Pedology and Edaphology are the two divisions that make up the study of soil, otherwise referred to as "soil science." Along with climate, temperature and exposure to sunlight, soil is one of the 4 most important natural factors that affect the quality of grapes and their resulting wine.
What is the Difference Between Pedology and Edaphology?
The study of soil is highly complex. The first division of soil science, pedology, looks at the history and formation of different types of soils, studying their evolution over time. It is pedologists who are responsible for the classification of the different types of soils, something that is very useful to viticulturists.
The second division of soil science, edaphology; it focusses on the interaction and influence of soil with living organisms, particularly plants. (Learn more in "Soil Types and the Wine Grapes That Grow Best in Them.")
Why is Soil so Important in Viticulture?
The first things that normally come to mind when considering which soils might provide a healthy crop of grapevines and fruit are water and nutrients.
The type of soil a vine is planted in will have a large effect on the nutrients the plant receives and therefore the vigor of its growth. While soil itself doesn’t actually provide water, its composition affects the rate at which water drains, thus determining the amount of time roots are in contact with (and able to extract) water.
Besides nutrients and water, soil also provides anchorage for vines. This can be particularly important in regions where high speed winds are prominent.
Soil also helps regulate the temperature of vines. Darker soils, and soils that contain large boulders, absorb heat during the day and retain it through to the night. This is helpful in cooler viticultural regions. Otherwise, lighter, reflective soils can help avoid an increased temperature in the vineyard, while at the same time increasing sunlight exposure to vines.
Types of Soil in Viticulture
The type of soil a vine is grown in can have a profound effect on the resulting wine. Therefore, it is important to understand the different types of soil and what effect they have on the grapes that are used to make the wines:
Sandy soils drain well and offer good heat retention. In warm viticultural regions, sandy soils produce softer, lighter wines with less color. In cooler climate regions, the soil’s heat retention helps produce highly aromatic wines.
Silt soils retain both water and heat and are very fine, however, these attributes can make it very difficult to grow and establish roots. Wines made using grapes from vines grown in silt soils tend to be smooth with low acidity.
A mix of silt, clay and sand as well as an organic matter known as humus, loam soils are highly fertile, encouraging vigor. They are too fertile, in fact, to produce high quality wine, instead offering wine of very little flavor and color. Rigorous pruning is therefore essential in vineyards grown in loam soils.
How Do Pedology and Edaphology Affect Viticulture?
Given the substantial effect that soil has on the quality of wine, it’s vital for viticulturists, vineyard managers and enologists to understand what they are working with. Through the studies and classifications of pedologists and edaphologists, winemakers now have an advantage when deciding what variety of grape to grow in any given vineyard.
By understanding the different types of soils and what effect they have on wine, winemakers can be confident that they are growing the correct vine for the soil of their vineyards. This, in turn, ensures that their wine is of the highest quality possible for the location in which it was produced.