Download agroekologi temperatur tanah

TEMPERATUR
TANAH:
Perilaku dan Efeknya
bagi Tanaman
Bahan kajian untuk MK AGROEKOLOGI
Soemarno , jrstnhfpub-oktober 2012
TEMPERATUR TANAH
Temperatur atau Suhu adalah
tingkat kemampuan benda
dalam memberi atau
menerima panas.
Suhu seringkali juga
dinyatakan sebagai energi
kinetis rata-rata suatu benda
yang dinyatakan dalam derajat
suhu.
Bahan kajian untuk MK Dasar Ilmu Tanah
Soemarno 2011
Suhu juga dinyatakan sebagai ukuran energi kinetik rata-rata dari pergerakkan
molekul suatu benda. Suhu menunjukkan sangkar cuaca yang dipergunakan untuk
pengamatan suhu. Pengukuran dilakukan dengan menggunakan thermometer air
raksa dan alkohol.
Dengan thermometer air raksa pengukuran dapat dilakukan dari suhu 35o C – 350o
C, hasilnya adalah cukup bagus karena mengingat angka pengembangan air raksa
pada tiap suhu lebih merata dari alkohol, sehingga untuk pengukuran suhu udara
biasanya digunakan thermometer air raksa.
http://blkmtncommunitygarden.blogspot.com/2010/03/soil-temperature-chart-forseed.html
. http://reflitepe08.blogspot.com/2011/03/suhu-udara-dan-suhu-tanah.html …..
diunduh 3/2/2012
Pentingnya temperatur
tanah?
Temperatur tanah
Salah satu sifat fisika tanah yang sangat berpengaruh terhadap proses-proses
dalam tanah, seperti pelapukan dan penguraian bahan organik dan bahan induk
tanah, reaksi-reaksi kimia , dll.
Example of soil moisture and temperature during and after freezing.
(Gravimetrically determined θv was 11.8 % on day 0 and 11.3% on day 9.)
Soil moisture measurement in the Ross Sea region of Antarctica using Hydra
soil moisture probes.
Aaron M. Wall, Megan R. Balks, Dave I. Campbell and Ron F. Paetzold
http://www.regional.org.au/au/asssi/supersoil2004/s15/oral/1502_walla.htm
diunduh 15/2/2012
Faktor-faktor yang mempengaruhi suhu
tanah :
1. Faktor iklim / cuaca
–
–
–
radiasi surya
Hujan
Angin
- Keawanan
- suhu udara
- kelembaban udara
The soil temperature is much less influenced by climatic changes. The
graph shows the variation in temperature over a year at different depths
(0, 2, 5 and 12 feet). As we can see, the temperature fluctuation
decreases with increasing depth.
Sumber: http://www.enviroair.ca/en/geothermal.html..... . diunduh
12/2/2012
Faktor-faktor yang mempengaruhi suhu tanah
:
2. Keadaan tanah
–
–
–
–
–
tekstur tanah
kadar air tanah
kandungan bahan organik
warna tanah
struktur tanah (pengolahan ddan kepadatan
tanah)
Depth dependence of annual range of ground temperatures in Ottawa,
Canada (Williams and Gold 1976, National Research Council of Canada
2003).
Sumber: http://iopscience.iop.org/1748-9326/2/4/044001/fulltext/
diunduh 12/2/2012
Faktor-faktor yang mempengaruhi
suhu tanah :
3. Kondisi topografi
–
–
–
–
kemiringasn lereng
arah lerreng
tinggi permukaan tanah
vegetasi
Definition ofthe Temperature Vegetation Dryness Index (TVDI). TVDIfor a given
pixel (NDVI,Ts) is estimated as the relation between the distance ofthe pixel
from the wet edge (TVDI=O) and the spån ofTs in the Ts/NDVI-spacefor the
given NDVI (the difference between Ts and the dry edge (TVDI=I) and Ts at the
wet edge).
SUMBER: http://www.tidsskrift.dk/visning.jsp?markup=&print=no&id=71866
Diunduh 12/2/2012)
Pentingnya temperatur tanah
1. Temperatur tanah mempengaruhi
aktivitas biologi tanah---- tidak
optimal apabila suhu tertentu tidak
dapat dipertahankan
• Tingkat aktivitas optimum dari
organisme tanah adalah suhu 18
– 30oC
• Kurang dari 10o C: menghambat
perkembangan mikroba tanah dan
menghambat penyerapan hara
oleh akar tanaman
• Lebih dari 40oC : mikroba tanah
tidak aktif, kecuali mikroorganisme
tertentu (termofilik).
