Page 6 - Enzymes in Tropical Soils

Enzymes in Tropical Soils v

PREFACE

S
oil enzymes are produced by soil microorganisms, soil macroorganisms
(earthworms), and plant roots. In soils, these biochemical compounds are
biocatalysators. Their roles are uniques; enhancing the release of plant
nutrients from soil organic sources not available to plants to be inorganic
elements readily available to plants. One of the various soil enzymes is soil
phosphatase that plays important roles in the transformation of organic
-
2-
phosphorus that is not available to plants into orthophosphates (H 2 PO 4 dan HPO 4 )
that are available to plants. By the above reason, the presence of soil enzymes are
of great importance in availing particular plant nutrients from organic sources.
Their presence may decrease the need of these nutrients supplied by inorganic
compounds (soil minerals, chemical fertilizers, etc.).

The book of Enzymes in Tropical Soils is a critical summary of research results
conducted by the author since 1995, at the time he participated in a postdoctoral
program in Nagoya University, Nagoya, Japan, and by researchers all over the
world, that have published their research results in the field of soil enzymes. This
book is composed of 12 chapters. Chapter I exposes the importance of availing
plant nutrients in the soil-plant system, that partly involves soil enzymes. Chapter
II deals with the general theoretical aspects related to enzymes. Chapter III
describes the role of enzymes in the cylcling of some nutrients in the soil-plant
system. Chapter IV exposes some of the important enzymes present in the soil-
plant system. Because soil enzymes are affected by soil internal and external
factor, some important factors are discussed, particularly the influence of organic
matter contents (Chapter V), soil water and temperature (Chapter VI), soil reaction
(Chapter VII), and some plant nutrients (Chapter VIII), and also the presence of
toxic heavy metals (Chapter IX). Discussion will be continued by exposing the effect