Which property of soil refers to its ability to hold and exchange cations?

Cation exchange capacity refers to the ability of soil to hold and exchange positively charged ions (cations) such as calcium, magnesium, potassium, and sodium. This property is crucial for soil fertility because it directly impacts nutrient availability to plants. Soils with high cation exchange capacity can retain nutrients more effectively, making them more accessible to plant roots. This characteristic is influenced by soil texture and organic matter content, as both can enhance a soil’s ability to retain and exchange cations.

In contrast, pH measures the acidity or alkalinity of soil, which can affect nutrient availability but does not directly refer to the ability to hold cations. Salinity indicates the concentration of soluble salts in the soil, which can affect water availability and plant growth but is unrelated to cation exchange capacity. Texture describes the size distribution of soil particles (sand, silt, clay) and affects drainage and aeration but does not specifically measure the soil's ability to retain and exchange cations. Thus, cation exchange capacity is the property that specifically addresses the retention and exchangeability of cations in the soil.