**4. Conclusion**

soil organic matter, sand, and bulk density were in the first group and CaCO3, silt, and

**Variables Factor 1 Factor 2 Factor 3 Factor 4 Factor 5 Factor 6 Factor 7** Mn, mg kg−1 0.86 0.05 0.11 −0.11 0.07 0.04 −0.19 pH −0.82 0.03 −020 −0.01 −0.22 −0.15 0.00 Fe, mg kg−1 0.82 0.17 −0.03 0.32 −0.09 −0.16 −0.08 Clay, % 0.07 0.93 −0.05 0.09 −0.03 0.00 −0.02 Sand, % −0.08 −0.93 0.09 0.05 −0.19 −0.12 −0.08

EC, mmhos cm−1 −0.44 0.57 0.04 0.49 0.25 −0.19 −0.10

HC, cm h−1 −0.24 −0.55 0.54 0.04 0.19 −0.15 −0.07 Zn, mg kg−1 0.34 −0.11 0.75 0.05 0.17 0.20 0.17 P, mg kg−1 0.06 −0.02 0.73 −0.21 −0.29 0.10 0.04

CM, % 0.14 −0.32 0.45 −0.25 −0.02 −0.33 −0.26

CEC, cmol kg−1 −0.00 0.02 −0.15 0.86 0.03 −0.05 0.10 Cu, mg kg−1 0.44 0.07 0.00 0.71 −0.37 0.15 0.06 WY, Mg ha−1 0.07 −0.02 − 0.07 −0.03 0.72 −0.09 0.12 Silt, % 0.05 0.19 −0.10 −0.31 0.54 0.29 0.25

SOM, % 0.07 0.17 0.42 0.10 0.53 0.08 −0.22 K, mg kg−1 −0.05 0.24 0.17 −0.10 −0.12 0.82 −0.06 B, mg kg−1 −0.23 0.31 0.00 −0.18 −0.37 −0.62 0.18 Cd, mg kg−1 −0.04 0.02 0.04 −0.01 0.05 0.08 0.87

PR, KPa 0.15 −0.02 −0.01 −0.13 −0.07 0.28 −0.58 Variance, % 16.95 16.27 10.96 8.29 7.19 6.88 6.68 Cumulative variance 16.95 33.22 44.18 52.47 59.66 66.54 73.22

EC, electrical conductivity; HC, hydraulic conductivity; CM, coarse material; CEC, cation exchange capacity; WY,

Finally, wheat yield and penetration resistance were loaded in Factor 9 and it was named as "crop yield factor". The crop yield factor described 4.46% of the total variation. Loadings

Similar results were found elsewhere, PR reduced wheat and soybean yields [57]. Others [58]

= −0.735) between these two variables in the study area.

wheat yield; SOM, soil organic matter; PR, penetration resistance.

**Table 9.** Factor analysis for subsoil in study area.

showed a high negative correlation (*R*<sup>2</sup>

penetration resistance were in the second group for Entisols.

108 Land Degradation and Desertification - a Global Crisis

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Factor analysis revealed that PR in topsoil had a profound adverse effect on wheat yield, whereas silt and SOM content in subsoil had a positive effect. A moderate positive correlation occurred between PAWC and wheat yield. Therefore, insufficient water-holding capacity, low SOM content, and high PR are the major variables affecting wheat yield in the catchment. These variables can be controlled by management practices such as residue management, crop rotation, and use of organic materials in crop production. Soil loss is one of the major contributors to soil degradation. Our results showed that 89% of the study area is under the influence of surface runoff to some degree. Conservation tillage (CT) can be adapted to decrease the potential of surface runoff in the study area. However, CT should be applied carefully to the areas with high PR, since it can also increase PR.

In combination with crop rotation and variable fertilizer application, these practices can help restore soil productivity in cultivated areas, which cover 95.4 ha of the study area. Forage crops should be used in crop rotation to increase SOM content and decrease PR in the study area. It is likely that increasing SOM and decreasing PR will decrease surface crusting, which would increase water-holding capacity by increased water infiltration into soil and decreases the potential for soil loss through surface runoff. The localities covered by grass and shrubs should be managed properly to avoid further deterioration. This may be accomplished by the application of rotational grazing, which reduces animal trafficking, in turn decreasing PR in grasslands.
