Impact of Land Use Change on organic Matter Content and physical properties of soil in Bukik Pinang-Pinang under Tropical Rainforest, Mount Gadut West Sumatra.

ISBN

: 978*g7g*g38g*t

E-d

SEMINAR

NASTONAL

DAN

RAPAT

TAHUNAN

N[,I{AN

Biclang

IImu-llrnu

f=ertanian

Badan

Keriasarna

Perguruan

Tingggi

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(BKS-PTN)

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trmpact of Land Use Change otr

organic Matter

_{Content and physical} properties

of

soil

in

Bukik

Pinang-Pinang _{under Tropical Rainforest,}

Mount

iadut

west

snmatra

so'pnYvtf

:ffi illg}ffiTffi:.;#,ffi'#,',lii',",.,,*

*) _{Email :}

ita*lamsoeddin@yahoo. cam

ABSTRACT

(A

stufu

about soil _{organic matter vflrrytt?n and soil physical properties as affected by}

land use

change hcd been conducted

in

in

Bukik Pinang-Pinnng,

trapial'ratn

for"st""areo.

_{The area is}

Iocated approximat-ety

?0

km

from

padang

"ity

gdb.z9'40,'_Ia0%0,20,,

E

and

0o54,ss,,_

0"55'45" _{s), wtth oltttude 38a-640 m}

asl.

_rhts

aria

_{is known}

as the wettest

part

in Indonesia, even

in the world' due

to

its high qrnual

roinfall yhich

_{is ap}

to

_6s00

mm/y.

_{The water}

Jlows dawn to Padang

city

through Batang

Kuranii,

one

of

_{the biggest rivers passing the}

city.

_Bukik pinang-Pinang and the surroundings _{fwrction as}

hyirotog,,iigaowyni

_tlre

diwn

"rriron*"nt,

therefore

it

must be well-managed. The obiective

af

the

reseirch

was

to

determine

soil

organic matter content and physical properties at three

dffirent

types of land use in Bukik pinang-pinnng. Soil organic matter content af non-forest land use (mixei

neis

and bush tand) tendei to ne higher than forest ecosystem. Fuwhermore, soil texture on _{theforest and bush}

kndiasfii,

_{ilr"n on the mixed}

perennial

trees.

Bulk

_density

and

_{total porosity}

of

_the

soil

was eategirized

as

medium, and permeability was considered asfast

for

each land usi.)

Keywords z Roinforest, land _{use change, soil organic matter cofttent,}

soil physical properties

IITTRODUCTPfl

Land use change has intensively happened _{lately in developing countries. The changing is}

not only _{limited to urban} areas, but also _{to rural} areas,

iven

in remote areas _{which is considered as}

conservational

region.

_{The changing can}

!9

{om

farming land

to

non-ug.i;uiiurul purposes or from virgin ecosystems (forest)

toiultivated

land or even oaie land. _{The lasi is conducted illegally}

which often happens in remote areas, _{aiming to cut the wood without replantinj it,}

,urt

as in Bukik

Pinang-Pinangarea-

_Based on Agus (2005) intensive land use change in Indonesia has been started

since last

few

decades. Therefore,

fertile

_{agricultural land continuously reduced}

by years.

_As reporfed by

Irianto

Q}aq

_{that around 22,0A0 ha rice}

field in

Java island was conversed during

1987

-

1993' Even,

it

has reached 100,000 ha

ofrice

field that had been _{conversed by the end}

of

year 2040.

Bukik

Pinang'Pinang

is

located approximately

30

km

from

padang

city

(100.29,40',-100"30'20"

E

and 0o54'55--0"55'45- _{S),-on altitude 480-64.0 m}

asl.

_This

area is known as the wettest part

in

Indonesia, even

in

the

world. It

receives up

to

6500 rnm/y

6asyiOin,

l9g4).

In

climate classification'

t!it^u.tuj.

grouped _{jnto '4fo}

-

_{Amatyp-" umeo on}

ropp*,--ina

^nA

based

on-oldeman (Ogiono,

_1934). Therefore,

it

is c;lled ur

rupo

wet tropical rain

forest.

The water collected on the area flows down to _{Padang ci,ty through Batang Arau, one}

of

_{the biggest rivers}

passing the

city.

Since

Bukik

Pinang-Pinang

is locatel

_on

theligher

_{altitude, the area and}

the

surroundings function as hydrology regulatoi

for

the dor,vnward _{environment, especially} padang

city, the capital

of

West Sumatra. Therefore,

it

must be well-managed

to

_{avoid natural disaster,} such as flood and land slide during rainy season as

well

as drough:t during

of

,**on,

_which

threats our sustainable environment.

