J. Jpn. Soc. Soil Phys.
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*ῌ**Improvement of Subsoil under Tea Field by Rotor-Bucket Machines
Masaharu KOMAMURA* and Shoichi GOTO*** Faculty of Regional Environmental Science, Tokyo University of Agriculture** Shizuoka Tea Experiment Station
Abstract
Declined land has been reclaimed as a tea ﬁeld in Shizuoka Prefecture, Japan. We examinedthe e#ects of mixing tillage by rotor-bucket machine on improvement of subsoil under theseﬁelds.
+.

Some of the results obtained are as follows :Thickness of both A and B horizon of the soil proﬁle increased by mixing tillage byrotor-bucket machines.
,.

The content ratio of soft-rocks decreased by this treatment and the hardness of soil alsodecreased.
-.

Physical properties throughout the soil proﬁle were improved especially in three-phase

distribution.
..

Mixing tillage by rotor-bucket machine enhanced the growth of ﬁne roots and yields of tea.

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22

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ῌ1²³´ ./012´Fig. 3

Proﬁle of soil macro-pore in bucket test
ﬁeld (µ) and rotor-bucket ﬁeld (¶).

Fig. +*

Proﬁle of soil micro-pore in bucket test
ﬁeld (µ) and rotor-bucket test ﬁeld(¶).

Fig. 1 Three phase distribution of the bucket
test ﬁeld.

ῌ+*ῌ2Fig. 2²³´ 345./012

Three phase distribution of the rotorbucket test ﬁeld.

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Fig. ++

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°>Relationship between macro-porosity
and saturated hydraulic conductivity.
(± : bucket test ﬁeld, ² : rotor-bucket
test ﬁeld)

23

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