
Henrik G. Smith
Keyword(s):  
Spatial Variation ◽  
Breeding Success ◽  
Statistical Power ◽  
Food Limitation ◽  
Agricultural Landscapes ◽  
Food Supplementation ◽  
Breeding Period ◽  
Foraging Habitat ◽  
Growth And Survival ◽  
Supplemental Food

Abstract Breeding success in birds may be determined by the availability of food that parents can provide to growing nestlings. A standard method for testing the occurrence of food limitation is to provide supplemental food during different parts of the breeding period. If there is spatial variation in the strength of food limitation, the effect of such an experiment should also vary spatially. We investigated whether the strength of food limitation during nestling rearing in the European Starling (Sturnus vulgaris) was related to the management intensity of agricultural landscapes. We fed birds mealworms during the nestling period in landscapes with high or low local availability of pasture, the preferred foraging habitat. Both habitat and food supplementation affected growth and survival of nestlings; the effects of the food-supplementation experiment were generally stronger than those of habitat. Mortality mainly struck the last-hatched chick. Both habitat and food supplementation positively affected nestling growth, measured as nestling tarsus length. In addition, food supplementation positively affected feather growth and asymptotic mass. Contrary to expectation, no interactions existed between effects of habitat and food supplementation, which suggests that breeding success was limited by food availability in both landscapes. Potential reasons for this lack of effect are parental compensation and low statistical power. Also, breeding densities were higher in landscapes with more pastures, possibly equalizing the per-capita availability of food. Thus, our results demonstrate that reproductive success was limited by availability of food when local availability of preferred foraging habitat was either low or high, but fail to demonstrate spatial variation in the strength of food limitation. Escasez de Alimentos durante el Período Reproductivo en un Paisaje Heterogéneo

scholarly journals Soil Quality Assessment Strategies for Evaluating Soil Degradation in Northern Ethiopia

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Gebreyesus Brhane Tesfahunegn
Keyword(s):  
Soil Quality ◽  
Expert Opinion ◽  
Soil Degradation ◽  
Management Practices ◽  
Principal Component ◽  
Eragrostis Tef ◽  
Northern Ethiopia ◽  
Scoring Functions ◽  
Soil Quality Index ◽  
Triticum Vulgare

Soil quality (SQ) degradation continues to challenge sustainable development throughout the world. One reason is that degradation indicators such as soil quality index (SQI) are neither well documented nor used to evaluate current land use and soil management systems (LUSMS). The objective was to assess and identify an effective SQ indicator dataset from among 25 soil measurements, appropriate scoring functions for each indicator and an efficient SQ indexing method to evaluate soil degradation across the LUSMS in the Mai-Negus catchment of northern Ethiopia. Eight LUSMS selected for soil sampling and analysis included (i) natural forest (LS1), (ii) plantation of protected area, (iii) grazed land, (iv) teff (Eragrostis tef)-faba bean (Vicia faba) rotation, (v) teff-wheat (Triticum vulgare)/barley (Hordeum vulgare) rotation, (vi) teff monocropping, (vii) maize (Zea mays) monocropping, and (viii) uncultivated marginal land (LS8). Four principal components explained almost 88% of the variability among the LUSMS. LS1 had the highest mean SQI (0.931) using the scoring functions and principal component analysis (PCA) dataset selection, while the lowest SQI (0.458) was measured for LS8. Mean SQI values for LS1 and LS8 using expert opinion dataset selection method were 0.874 and 0.406, respectively. Finally, a sensitivity analysis (S) used to compare PCA and expert opinion dataset selection procedures for various scoring functions ranged from 1.70 for unscreened-SQI to 2.63 for PCA-SQI. Therefore, this study concludes that a PCA-based SQI would be the best way to distinguish among LUSMS since it appears more sensitive to disturbances and management practices and could thus help prevent further SQ degradation.

To the issue of water treatment by hydrocyclone on the systems of the combined irrigation

2020 ◽  
Vol 0 (2) ◽  
pp. 21-25
Author(s):  
Nikolay Dubenok ◽  
Andrey Novikov ◽  
Sergei Borodychev ◽  
Maria Lamskova
Keyword(s):  
Water Treatment ◽  
Organic Compounds ◽  
Irrigation Water ◽  
Irrigation System ◽  
Petroleum Products ◽  
Cylindrical Part ◽  
Agricultural Landscapes ◽  
Treatment Unit ◽  
Drain Pipe ◽  
Irrigation Network

At the stage of water treatment for irrigation systems, the efficiency capture coarse and fine mechanical impurities, as well as oil products and organic compounds affects the reliability of the equipment of the irrigation network and the safety of energy exchange processes in irrigated agricultural landscapes. The violation of work irrigation system can cause disruptions in irrigation schedules of agricultural crops, crop shortages, degradation phenomena on the soil and ecological tension. For the combined irrigation system, a water treatment unit has been developed, representing a hydrocyclone apparatus with a pipe filter in the case. For the capacity of 250 m3/h the main geometrical dimensions of hydrocyclone have been calculated. To organize the capture petroleum products and organic compounds, it has been proposed a modernization of a hydrocyclone unit, consisting in dividing the cylindrical part of the apparatus into two section. The first is section is for input irrigation water, the second one is for additional drainage of clarified irrigation water after sorption purification by the filter, placed on the disk and installed coaxially with the drain pipe and the pipe filter.

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