Manggis, cinnamon, cacao,

Duh)

and some was abandon and grown

by

_{bush. whether the}

condition changed _{the organic matter content and}

the soil physical properties of the soil or not was

interested to

know'

soil

organic matter colfient and physicai property-determination _{are important} as a data base

for

finding

out

the _{best management applied}

tr

ttt"

t*0.

rhe

oujective

of

the

research was _{to determine soil organic matter content an-f soil physical}

pr"e"ni*

at three different land uses in tsukik pinang-pinang.

MATERIALS

_AF{D

METHODS

Survey rnethod was employed firr this researclq and the soil was

ran

omly sampled

in

each

land use _{(purposively random sampling) on}

0-20

_{and 20-40 cm depth.}

Thr;.

tp",

of

land use in

the area were primary fu1"l, _Gn the top,

*

635440

m

asl,l0o slope, and on the middle, + 570-5g5

m asl, 18-22 slope), bush land (+ 590-600

m asl,4-22

siope),

ryd

mixed perennial trees (

*

390-398

m

asl

with

t

8o

slope).

satellite soil sampier

*"r

dt*_for

_{soil texture (sieve and pipette}

method),

soil

organic matter

(walkley an{

Biack

_{method), then undisturbed}

soil

samples for permeability _{(constant head rnethod based.on}

Darcy's

ra*y, bulk

densi,f

ano

totat

porosi,ty

(gravimetric

urethod).

soil

sarnples were dried and unrtvruo-in soil scienci tauoratooy, _Andalas

University. _{Data from the analyses were compared}

to criteria of soil characteristics.

REST]LT

A}[D

DISCUSION

A.

Soil Organic

Matter

Content (SOM)

tand

use _{change frorn forest into bush land and mixed perennial}

trees did not decrease the

soM

content, even

it

increased _{at foot slope (Fig.}

l).

_Higher

soM

content under mixed perennial trees at foot slope was possibly due

to

the

nrnition or

iire _{under storey plants covering the soil}

surface.permanently.

-Peoplg planting the trees never cleared the surface as

well

as cultivafed the

soil'

since the sunlight _{reached trre soit surfaceo the}

oM

_derived

from the under storey plants was decomposed faster and contributed

to

soM.

A

partrro* tr*t,

_trt"

p"r**"otry

pi*t"o

area with

perennial kees

for

a

long

time

had stabilized

the

"*itot**t

as

it

almost reached

a

forest

ecosystem' _{Therefore, forest area after being}

or

cleared rnust be replanted

i"

ord*

to

reach ths

same environment to the forest agarn, in orderto keep sustainable environment.

under _{forest ecosystem, otherwise, the}

soM

_{derived from}

trees _{was accumulated on the} soil surface up to 10 cm

high.

It was slowly decomposed due to high moisture

*oio*

_temperature on the soil

surhce.

Different weather condition

;d* d;ny

_{foiest was caused by the effect}

of

plant canopy

which is

quite dense that

limit trrr

r*riirii-il'.ea"h

the

soil surface.

Theno low

sunlight rneans low evaporation. _{Since the area has high} 5.0

s

4"0

;

3.0

o

2,0

ea

1.0

0.0

ffiffiffi

Prirnay fmst

Gru

2040

&20 20-10

cm

cIn

cm cm

Bushland Mixeed parennbl

Trs

os

&40

cln cm

Lrnd lJse

[image:3.612.4.603.11.832.2]

rainfall

annually,

low

evaporation keeps

the

soil

surface

quiet

humid.

Therefore,

as

the consequence

of

the-condition,

the

organic

-matter decomposers worked

slower. As

found by Yulnafatmawita et al., (2003) that land _'rse change from foiest into pasture for about 100 years in rainforest area

in

_{Queensland Austmlia} did _{not show significant different}

of

_{the SOM content on}

the top 0-20 cm depth. In adjacent site to Bukik Pinang-pinun

g,

that is Bukik Gajabuih, the

SoM

content

of

the primary _{forest was lower than that in bush land and mixed}

p.r"rriiul

_{tree types}

of

land use _{(Yulnafatm awit4 et al., 20A7).}

Furthermore, from _{Figure 3 also showed that SOM content}

of

_{the soil decreased from the}

top 20 cm

depth

into 2a40

cm

depth

for

each land

use. As

soil

organic matter sourc€ was

primarily from

above ground, the organic matter content

of

the

soil

direased by

lower depth

within soil

profile.

It

was also

found

to

be true

in

Bukik

_Gajabuih

for

_each

land

use

(Yulnafatmawit4

et

a1.,2007), the SOM content decrease at deeper

roil

luy.r.

Higher amount

of

SoM

content

in

soil profile

is

really

expected

to

increase organic

carbtn

sequeshation

or

to decrease carbon content

(C02

concentration)

in

atmosphere. Carbon dioxide was one

of

the greenhouse gas which gives the _{highest contribution to global warming (AGO, 2002).}

B.

