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Advances In AGRONOMY Vol. 38

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This volume continues the international focus of Advances in Agronomy. Scien-
tists from six countries are among the authors of the nine papers included. They
remind us of the universality of agronomic problems and of the attempts of
scientists to solve them.
Four of the contributions are concerned directly or indirectly with the physical
properties of soils. One describes how the spectral properties of soils and their
vegetation are being used in satellite imagery programs. A second summarizes
our knowledge of spatial variability of soils-a topic of both practical and
scientific significance. Recent investigations on the effects of soil structure on
water movement and root growth are covered in a third. The fourth is concerned
with the quantity and nature of hydrocarbons in the soil air, a subject of consider-
able importance, especially in soils that are not too well aerated.
Chemical reactions in soils and clays are reviewed in two other chapters. One
focuses on the reactions taking place on variably charged surfaces, a relatively
understudied subject and one of special significance in some soils of the tropics.
The application of chemical kinetics of soil systems ST covered in a second,
which reviews our understanding of the mechanisms of ionic reactions in soils
and clays, and the rates at which they occur.
The surprisingly positive role of certain pesticides on nitrogen fixation in soils
is reviewed in another contribution. Research suggests that certain soil organisms
that prey on or compete with the nitrogen-fixing bacteria are controlled by these
pesticides, thereby freeing the bacteria to fix more nitrogen.
Of the two chapters that specifically consider crop production, one focuses on
weed control, namely research on several methods of weed control in dryland
(upland) rice. This information will be especially helpful to scientists in develop-
ing countries where weeds severely restrict dryland rice production.
The second crop production chapter provides a brief review of rice-based
cropping systems in the People's Reublic of China. It gives a description of
certain extremely intensive farming systems used in China, some of which have
been modified in recent years in response to economic and agronomic factors
Our appreciation is expressed to these crop and soil scientists for providing
their interesting reviews.

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Availability

10015/38

631(058) ADV a

Perpustakaan PPKS Medan Lt. 1 (631)

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Detail Information

Series Title

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Call Number

631(058) ADV a

Publisher

New York : Academic Press., 1985

Collation

xi, 375 hal.: ill; 23 cm

Language

English

ISBN/ISSN

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Classification

631(058)

Content Type

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Media Type

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Carrier Type

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Edition

38

Subject(s)

agronomi

Specific Detail Info

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Statement of Responsibility

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