PENTINGNYA TEMPERATUR TANAH
2.
•
Temperatur tanah juga menentukan reaksi kimia dan
aktivitas mikroba tanah yang dapat merombak senyawa
organik tertentu menjadi hara tersedia.
Proses nitrifikasi ( temperatur optimum ± 30o C ), yaitu pada
kondisi agak panas
http://info.cycadpalm.com/bid/57663/How-to-Fertilize-Cycads-Part-2 diunduh 15/2/2012
Pentingnya temperatur tanah
3.
4.
5.
Temperatur tanah juga mempengaruhi pelapukan bahan
induk tanah
Temperatur tanah mempengaruhi perkembangan akar,
karena ada hubungannya dengan kelengasan dan aerasi
tanah
Temperatur tanah mempengaruhi pekecambahan biji dan
pertumbuhan kecambah
Effect of soil temperature on nitrate formation (adapted from Fredereick and
Broadbent, 1966).
http://www.ipm.iastate.edu/ipm/icm/2001/10-22-2001/why50.html … diunduh
15/2/2012
Pentingnya temperatur tanah
pertumbuhan tanaman tertentu (jenis berbeda)
menghhendaki keadaan temperatur yang cocok.
http://www.cropinfo.net/AnnualReports/2003/YNSResponsetoEnvironment03.htm.... ..
Diunduh 12/2/2012
SUHU TANAH BAGI CACING
Suhu atau temperatur tanah yang ideal untuk
pertumbuhan cacing tanah dan penetasan
kokonnya berkisar antara 15oC – 25oC.
Suhu tanah yang lebih tinggi dari 25oC masih
cocok untuk cacing tanah, tetapi harus
diimbangi dengan kelembapan yang memadai
dan naungan yang cukup.
Oleh karena itu, cacing tanah biasanya
ditemukan hidup dibawah pepohonan atau
tumpukan bahan organik.
http://biologi.lkp.web.id/?p=604 diunduh 3/2/2012
Dimana suhu tanah diukur?
Termometer Tanah
• Used to take temperatures at
5 and 10 cm depths
PVC
Spacer
PVC
Spacer
Kalibrasi Termometer tanah
Basically, we compare the soil
thermometer to a calibration
thermometer, and adjust the
soil thermometer.
First, we need to check the
calibration thermometer!!
…by dipping it in an ice bath.
Checking Calibration
Thermometer
• Submerge thermometer in
ice-water bath
• Let sit for 10-15 minutes,
stirring thermometer
occasionally
•
Read the thermometer.
If it reads between -0.5°
C and +0.5° C, the
thermometer is fine.
• If the thermometer
reads greater than +0.5°
C, check to make sure
that there is more ice
than water in your icewater bath.
• If the thermometer
reads less than -0.5° C,
check to make sure that
there is no salt in your
ice-water bath.
Kalibrasi Termometer Tamah
• Add the soil thermometer to the ice bath
• Wait 2 minutes
• Read both Soil Thermometer and
calibration thermometer.
• If they agree to within ±2° C, the soil
thermometer is ready to use.
• If not adjust the soil thermometer, using
a wrench, until it reads with ±2° C of the
calibration thermometer
Kapan mengukur suhu tanah ?
• Soil temperature is a weekly
measurement, but you can do it daily.
• Try to do the measurement at about
the same time of day
• Take data near the atmosphere station
or near the soil moisture site
• Also measure soil temperature
measurement whenever a soil moisture
data are taken
• Seasonally (4 times a year), measure
soil temperature every few hours during
the day for 2 consecutive days
– provides a diurnal reading of soil
temperature change
– diurnal sampling in March, June, Sept. and
Dec. are preferred
Regim Temperatur Tanah ---
Regim
temperatur
tanah
Pergelik
Cryik
Frigid
Isofrigid
Boreal
Mesik
Isomesik
Termik
Isotermik
Hipertermik
Isohipertermi
k
RTTT
RTTMPRTTMD
RTTMP
< 0
0–8
0–8
0–8
<8
8 – 15
8 – 15
15 – 22
15 – 22
> 22
> 22
>5
<5
>5
<5
>5
<5
>5
<5
Renda
h
> cryic
Estimasi temperatur berdasarkan ketinggian
tempat (elevasi)
Di tempat-tempat yang tidak tersedia data
temperatur (stasiun iklim terbatas), maka
temperatur udara dapat diduga berdasarkan
ketinggian tempat (elevasi) dari atas
permukaan laut. Pendugaan tersebut dengan
menggunakan pendekatan rumus dari Braak
(1928) dalam Mohr et al. (1972).
