Final answer:
Loam is not a crucial component of soil; it is a type of soil itself. Soil's essential components are inorganic mineral matter, organic matter, water and air, and living matter, which all work together to support plant growth.
Step-by-step explanation:
The element that is not a crucial component of soil is loam (b). Loam refers to a type of soil that is a mixture of sand, silt, and clay along with organic matter. The four major components of soil that are crucial for plant growth and soil health are inorganic mineral matter, organic matter, water and air, and living matter. These components are integral to providing the right environment for plant life, allowing them to thrive by supplying essential nutrients, a medium for root growth, and the conditions necessary for biological activity.
Soil serves as a foundation for plants, supplying them with water and essential minerals. It is a heterogeneous mixture of varied particle sizes and organic content. Organic content called humus, which is a mixture of decaying organic matter and microorganisms, is particularly important as it enhances the soil structure and its ability to hold water and nutrients. Inorganic soil particles come in different sizes categorized as sand, silt, or clay, each playing a part in soil drainage and nutrient availability. The balance of air and water in the soil also contributes to the biochemical processes necessary for plant life.