Mechanism of crust formation on a soil in central Iran

✍ Scribed by Mostafa K. Eghbal; Mohammad A. Hajabbasi; Hossein T. Golsefidi

• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 602 KB
• Volume: 180
• Category: Article
• ISSN: 0032-079X
• DOI: 10.1007/bf00015412

✦ Synopsis

Crust formation on soils around Isfahan reduces infiltration and seedling emergence in cultivated lands. Mechanism of crust formation on local soils was investigated under field condition. Soil and crust samples from a field under furrow irrigation were taken for physical, chemical and micromorphological analysis. Seedling emergence of sugar beets (Beta vulgaris) reduced by 50% due to crust forming after the first irrigation. Rise of water table, increase of exchangeable sodium percentage to 6.4, and higher silt content resulted in higher susceptibility of soil to crust formation. Crust forming inside furrows was thicker and usually consisted of 3 layers as compared to a thinner crust formed on beds with only 2 layers. Layers found in crusts of Lavark soil generally had less sand and more silt and fine clay compared to the overall Ap horizon. Silt and fine clay in the middle M2 layer of crust forming on furrows were increased from 51.6 and 5.6 to 59.8 and 21.1 percent respectively. Percolation of finer particles through and inside the pores created layers that were denser and less porous. Chemical dispersion of particles together with physical deterioration of surface structure by long period of mechanized agriculture in the area are probably the main reasons for crust formation.