Grazing Effects on Soil Physical and Chemical Properties

Uncontrolled grazing can have deteriorative effects on soil properties. This paper studied the effect of different grazing intensities on soil physicochemical and hydraulic properties at Al-Khanasry Agricultural Station, Al-Mafraq, Jordan. In summer 2016. Treatments were (1) no-grazing (NG), (2) controlled grazing (CG), and (3) uncontrolled grazing (UnG) sites. Soil samples were collected from each site to determine bulk density (BD), aggregate stability (AS), soil organic matter (SOM), electrical conductivity (EC), soil acidity (pH), and cation exchange capacity (CEC). Infiltration (F (t)) and hydraulic conductivity (HC) were measured in the field. Results showed that UnG significantly increased BD, Controlled and un-controlled grazing sites showed similar BD (P=< 0.05), the highest was in controlled grazing (1.47 g cm-3). Aggregate stability also increased under grazing condition (P=< 0.05) only in the surface layer (AS), The lowest AS in surface layer was observed in no-grazed plot (17.4%), while no significant difference (P=< 0.05) were observed between controlled and un-controlled grazing plots (24.6 and 24.8%), respectively. In significant (P=< 0.05) Grazing increased soil OM in surface layers. Un-controlled grazing area had significantly (P=< 0.05) higher OM content (3.5%) compared to the no-grazed, but not significant (P=< 0.05) from the controlled grazing area (3%). Grazing significantly decreased F(t) and HC when compared to NG. Grazing significantly (P=< 0.05) reduced cumulative infiltration. The highest cumulative infiltration was observed in no-grazed area while the lowest was in un-controlled grazing area. Also, significant results showed that Grazing reduced (HC), however no significant (P=< 0.05) differences were observed between controlled and un-controlled grazing areas (P=< 0.05). The higher HC was in no-grazed site (0.172*103 cm s-1) while the lowest was in un-controlled grazing area (0.034*103 cm s-1). Therefore, controlling grazing intensity is recommended in these dry areas.