5.7 Career Connections – Soil Scientist

Plants obtain inorganic elements from the soil, which serves as a natural medium for land plants. Soil is the outer loose layer that covers the surface of Earth. Soil quality is a major determinant, along with climate, of plant distribution and growth. Soil quality depends not only on the chemical composition of the soil, but also the topography (regional surface features) and the presence of living organisms. In agriculture, the history of the soil, such as the cultivating practices and previous crops, modify the characteristics and fertility of that soil.

Soil develops very slowly over long periods of time, and its formation results from natural and environmental forces acting on mineral, rock, and organic compounds. Soils can be divided into two groups: organic soils are those that are formed from sedimentation and primarily composed of organic matter, while those that are formed from the weathering of rocks and are primarily composed of inorganic material are called mineral soils. Mineral soils are predominant in terrestrial ecosystems, where soils may be covered by water for part of the year or exposed to the atmosphere.

Soil Composition

Soil consists of these major components (figure X)

• inorganic mineral matter, about 40 to 45 percent of the soil volume
• organic matter, about 5 percent of the soil volume
• water and air, about 50 percent of the soil volume

The amount of each of the four major components of soil depends on the amount of vegetation, soil compaction, and water present in the soil. A good healthy soil has sufficient air, water, minerals, and organic material to promote and sustain plant life.

Figure 1. The four major components of soil are shown: inorganic minerals, organic matter, water, and air.

Soil Scientist

Figure 2. This soil scientist is studying the horizons and composition of soil at a research site. (credit: USDA)

A soil scientist studies the biological components, physical and chemical properties, distribution, formation, and morphology of soils. Soil scientists need to have a strong background in physical and life sciences, plus a foundation in mathematics. They may work for federal or state agencies, academia, or the private sector. Their work may involve collecting data, carrying out research, interpreting results, inspecting soils, conducting soil surveys, and recommending soil management programs.

Many soil scientists work both in an office and in the field. According to the United States Department of Agriculture (USDA): “a soil scientist needs good observation skills to analyze and determine the characteristics of different types of soils. Soil types are complex and the geographical areas a soil scientist may survey are varied. Aerial photos or various satellite images are often used to research the areas. Computer skills and geographic information systems (GIS) help the scientist to analyze the multiple facets of geomorphology, topography, vegetation, and climate to discover the patterns left on the landscape.”1 Soil scientists play a key role in understanding the soil’s past, analyzing present conditions, and making recommendations for future soil-related practices.

Figure 3. Dr. Alfredo Alvarado Hernández pictured in his office

Dr. Alfredo Alvarado Hernández is a soil scientist currently working at the University of Costa Rica. As Dr. Hernández has expressed, “Costa Rica has extraordinary soil variability in a very limited area” due to the high variation of parent material available for soil formation.

Dr. Hernández’ areas of study and interests are just as diverse as the soil composition of Costa Rica. Most of his work has been directed towards soil-plant relationships, soil compaction on livestock-housing land, and soil nutrient retention. His most recently published work was in 2014 – regarding Inceptisols (a widely distributed soil order) and its mineral content relative to parent material. The research that Dr. Hernández has performed directly supports a greater understanding of ecological change, and a path to more sustainable ways of living for farmers and builders.

If you want to read more about it here is one of his many articles