Page 192 - Ilmu Tanah

The Chemistry and Fertility of Soils under Tropical Weeds 179

Physical-Mechanical 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).

Precipitate A chemical compound resulted by precipitation process that occurs at
saturated concentrations of all the related species controlled by the reaction
solubility constant.

Precipitation A chemical process resulting in a precipitate that occurs at saturated
concentrations of all the related species controlled by the reaction solubility
constant.

Preventive Weed Control The method to limit weed investation and to depress
their growth and spreading so that any other weed control method is not
necessary or at least minimized (Sriyani, 2010).

Primary Forest Land-use system with natural and undisturbed vegetation growing
on it.

Protease The soil enzyme functioning as a biocatalyst participating in the
acceleration of protein decomposition.

Redox Reaction A pair reactions containing a simultaneous oxidation and reduction
reactions in which electrons are transferred from the oxidized substances to
the reduced substances.

Reduction A chemical process in which the oxidation number of an element in one
substance decreases due to the acceptance of one or more electrons released
by any other substances called electron donors.

Reductor Any substance that may release one or more electrons and causes any
other substance to accept the electron and be reduced.

Respiration The oxidation of hydrocarbon as an electron donor and O 2 as the
electron acceptor producing energy, water molecules, and carbondioxide
molecules

Root-To-Shoot Ratio An expression of root dry-weight over shoot dry-weight.

Abdul Kadir Salam and Nanik Sriyani – 2019