Compaction and shading effects on surface cracking in a vertisol uri icon

abstract

  • The effects of soil compaction and shading on surface cracking were studied in miniplots on a Vertisol at ICRISAT Center. Two distinctly different types of cracking were observed: (1) Type 1, wide and deep cracks, associated with bigger intercrack structural units (ISUs); (2) Type 2, narrow and shallow cracks, associated with smaller ISUs. Although differences in the areal shrinkage on the soil surface were rather small across the treatments, compaction and shading resulted in Type-1 cracking, and uncompacted and unshaded treatments produced Type-2 cracking. The equivalent diameter of ISUs was increased approximately twice by shading and three times by compaction. These differences may be attributed to: (1) structural changes during compaction; (2) structural adjustments during drying. A qualitative model of crack initiation, which explains the observed effects, has been proposed.These results have important applications in soil management. Type-1 cracking may improve infiltration and internal drainage and effective storage of water in subsurface layers. But for efficient seedling establishment. Type-2 cracking is preferred. Field experiments to test these concepts are warranted

publication date

  • 1989
  • 1989