Agriculture Reference
In-Depth Information
Vineyard Management
Nutrition
Grapevine nutrition is an important part of grape production with implications on
vine growth and berry composition. The acquisition of nutrient is influenced by
the soil environment, particularly soil moisture and temperature. The uptake of nu-
trients from the soil solution requires energy from stored or recently assimilated
carbohydrates for further root growth to explore more soil volume and for the ac-
tive nutrient uptake necessary for several nutrients. The inorganic macro and micro
nutrients (based on concentration in plant material) are essential for plant growth.
Nutrients are important as structural components, and are involved in energy trans-
fer reactions, activation of enzymes or metabolic processes. Nutrients can also be
taken up by the leaves via the cuticula by diffusion, allowing for foliar fertiliser
application often used for some micro nutrients in grape production.
Nitrogen (N) is part of number of organic compounds and is taken up in the form
of a cation as ammonium (NH
4 +
) or an anion as nitrate (NO
3 −
). The uptake depends
mostly on the presence of the ions in the soil solution. In grapevines, NO
3 −
is the
primary source of N due to the high nitrification rates in vineyard soils. The vine
xylem contains NO
3 −
and glutamine is the dominating amino acid. The amino-N
can be translocated via the phloem to growing organs or to the storage tissue to be
available when nutrient uptake is low.
Based on the concentration in plant tissue the elements N, P, K, Mg, Ca and S
generally defined as macro nutrients (Marschner
2012
). N, Mg and S form part of
the chlorophyll molecule and are for the production of sugars by the photosynthetic
process. The elements N and S are also components of proteins, while Ca is part of
cellular structural components and P of cell membranes. The later is also important
for high energy bonds required for the transfer of energy within cells and between
organs of the grapevine. K has an important role in carbohydrate metabolism and
transport as well stomatal functioning, regulating the movement of water in grape-
vines (Keller
2010
). Other essential elements Fe, Mn, Zn, B, Mo and Cu, and are
classified as micro nutrients and are generally present in lower concentrations than
the macro nutrients. Fe, Mn, Zn and Cu are involved more or less in the assimilation
process, by either involvement in the chlorophyll synthesis (Fe and Cu), chloroplast
development (Zn) or involvement in the light reaction (Mn). In addition, Fe and Mn
activates enzymes and Cu is present in enzymes. Zn and Mo have a role in the N
metabolism, in either synthesis of proteins (Zn) or the conversion of nitrate N taken
up by the roots to useable forms (Mo), while B has an important role in carbohy-
drate metabolism.
The phloem mobility of nutrient varies and is an indication to what extent these
nutrients can be remobilised from reserve tissue or from older tissues into devel-
oping organs. Differences in nutrient mobility are observed when deficiencies are
present. The classification of phloem nutrient mobility has been determined by as-
sessing the concentrations in the phloem or by using labelled elements (radioactive
