Agriculture Reference
In-Depth Information
100
90
80
70
clay
60
50
silty
sandy
clay
clay
40
silty clay
loam
clay loam
30
sandy clay loam
20
loam
silt loam
sandy loam
10
loamy
silt
sand
sand
sand (%)
A textural triangle based on the USDA particle-size classification (similar to that used in
Europe) (Soil Survey Manual 1993). Reproduced with permission of the USDA.
Figure 2.3
Soil Texture and Vineyard Soils
Texture influences soil behavior in several ways, notably through its effect on soil
structure, water retention, aeration, drainage, temperature, and the retention of
nutrients.
2.2.2
Texture and Soil Water
Clay particles are very important for aggregation and hence soil structure, which
in turn influences water holding capacity, aeration, and drainage. Good aeration
and drainage are important for vines. Fine- and medium-textured soils, such as
clays, silty clays, and clay loams, are called “heavy textured”: they have higher wa-
ter holding capacities than sandy soils. But unless they are well structured, they
are unlikely to drain as quickly as sandy or “light-textured” soils. Gravel and stones
make a sandy soil even more free-draining, but also lower the soil's water hold-
ing capacity. An example of a very freely drained, gravelly soil used for vine grow-
ing in the Lodi District of California was shown in figure 1.7.
2.2.2.1
