Which of the following is NOT a characteristic of healthy soils?

Healthy soils exhibit several key characteristics that support plant growth and environmental quality. One of these characteristics is a diverse ecosystem, which includes a variety of organisms such as bacteria, fungi, insects, and worms. This biodiversity plays a crucial role in nutrient cycling, pest control, and the overall health of the soil.

Another important attribute of healthy soils is their high nutrient levels. Nutrients such as nitrogen, phosphorus, and potassium are essential for plant growth, and healthy soils typically hold an adequate supply of these nutrients in forms that plants can readily absorb.

Good water retention is also a hallmark of healthy soils. Soils that can effectively retain water help plants access moisture, especially during dry periods, and contribute to groundwater recharge.

In contrast, a compact structure is not a characteristic of healthy soils. Compact soils can restrict root growth, limit water infiltration, and hinder air circulation, all of which are detrimental to plant health. Therefore, a compact structure does not align with the ideal attributes of healthy soils, making it the correct choice in this context.