Page 212 - Enzymes in Tropical Soils

200 Enzymes In Tropical Soils

Decomplexation is a chemical process in which a complex ion release its cations
driven by low concentration of the participating species. For example,
2+
+
-
Zn(OH) becomes Zn and OH .
Decomposition is a chemical process by which the organic and structurally bound
element not available to plants is detached to be ionorganic elements
available to plants. For example, the decomposition of organic P to form
inroganic P (orthophosphates) available for plant root absorption.
Desorption is a chemical process by which an attached ion onto a charged solid is
detached. For example, the detachment of exchangeable Ca on soil solids
2+
to form Ca in soil solution.
Dissolution is a chemical process in which precipitate or mineral dissolve forming
all the related species at concentrations lower than those needed to
compensate the related solubility constant.
Essential Element is an element needed by plants fulfilling 3 reasons: (1) they are
needed in one or more plant physiological processes, (2) if deficient, plant
growth and production will be disturbed, and (3) their physiological
functions in plants can not be substituted by the presence of any other
elements
Field Water Capacity or FC is the water hold by soil matrix at water potential of 10
– 35 kPa.
Free Ion is an elemental species does not associate with any other elemental
3+
-
2+
-
-
species such as Pb , Fe , Cl , NO 3 , or H 2 PO 4 .
Fulvic Acid is a humic substance soluble or do not precipitate in dilute acids after
being separated from Humic Acids
Humic Acid is a humic substance not soluble in dilute acids.
Humic Substance is plant residue that has been decomposed, consisting of three
fractions, each of which is a mixture of several undescribed organic
compounds: Humin, Humic Acids, and Fulvic Acids (Tan, 1986; 1993).
Humin is a humic substance not soluble in alkaline solution.
Intensity Factor is all forms of nutrients most readily available to plant absorption
such as soil soluble nutrients in soil water.
Nitrogen Cycle or N-Cycle is the chain of all the processes of N transformation from
-
+
N 2 in the atmosphere to NH 4 and NO 3 , and then their absorption by plant
roots and transformation to be structural and functional substances in plant

Abdul Kadir Salam - 2014