Presenting the first book to focus on the importance of silicon for
plant health and soil productivity and on our current understanding
of this element as it relates to agriculture.
Long considered by plant physiologists as a non-essential
element, or plant nutrient, silicon was the center of attention at
the first international conference on Silicon in Agriculture, held
in Florida in 1999.
Ninety scientists, growers, and producers of silicon fertilizer
from 19 countries pondered a paradox in plant biology and crop
science. They considered the element Si, second only to oxygen in
quantity in soils, and absorbed by many plants in amounts roughly
equivalent to those of such nutrients as sulfur or magnesium. Some
species, including such staples as rice, may contain this element
in amounts as great as or even greater than any other inorganic
constituent. Compilations of the mineral composition of plants,
however, and much of the plant physiological literature largely
ignore this element. The participants in Silicon in Agriculture
explored that extraordinary discrepancy between the silicon content
of plants and that of the plant research enterprise.
The participants, all of whom are active in agricultural science,
with an emphasis on crop production, presented, and were presented
with, a wealth of evidence that silicon plays a multitude of
functions in the real world of plant life. Many soils in the humid
tropics are low in plant available silicon, and the same condition
holds in warm to hot humid areas elsewhere. Field experience, and
experimentation even with nutrient solutions, reveals a multitude
of functions of silicon in plant life. Resistance to disease is
one, toleration of toxic metals such as aluminum, another. Silicon
applications often minimize lodging of cereals (leaning over or
even becoming prostrate), and often cause leaves to assume
orientations more favorable for light interception. For some crops,
rice and sugarcane in particular, spectacular yield responses to
silicon application have been obtained. More recently, other crop
species including orchids, daisies and yucca were reported to
respond to silicon accumulation and plant growth/disease control.
The culture solutions used for the hydroponic production of
high-priced crops such as cucumbers and roses in many areas (The
Netherlands for example) routinely included silicon, mainly for
disease control. The biochemistry of silicon in plant cell walls,
where most of it is located, is coming increasingly under scrutiny;
the element may act as a crosslinking element between carbohydrate
polymers.
There is an increased conviction among scientists that the time is
at hand to stop treating silicon as a plant biological nonentity.
The element exists, and it matters.