Agriculture Reference
In-Depth Information
Root hair cell
Endodermis
Primary xylem
Apoplast movement
Symplast movement
Primary xylem
Soil particles (colloids)
Cortex
Pith
Primary phloem
FIGURE 5.1
Cross-section of root with uptake of water and minerals from the
nutrient solution into the vascular system. (Drawing courtesy of George Barile,
Accurate Art, Inc., Holbrook, New York.)
in an atomic ionic state. This is the nutrient solution that contacts the plant
roots providing the elements that are taken up with differential uptake
in the same way as for the soil solution. The difference between hydro-
ponic and soil cultivation is that in hydroponics we add exactly the correct
amounts in the optimum ratios of each element so that plant growth is not
restricted as it might be in soil when some of these essential elements may
be at nonoptimum levels. When growing hydroponically, we use bioagents
and beneficials as discussed in the previous chapter so our products are
pesticide free. This is termed integrated pest management (IPM).
SOURCES OF ESSENTIAL ELEMENTS
In most cases the indoor hydroponic hobbyist will purchase his nutrients
prepared from one of the hydroponic outlets. Generally, the nutrients come
in two components, an A and B formulation. Two separate components
prevent any chemical reaction from taking place in their concentrated
form. Usually one part will contain calcium, nitrogen, potassium, and iron,
whereas the second one contains the remaining elements. Dissolve them in
water separately to prevent any precipitation. The normal ingredients con-
tained in part one (A) include calcium nitrate, potassium nitrate, and iron
