What characteristic is typical of sandy soils in arid regions?

Sandy soils in arid regions are indeed characterized by their tendency to become alkaline and the accumulation of salts. This phenomenon occurs due to limited rainfall, which does not adequately leach away soluble salts that may be present in the soil. As water evaporates, it leaves behind these salts, resulting in an increase in alkalinity.

In arid environments, soil moisture is typically low, and when evaporation exceeds precipitation, the concentration of salts increases. Additionally, the coarse texture of sandy soils allows for rapid drainage of any infrequent rainfall, further contributing to this salinization process. This characteristic is crucial for understanding soil chemistry and nutrient availability in such regions, as high alkalinity can affect plant growth by influencing the uptake of nutrients.

Other options do not accurately reflect the typical conditions associated with sandy soils in arid areas. Heavy rainfall would not characterize arid regions, and sandy soils are generally coarser, not fine in texture. Furthermore, sandy soils have a lower water-holding capacity, making the assertion of high water retention inaccurate. Thus, the increase in alkalinity and salt buildup due to insufficient moisture is the hallmark of sandy soils in these climates.