Agriculture Reference
In-Depth Information
3
The Nutrition of Grapevines
The Essential Elements
Grapevines must have 16 of the 118 known elements to grow normally, flower, and
produce fruit. These essential elements, listed in table 3.1, are also called nutrients
and as such are divided into
• Macronutrients,whicharerequiredinrelativelylargeconcentrations
• Micronutrients,whicharerequiredinsmallerconcentrations
Box 3.1 discusses the different ways of calculating nutrient concentrations in
soil,plants,andliquid.Vinesdrawmostoftheirnutrientsfromthesoil,andso
table 3.1 also shows the common ionic form of each element in soil.
Ions, the charged forms of elements, are introduced in box 2.4, chapter 2. For
example, carbonic acid (H
2
CO
3
), which is a compound of carbon (C), hydrogen
(H), and oxygen (O), dissociates in water into the ions H
+
and HCO
3
−
. This is a
chemical reaction that can be written in shorthand form as
↔+
+
−
HCOHHCO
2
3
3
The double arrow shows that the reaction can go either forward (to the right) or
backward (to the left), depending on the concentrations
1
of H
+
and HCO
3
−
relative
1
he concentration of H
+
ions in a solution at pH 5 is 10
-5
molar(M),equivalenttooneH
+
ion per
100,000 molecules of water, which is 10 times greater than the concentration of H
+
ions at pH 6.
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