چکیده:
Wind erosion is a significant problem on 20 million ha of Iran, especially in central plains and coastal areas. Wind erosion samplers, meteorological equipments and measurement procedure have been developed over the last two centuries to measure the particles moving across the field in modes of creep, saltation and suspension. In recent research as the first technical measurement in Iran, wind erosion was measured with these advanced procedures. Field data was collected from a small (1.9 ha), square, fallow field with nonerodible boundaries. Wind erosion measurement equipment containing 14 clusters with samplers at 0.05, 0.10, 0.25, and 0.50 and 1.0m above the soil
surface and a 4× surface creep sampler (0 to 0.02m height by 0.005m wide) was arranged in a circular pattern. The sampling cluster consisted of an array of five samplers each attached to a pivoting wind vane and each mounted at a different height on a central pole. This permitted field erosion data collection regardless of the wind direction and provided a range of field lengths with a minimum number of sampler locations. A combination equation of power and
exponential functions expressed the variation of transition material to a height of 2m. An exponential model described the horizontal distribution of transported soil in the field. Twelve single events were recorded and analyzed between May 2006 and May 2007. Several inherent soil properties such as soil texture, organic matter and calcium carbonate content affect the erodibility of soil and change very slowly in research time. Other properties, such as
surface roughness and aggregate crust strength are temporal and change rapidly in response to climatic conditions. Total soil mass transported across the fallow field was measured at 220.93 kg/m per year and soil loss at 1.356 kg/m2 (13.56 ton/ha) per year.
خلاصه ماشینی:
Wind erosion samplers, meteorological equipments and measurement procedure have been developed over the last two centuries to measure the particles moving across the field in modes of creep, saltation and suspension.
Keywords: BSNE; Iran; Measurement; Near Surface Sampler; Wind Erosion 1.
Average wind soil loss due to wind erosion is about 19 ton/ha annually (Iran Forest and Rangeland Organization, 2000).
There are three variable scales for wind erosion measurement: (1) the point (1m2) scale for creep, (2) the field (<1 ha) scale for saltation and (3) the regional scale for suspension (Stroosnijder, 2005).
The vertical slot sampler designed by Bagnold (1973) was the first instrument used to collect eroded sand in the field, but did not adjust to changes in wind direction.
This permitted field erosion data collection regardless of the wind direction and provided a range of field lengths with a minimum number of sampler locations.
Soil transport was measured with BSNE clusters and near surface (creep) sampler's site as shown in Figure 4.
This research is the first accurate, reliable field wind erosion measuring in fallow lands.
Starting from a non-eroding upwind boundary, as the length of a field along the path of the eroding wind increases there is an increase in the quantity of material being transported between the soil surface to a height of 2 m.
Total soil mass transported across the fallow field in Yazd Ardakan plain was measured at 220.
Wind erosion: field measurement and analysis, Trans.
Efficiencies of sediment samplers for wind erosion measurement.