Berdasarkan hasil penelitiannya di Indonesia
temperatur di dataran rendah (pantai) berkisar
antara 25-27ºC, dan rumus yang dapat
digunakan (rumus Braak) adalah sebagai
berikut:
26,3°C - (0,01 x elevasi dalam meter x 0,6°C)
Berdasarkan penelitian Braak tersebut
temperatur tanah pada kedalaman 50 cm di
Indonesia lebih tinggi 3-4,5ºC, sehingga untuk
menduga temperatur tanah pada kedalaman 50
cm, maka rerata temperatur udara ditambah
sekitar 3,5ºC.
Menurut Wambeke et al. (1986) temperatur
tanah lebih tinggi 2,5ºC dari temperatur udara.
Hasil pendugaan temperatur dan ditambah
perbedaan temperatur udara dan temperatur
tanah tersebut digunakan untuk menentukan
rejim temperatur tanah seperti yang ditetapkan
dalam Taksonomi Tanah
(Soil Survey Staff, 1992; 1998).
RADIASI MATAHARI
Permukaan bumi merupakan penyerap utama radiasi
matahari . Oleh sebab itu permukaan bumi merupakan
sumber panas bagi udara di atasnya dan bagi lapisan
tanah di bawahnya.
Pada siang hari suhu permukaan tanah akan lebih
tinggi dibandingkan dengan suhu pada lapisan tanah
yang lebih dalam.
Permukaan tanah menyerap radiasi matahari secara
langsung pada siang hari, setelah itu panas merambat
ke lapisan tanah yang lebih dalam.
Sebaliknya pada malam hari permukaan tanah akan
kehilangan panas terlebih dahulu, akibatnya suhu pada
permukaan tanah akan lebih rendah dibandingkan
dengan suhu pada lapisan yang lebih dalam. Pada
malam hari panas akan merambat dari lapisan yang
lebih dalam menuju permukaan.
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
PERPINDAHAN PANAS
Proses perpindahan panas yang terjadi di
dalam tanah adalah perpindahan panas
secara konduksi.
Proses perpindahan panas ini terjadi
karena adanya gerakan molekul dalam
tanah.
Temperatur adalah suatu pernyataan tentang
kinetik energi molekul benda, adanya suatu beda
suhu di dalam suatu benda umumnya akan
menyebabkan perpindahan energi kinetik oleh
banyaknya tumbukan dari molekul-molekul yang
bergerak dari daerah yang lebih panas ke daerah
sekitarnya yang lebih dingin.
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
TRANSFER PANAS
Proses stedi (steady;) atau proses takstedi
(unsteady) terjadi dalam proses transfer panas.
Bilamana laju aliran panas dalam suatu sistem
tidak berubah dengan waktu (konstan), maka
suhu dititik manapun tidak berubah. Hal ini
yang dikatakan kondisi keadaan-stedi.
Dengan kondisi keadaan-stedi (steady state),
kecepatan fluks-masuk pada titik manapun
dari sistem manapun harus tepat sama dengan
kecepatan fluks-keluar, dan tidak dapat terjadi
perubahan energi-dalam. Aliran panas dalam
suatu sistem takstedi terjadi bila suhu
diberbagai titik dari sistem tersebut berubah
dengan waktu.
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
Dengan adanya perubahan suhu, maka akan terjadi
perubahan energi dalam.