Soit Physical Properties

1.

Particle Soil Distribution and Soil Texture

As shown in Figure 2, soil on the tg,p of higher slope _{are4 under primary forest ecosystem,}

was dominated

by

fine particles

(clay).

The lower the aititude tended

io

Oe ttre coarser the soil

particles.

The soil under mixed perennial trees (on foot slope) was dominated

by

silt.

The soil texture on the top forest as

well

as under bush land on the middle slope was classified into clay,

while

on the

foot

slope was loam (based on texture triangle

by

USDA). ttre

difference

in

soil texture among the land use much depends on the parent

materials.

Based on Wakatsuki et ol. (1986) the

soil

on

this

area was

still

newly developed (order Incepisols),

with

suborder

Lithic

Dystropept' Lithic EutroPePt, and' Typic Dystropept on the

top.

While on the-foot slope, soil texture

was much affected by the _{river @atang Lantiak)} passing _{ttrougtr the area.}

The area on

tl9

foot slope having coarse soil texture fraO frigh infiltration _{rate compared to}

the other two types

of

land use (Yulnafatmawit4

et

_al.,2009).

Hig[ infiltation

_{means low}

runofi

and high chance of SoM

gget

into deepel soil p_rofile _{and sequestered in soil, as a consequen! low}

possibility

of

erosion.

Theno

the function

of

the

area

as

a

regulator

for

hydrology

can

be

maintained.

The pattem

of

soil particle size distribution on upper soil profile was also found

o n

the

lolver

layer.

For primary forest and food land, the particies

of

the soil were dominated by clay.

Clay content

for

each land use tended to. increase

by

soil

depth.

It

means that migration

of

cUy from upper

to

lower part

of

soil profiles happened

in

each land

use. ]lhis

was

ttiglfv

possible to

happet! since the annual rainfall

of

the areawas very

high.

High

SOM

contentlf

the soil and

^75

+$.

g.g ₅₀

y4

'S

25

0

--Fd

I*i Ff,

0-10 cm

E!

iFe

I ].rq

10-2Q

cm

##

s Sand

r

Sih E Clay

0-10

10-cm

20 cm

0-10

10-cm

?0 cm Frimary Forest Bu$ Land Mixed

Land tlse

Fig.2. Particle size distribution

of

soils in Bukik Pinang-Pinang

2.

Bulk Density and Total Pore

Soil

bulk

density and total pore as shown

in

Fig.

3 and

4

were not significantly different among the types of the land use. This was due to the texture and the OM content of the

soil.

Soil having fine texture

will

have low bulk density (BD) and high total pore, while coarse texture

will

be the vice

versa.

Then, soil

with

high SOM

will

have low

BD

and high total

pore.

Therefore,

even though soil under mixed perennial trees had coarser texture, the values of the bulk density and

the total pore were not significantly different from the other land useo because

it

had higher SOM content compared to primary forest and bush land.

Fine textured soil on the primary forest combined with much roots in soil profile had lower

soil

bulk

density than bush land

use.

The difference could be due

to

the contribution

of

rootso

which was higher densrty in soil under forest than that under bush land. Therefore, even though the

class textured was the same, the bulk density was different.

At

mixed perennial trees, on the other hand, the value of the BD was lowerthan those at other land use, even though it had coarser soil texture. Lower BD of the soil under mixed perennial trees

was due

to

its high

SOM

content.

Soil

organic matter content can reduce

soil

mass per unit volume. Therefore, soil organic matter can modifr textural characteristics of the soils. As reported

by Yulnafatmawita et al (2009) that SOM content did not only decrease soil

BD,

increased total

soil

poreg

but

it

also improved stability

of

aggregates. There was positive linear correlation between SOM content and soil aggregate stability _{{Yulnafatmawita,2006).} Stable soil aggregates

is really important

to

create to avoid aggregate dispersion or degradation as soil

is

introduced to water.

The value

of

soil

BD

is negatively correlated

to

percentage

of

total

soil

pores.

It

can be

o^

'E 6s

5Ct :t ta

SEmlS40 S2gso20.{0 0{0{*D2SS

€R rm €sl

gtFryM,&Fbhnd,l&€€d kw*i

tardlhe

il$m

ffi

0.7,

Fig.

3.

Bulk

&nsi,ty

of

soits

in

Bukik

Pinang

Pinang

Fig.

4.

Tatal

pore

of

soils

in

Bukik Finanp

Pinang

3.

Soil Ferrneability

The rate of water movement

within

soil profile rtnged &om ratlrsr fast

to

fast

$ig.

5). ft

was affeeted by soil texture, SOM, and biopores as

well.

Coarse textwes

witl

irtc,rrease perrneability

rate of the soils due to their high macropores percentage.

