Page 191 - Ilmu Tanah

178 The Chemistry and Fertility of Soils under Tropical Weeds

Leaching The vertical movement of chemical substances in soils through
percolating water in the soil pore channels.

Liming The chemical treatment of soil using a particular lime material to enhance
the soil pH and improve its chemical properties (See Alkalization).

Mechanical-Physical Weed Control The method to destroy or to eliminate the
physics of weeds by physical pressure with the objective to kill or inhibit the
growth and propagation of weeds (Sriyani, 2010).

Mixed Plantation Land-use system with multi-vegetation planted on it.

Monoculture Plantation Land-use system with one kind vegetation planted on it.

Natural Enemy A particular animal species which is naturally the predator of a
particular animal or plant species.

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
tissues and microorganisms, and then their ultimate decomposition back to
+ -
form inorganic N (NH 4 and NO 3 ) available to plants.

Optimum pH A pH value at which the activity of a particular soil enzyme is highest.

Oxidation The chemical process in which the oxidation number of an element in
one substance increases due to the loss of one or more electrons released and
accepted by any other substance called electron acceptor.

Percolation is the gravitational movement of water in soil through pore channels.

Phosphorus Cycle or P-Cycle The chain of transformation from Organic P to
inorganic P by decomposition process and absorption of inorganic P through its
re-synthesis in plants to produce new organic matters and back to the
decomposition of organic matters to produce inorganic P

Phosphatase An organic substance produced by microorganisms, earthworms, or
plant roots acting as a biocatalyst functioning to accelerate the detachment of
2-
-
P from organic P to form inorganic orthophosphates (H 2 PO 4 and HPO 4 )
available for plan root absorption.
Abdul Kadir Salam and Nanik Sriyani – 2019