Perubahan kandungan panas dari sebuah permukaan
tanah antara permukaan Z1 = 0 dan beberapa
kedalaman Z2 diberikan oleh :
AS = - (qh2 – qh1) ≈ q h
z
z
Dimana qh positif ke arah bawah
http://www.texasgeology.com/ac_heat_
pumps.html
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM TANAH
MELALUI PENGUKURAN SUHU. Aries Astradhani Subgan. Natural,
Oktober 2006. Vol 5. No.2
KERAPATAN FLUX PANAS
Kerapatan fluks panas tanah positif arah
bawah ketika ΔS = - (qh2 - qh1) positif, maka
lebih banyak panas yang masuk di bagian atas
daripada yang meninggalkan bagian bawah
lapisan tanah sehingga tanah menjadi panas.
Jika ΔS = - (qh2 - qh1) negatif, maka lebih
banyak panas yang keluar daripada yang
masuk ke permukaan sehingga tanah menjadi
dingin.
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
TRANSFER PANAS
Teori transfer panas dalam tanah telah digunakan untuk
menentukan sifat-sifat termal rata-rata dari regim suhu yang
diamati, juga untuk pendugaan perubahan harian dan musiman
suhu tanah. di alam, tanah yang homogen hanya terdapat pada
lapisan-lapisan yang tipis, sehingga suhu tanah umumnya
bukanlah fungsi sinus sederhana.
Amplitude of seasonal
soil temperature
change as a function of
depth below ground
surface.
http://www.builditsolar.
com/Projects/Cooling/
EarthTemperatures.htm
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM TANAH
MELALUI PENGUKURAN SUHU. Aries Astradhani Subgan. Natural,
Oktober 2006. Vol 5. No.2
Grafik Fungsi Fourier Suhu Tanah Bervegetasi
Tiap Kedalaman
36
35
34
Suh 33
u
32
Tana
h 31
0
( C)
30
29
28
27
Z=0 Cm
Z=5 Cm
Z=10 Cm
Z=15 Cm
26
Z=20 Cm
25
Z=25 Cm
24
23
22
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Waktu Pengamatan
Waktu Per 30 Menit
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
Grafik Fungsi Fourier Suhu Tanah Tidak Bervegetasi
Tiap Kedalaman
46
45
44
43
42
41
40
Suh 39
u 38
Tana 37
h 36
0
( C) 35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Waktu Pengamatan
Waktu Per 30 Menit
Z=0 Cm
Z=5 Cm
Z=10 Cm
Z=15 Cm
Z=20 Cm
Z=25 Cm
Sumber: STUDI DIFUSIVITAS TERMAL PADA MEDIUM
TANAH MELALUI PENGUKURAN SUHU. Aries Astradhani
Subgan. Natural, Oktober 2006. Vol 5. No.2
TEMPERATUR TANAH
Temperatur (suhu) adalah salah satu sifat
tanah yang sangat penting secara langsung
mempengaruhi pertumbuhan tanaman dan
juga terhadap kelembapan, aerasi, stuktur,
aktifitas mikroba, dan enzimetik, dekomposisi
serasah atau sisa tanaman dan ketersidian
hara-hara tanaman.
Tenperatur tanah merupakan salah satu faktor
tumbuh tanaman yang penting sebagaimana
halnya air, udara dan unsur hara. Proses
kehidupan bebijian, akar tanaman dan mikroba
tanah secara langsung dipengaruhi oleh
temperatur tanah
Hanafiah, Kemas Ali. 2005. Dasar-dasar Ilmu Tanah. PT. Radja
Grifindo. Persada. Jakarta.
FAKTOR SUHU TANAH
Tentang suhu tanah pengaruhnya penting
sekali pada kondisi tanah itu sendiri dan
pertumbuhan tanaman. Pengukuran dari suhu
tanah biasanya dilakukan pada kedalaman 5
cm, 10 cm, 20 cm, 50 cm, dan 100 cm.
Faktor pengaruh suhu tanah yaitu faktor luar
dan faktor dalam.
Faktor luar yaitu radiasi matahari, awan, curah
hujan, angin, kelembapan udara. Faktor
dalamnya yaitu faktor tanah, struktur tanda,
kadar iar tanah, kandungan bahan organik, dan
warna tanah. Makin tinggi suhu maka semakin
cepat pematangan pada tanaman
Kartasapoetra, dkk. 2005. Teknologi Konservasi Tanah. Rineka
jaya. Jakarta.
FLUKTUASI SUHU TANAH
Suhu tanah beraneka ragam dengan cara khas
pada perhitungan harian dan musiman.
Fluktasi terbesar dipermukaan tanah dan akan
berkurang dengan bertambahnya kedalaman
tanah.