&r

the otlrcr hand, fme texture can have

high penneabilfy rate

if

the soil has high SOM cont€nt, or has biopores- Rate

of

pemreabilrty in soil under Bukik Pinang-Pinang were not significantlv

different.

This was due to corltrs€r

t€xtu€

under mixed perennial fiees and high biopores under prirnary forest ecorysfierr" Therefore, bush

land ecorysterns had a bit lower permeability rate, due to frne tesure and low biryores.

s

^66

€6a

4

f,6?

Em

_€

F

ffi

S20

&.S,

,$ff]

S.S

{}fl} Ad}

cln

cm

cm

tn

{m . ctn

Prirrry

Forest

esHard tfixed

Peernid

Tm

[image:6.612.12.604.18.713.2]

20.81

ffiJl

ffil

ffi

t

ffi_J

;teed

ftremid

Trees

14.71 8.7

ffi

ffif

ffiI

ffit

w__j

&$hlald 21.73

ffig\

ffii

ffi_j

R*$ry ftil?S

30.0

E

20.0 a,

>

=

E

$.0

o

E

o

s

_o.o

GZOcrn 2&4Ocm

tend ttse

Fig.

5.

Permeabilify

of

soils in Bukik Pinang-Pinang

Higher permeability rate of top soil than lower layer related to *re difference of,the particle size dishibution and the SOM content of the soils between the depths. As top 20 cm soil in each

land use had higher SOM and lower clay content, the permeabiliq'became higher than that

d

the 20-40 crn soil depth.

CONCLUSION

Based on data during field survey and laboratory analyses, it can be concluded

(forthe

first

set

of

dat*) that land use change frorn fiorest into mixed pererurial trees (after >50 years without

cultivatioq

but

it

was

fully

and permanently covered by under storey plants) and bush land (after approxirnately 20 years left and grcwn by plants without cultivation) terded to increase the SOM cont€nt frorn 0

to40

cm depth. It could be inferred

tha!

perrnanently grown trees with lower plants covering the surface of the

soil is

important to maintain SOM content

of

the cleared forest area.

SOM

content affected

soil

properties.

[,and use

change

in

Bukik

Pinang-Pinang

did

not significantly affect the soil physical properties (soil BD, soil porosi,ty, and soil permeability). The difference of soil texture class among the land use was much attrib,uted on the soil parent materials.

ACKNOWLEDGMENT

Author would

like

to thank DP2M Directorate General

of

Higher Education

in

Indonesia which gave financial support

for this

researcho as

well

as

my

students, especially Dedy

Hanafi,

Suci Betrianingrum, Arief Fauzan Hakim, and Ricci Enrella who helped in field and laboratory work.

REFERENCES

Australian Greenhouse Otfice

(ACO).

_{2OOZ). National GrenhouseGas Inventory 2000

with

Methodolory Supplements. Australian GreEnhouse

Office

Anmml Report.

Irianto,

G. 20M.

Menyoal AIih Fungsi Lahan, Kekeringan, dan Ketahanan. Tabloid $inm Tani. Ogiono, K.,.I{otta, M., Tarnin,

R

dan Yoneda

T.

1984. Forest ecology

of

gunung Gadut Area.

SumatraNafire Shdy (Botany, Kyofio.

[image:7.612.10.601.26.727.2]

Wakatsuki, T", Saidi" A. and Rasyidin,

A.

1986. SoiI

iil

topsquence

ofthe

gunung Gadut tropical

rainf,mst

West Stnnatra

.

Sauth East

Asim

Swdie s 24 (3) : 24 i -2 62

Yulnafa&rra\ilrtq $o, H.ts., Dalal, R-C. and Menzies,

N"W.

20CI3a COs ernission frorn diff,erent

soil

fractiort following physical disruption: Irnplication for tillage practices. Proreeding on the

lfh

Triermicl

Int'l

Sail

Tillage

Res.Org.(ISTRO)

Co{ercna

13-18 July 2CI03, Brisbane

Australia

Yulnaftfinawita.

2006.

Hubungan antara status

C+rganik

dan stabilitas aggegat tanah Ultisol Lirnau Manis Padang

akibat

penggunaan

lahan.

Proceeding Seminar Tahunan BKS 25-28

April

2006, Jarnbi

Yulnafatnawit4 Luki, U., dan Yanq

A.

?W7.

Kajian Sifat Fisika Tanah Beberapa Fenggunaan Latran di Bukit Gajabuih Kawasan lfutan Hdan Tropik Gunung Gadut Padang. J. Solum

Vol.

IV

No-2 Juli 2A07:

8-]9

Yulnafufirawit4 Asmar, dan Enrella,E.

2m9.

Peng$kurarr trnfithasi Tanah B,ukit Pinang-Pinang Kawasan Hutan Hujan Tropik Gunung Gadut Padang Di Laboratorium.

.{

Solum YoL W No.