Using 137Cs and 210Pbex measurements to explore the effectiveness of soil conservation measures in semi-arid lands: a case study in the Kouhin region of Iran

2018 ◽  
Vol 19 (4) ◽  
pp. 2103-2113 ◽  
Author(s):  
Maral Khodadadi ◽  
Lionel Mabit ◽  
Mohammad Zaman ◽  
Paolo Porto ◽  
Manouchehr Gorji
2020 ◽  
Author(s):  
Lilian Niacsu ◽  
Ion Ionita ◽  
Claudia Samoila ◽  
Georgel Grigoras ◽  
Ana-Maria Belebea-Apostu

<p>Land degradation by soil erosion, gullying, landslides and reservoir sedimentation is a major environmental threat in the Barlad Plateau of Romania. This paper reviews both land degradation and the development of soil conservation measures in a representative 32,908 ha catchment. Previous studies focused on larger regional areas and provided insufficient detailed information about land degradation and land improvements. Results estimated the mean value of soil loses at 22.7 t ha-1 y-1 based mostly on the USLE. Gully erosion is very limited in extent (covering 3% of the catchment area), but has considerable impacts in terms of sediment production and triggering or reactivating landslides. The 1:5,000 scale landslide distribution map shows that 56% of Racova Catchment is covered by landslides, in any shape or age. Most of them are shallow seated and inactive landslides. Traditional agriculture in the Barlad Plateau focused on ‘up-and-down slope’ farming on small plots. Soil conservation measures were actively undertaken over a 20-year period (1970-1989). However, more recent legislation (No. 18/1991 Agricultural Real Estate Act) includes two provisions that discourage maintaining and extending soil conservation practises. Hence, the former contour farming system has been abandoned in favour of the traditional, degradational farming methods. The mean annual sedimentation rate in reservoirs is moderate at 2.7 cm y-1 in the upper Racova Catchment and almost double that rate in Puscasi Reservoir at the catchment outlet. Consequently, land degradation remains a serious problem in the study area and effective soil conservation is urgently needed.</p>


2015 ◽  
Vol 7 (1) ◽  
pp. 115-145 ◽  
Author(s):  
Y. Mohawesh ◽  
A. Taimeh ◽  
F. Ziadat

Abstract. Land degradation resulting from improper land use and management is a major cause of declined productivity in the arid environment. The objectives of this study were to examine the effects of a sequence of land use changes, soil conservation measures, and the time since their implementation on the degradation of selected soil properties. The climate for the selected 105 km2 watershed varies from semi-arid sub-tropical to Mediterranean sub-humid. Land use changes were detected using aerial photographs acquired in 1953, 1978, and 2008. A total of 218 samples were collected from 40 sites in three different rainfall zones to represent different land use changes and different lengths of time since the construction of stone walls. Analyses of variance were used to test the differences between the sequences of land use changes (interchangeable sequences of forest, orchards, field crops, and range), the time since the implementation of soil conservation measures, and rainfall on the thickness of the A-horizon, soil organic carbon content, and texture. Soil organic carbon reacts actively with different combinations and sequences of land use changes. The time since stone walls were constructed showed significant impacts on soil organic carbon and the thickness of the surface horizon. The effects of changing the land use and whether the changes were associated with the construction of stone walls, varied according to the annual rainfall. The results help in understanding the effects of land use changes on land degradation processes and carbon sequestration potential and in formulating sound soil conservation plans.


2019 ◽  
Vol 24 (5) ◽  
pp. 529-553 ◽  
Author(s):  
Chandan Singha

AbstractThis study evaluates the effects of vegetative soil conservation practices (afforestation and/or bamboo planting) on farm profit and its components, revenue and variable cost. Since farmers self-select themselves as adopters of conservation measures, there could be a problem of selection bias in evaluating their soil conservation practices. We address the selection bias by using propensity score matching. We also check if there exists spatial spillover in adoption of vegetative conservation measures and how it affects matching. We use primary survey data from the Darjeeling district of the Eastern Himalayan region for the year 2013. Our results suggest strong spatial correlation. We find that the propensity score estimated from the spatial model provides better matches than the non-spatial model. While the results show that vegetative soil conservation can lead to significant gains in revenue, it also increases costs so that no significant gains in profit accrue to farmers.


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