H. Majdi, M. Karimian- Eghbal, H. R. Karimzadeh, A. Jalalian,
Volume 10, Issue 3 (fall 2006)
Abstract
Stabilizng sand dunes has been one of the main challenges in the arid regions. So far, different kinds of mulches have been used extensively for sand dune stabilization. This study was carried out to determine the optimum composition, concentration and thickness of clay mulch for sand dune stabilization. For this purpose two soil samples from clay flats of a playa with different amount of salinity from Ardestan area were used to make clay mulches. A sand dune sample was selected as bed for applying the mulch. To select the right ingredient and treatments, clay samples were mixed with sand and different amount of water, and sprayed on sand dune bed. In addition, wheat straw was added to some mixture to test its effect on stability of the mulch. Treatments with lowest crack and highest penetration of mulch in sand bed were selected for the experiment in this study. Mulch treatments contained (1): 250g sand dune + 250g clay + 25g straw (2) 250g clay + 25g straw (3) 250g sand + 250g clay (4) 250g clay (5) 125g sand + 125g clay and (6) 125g clay. All treatments were mixed with 500ml water. The experimental design was a CRD with a 6(mulch) * 2(thickness)* 2 EC factorial method with 3 replications. The results showed that clay mulch were resistant to wind erosion, but erosion took place when they had been bombarded with sandblast. The mulches with straw showed the highest resistance to erosion as compared to other treatments. With increasing the number of mulch layers, resistant to erosion also increased. The added stability of mulch was due to the increase in mulch thickness and also increases in clay and silt content. The overall result of this study shows that the mulch with two layers and higher mixture of clay and sands was the best treatment for the stabilization of sand dunes.
K. Nosrati, M. Majdi,
Volume 21, Issue 4 (Winter 2018)
Abstract
The soil pollution especially in urban soils is projected to increase drastically and its effects on chemical cycles are yet to be known. Approaches to measure air and water quality are well established, but urban soil quality assessment has received little attention. Soil quality assessment can help as a way to better understand the pollution increase outcomes in urban environments and to establish approaches and integrated soil quality assessment protocols in urban planning and landscape management. Considering lack of information in urban soil quality of Iran, the objective of this study was to assess soil quality under urban land use effect using minimum data set in western part of Tehran. In view of this, 56 soil samples were collected in three land use types of agricultural, parks and urban landscapes, and vacant urban lots and 12 physicochemical properties were measured. The results of analysis of variance (one-way ANOVA) showed that under influence of the land use types, organic carbon, total nitrogen, lime, bulk density and sodium have significant differences. The factor analysis was used to select minimum data set and the results showed that two factors with eigenvalues more than one, explaining more than 68% of total variance, have the most loading factors on organic carbon and sodium. Finally, soil quality indicator (SQI) was determined and compared in different land use types. The results showed that SQI has significant difference in urban land use types and the least soil quality is related to vacant urban lots.
