*3.2.2. Soil crusting*

**Figure 4.** The penetration resistance (a and b), crusting index (c), plant available water content (d), surface runoff (e)

The penetration resistance affecting crop yield is not a constant value and varies according to other soil properties. Indeed, it was reported that there was no penetration problem under 2000 KPa, but crop yields were affected over 2.00 MPa [26]. However, some researchers claim that the crop yield is affected by PR of >3.00 MPa [27–29]. Soil penetration resistance is a valuable indicator of the soil physical quality. A value of 2 MPa has been widely used as a

and soil loss (f) maps of the basin.

100 Land Degradation and Desertification - a Global Crisis

Crusting index is recognized as one of the major forms of soil degradation. In this study, CI was calculated using soil organic matter, clay, and silt contents. Soils with high CI values tend to have a higher tendency to form crust [39]. Soil organic matter content ranged from 0.41 to 4.33% for topsoil and from 0.14 to 2.32% in subsoil. Approximately 95% of the soils in the basin had low CI values (CI of <5), which indicates low tendency to form crust. The CIs of the basin soil results are shown in **Tables 4** and **5** and **Figure 4c**.
