Jina Eskef *⁽¹⁾_, Jihad Ibrahim ⁽¹⁾, Rabei Zaineh⁽²⁾  and Nabil Habib⁽¹⁾

(1)- Dept. of soil and water, Faculty of Agriculture, Tishreen University. Lattakia, Syria.

(2)- Lattakia center, General commission for scientific Agriculture research (GCSAR), Damascus, Syria

(3) Dept. of Field crop, Faculty of Agriculture, Tishreen University. Lattakia, Syria.

(*Corrsponding author: Jina Eskef. E-mail: Jina.Eskef@gmail.com).

Received: 18/9/2019          Accepted: 14/7 /2020

Abstract:

The research was conducted in Lattakia ( at Dabba research station) in clay-loam soil,  it had designed as Randomized Complete Block Design ( 6 treatments and 3 replicates for each treatment) the soil was exposed to three levels of pressure (0, 187.5, 307.4 ) Kpa respectively, then the compressed soil was tilled up to 20cm in depth homogeneously and the subsurface soil remained compressed  in different levels, a mechanical disassembly for compressed subsurface soil was conducted at shrinkage limit (SL) via mechanical disassembly in addition to control treatment without disassembly. The study showed a significant increase in bulk density by increasing the pressure and the highest value was at 307.4 Kpa, the disassembly led to decrease it significantly by 0.11 and 0.17 g/cm³ at the pressure levels 187.5 and 307.4 Kpa respectively. That confirm the important role of disassembly by moving the layers of compressed subsurface soil. Also, the mechanical disassembly led to a significant increase in the bulk of macro porosity by 4.17% at 187.5 Kpa and 6.44% at 307.4 Kpa compared with no disassembly treatments. As well as the pores which their diameter more than 10µm increased by 3.78 and 6.7% at the pressure levels of 187.5 and 307.4 Kpa respectively. The soil compacting led to decrease in the size of pores that contains the available water capacity by 3.69% and the mechanical disassembly increased these pores by 2.91% at 307.4 Kpa. Also, the soil compacting and increasing its density led to decrease the values of saturated conductivity coefficient with increasing the pressure and the value of pressure was 1.17m/day at 187.5 Kpa and decreased to 0.091m/day at 307.4Kpa exceeding the threshold limit value, the disassembly led to a significant increase in its value and the increment value was 0.69 and 1.43m/day at the pressures 187.5 and 307.4 Kpa respectively.

 Keywords: Compression, Subsurface Soil, Mechanical disassembly, physical properties.

Full paper in Arabic: PDF