Physical and Chemical Variations of the Soil Under Two Desert Shrubs in Tehuacan, Mexico

Abstract

Desert shrubs modify the soil’s physical and chemical properties under their canopies, making it different from bare soil. Knowledge of the bare soil’s physical and chemical properties and their variation under Prosopis laevigata and Parkinsonia praecox is necessary to understand the functioning of desert microenvironments. The objective of this study was to determine the soil structure, temperature, texture, moisture, water-holding capacity, electrical conductivity (EC), pH, organic matter (OM), and orthophosphate (OP) content of bare soil and the variations of these factors under P. laevigata and P. praecox at 0- to 50-cm depths during a seasonal cycle in Tehuacan, Mexico. Soils under the shrubs have more structure, particularly at depths of 0 to 10 cm. The soil properties vary most from 0 to 10 cm along a seasonal cycle under the shrubs. Soils under P. praecox have the lowest temperature, whereas bare soil exhibits the lowest amount of moisture and highest EC. The surfaces of soil shrubs have the highest water-holding capacity, pH, OM, and OP. Sand, silt, and clay content vary with season and depth but not between microenvironments (α < 0.05). Temperature, sand, OM, and OP decrease with increasing depth, whereas clay and EC increase (α < 0.05). Electrical conductivity is the most variable soil property (coefficient of variation > 60%). Significant correlations were observed among the soil properties, with the strongest correlation between OM and OP under P. praecox (R = 9.86; P < 0.05). Cluster analysis of the physical and chemical soil properties yielded three groups (90% similarity).