Kelembapan waktu musiman yang jelas
terjadi, karena suhu tanah musiman lambat
bantuk fluktasi suhu pada peralihan suhu
diudara atau dibawah tanah yang lebih besar.
Suhu total untuk semalam tanaman mungkin
terjadi pada tengah hari.
Dibawah 6 inch atau 15 inch terdapat variasi
harian pada suhu tanah
Sosrodorsono. 2006. Variasi Tanah. Rineka Jaya. Bogor.
TEMPERATUR TANAH
Data temperatur tanah dapat dilihat
pada Tabel 4 menunjukkan bahwa suhu
harian pada permukaan tanah sangat
fluktuasi dengan pola mendekati fungsi
sinusoidal.
Fluktuasi temperatur permukaan tanah
dipengaruhi oleh perubahan suhu atmosfir di
atas permukaan tanah.
Temperatur tanah pada pagi hari relatif kecil,
temperatur tanah pada pagi hari di lahan
naungan cenderung lebih tinggi daripada di areal
lahan tanpa naungan.
PENGARUH IRIGASI DAN NAUNGAN TERHADAP PRODUKSI
TANAMAN CABE (Capsicum annum) PADA LAHAN BERPASIR
DI PANTAI GLAGAH, YOGYAKARTA
Ikhwanuddin Mawardi dan Sudaryono. 2008. J. Hidrosfir Indonesia Vol. 3(1) :
41 -49
SUHU TANAH - KEDALAMAN
Pada variasi kedalaman yaitu
permukaan tanah, kedalaman 10 cm, 20
cm dan 30 cm, untuk temperatur tanah
dalam naungan memiliki temperatur yang
tertinggi, sedangkan kedalaman 10 cm
mempunyai temperatur tanah terendah.
Hal ini disebabkan pada pagi hari
permukaan tanah telah menerima
pancaran radiasi matahari, tetapi transfer
panas belum mencapai kedalaman 10
cm.
Temperatur tanah pada kedalaman 30 cm
lebih tinggi dibandingkan kedalaman 10
cm dan 20 cm, karena masih menyimpan
sebagian energi radiasi matahari yang
diterima sehari sebelumnya.
SUHU TANAH – SIANG AHRI
Temperatur tanah pada siang hari, jika
dilihat pada tabel tersebut dapat dilihat
bahwa temperatur tanah pada sing hari
lebih panas daripada temperatur tanah
pada pagi hari.
Hal ini dapat terjadi karena pada siang
hari radiasi yang diterima oleh
permukaan tanah lebih besar.
Temperatur tanah pada siang hari di
areal lahan dengan memakai naungan
lebih tinggi daripada lahan yang tidak
memakai naungan.
SUHU TANAH - LAPISAN TANAH
Berdasarkan variasi kedalaman, maka
permukaan tanah mempunyai temperatur
tanah tertinggi, sedangkan kedalaman 30
cm mempunyai temperatur tanah
terendah.
Jadi pada siang hari temperatur
permukaan tanah akan lebih tinggi jika
dibandingkan temperatur pada lapisan
tanah yang lebih dalam.
Hal ini disebabkan karena permukaan
tanah menyerap radiasi matahari secara
langsung, baru kemudian panas
dirambatkan ke lapisan tanah yang lebih
dalam secara konduksi.
SUHU TANAH - KEDALAMAN
Temperatur tanah pada sore hari akan
lebih kecil dibandingkan dengan
temperatur tanah pada pagi dan siang
hari. Temperatur tanah dalam naungan
lebih tinggi daripada di areal lahan tanpa
naungan.
Berdasarkan variasi kedalaman,
pada kedalaman 10 cm mempunyai
temperatur tanah tertinggi sedangkan
kedalaman 30 cm memiliki temperatur
tanah terendah.
Tingginya temperatur
tanah pada kedalaman 10 cm dapat
disebabkan oleh akumulasi transfer panas
dari permukaan atau tingginya aktivitas
mikroorganisme dalam merombak bahan
organik pada lapisan tersebut.
FLUKTUASI SUHU TANAH
Bila dilihat dari hasil pengamatan
selama 3 bulan, baik itu pagi, siang dan
sore hari terlihat temperatur tanah
berfluktuasi, dan cenderung lebih stabil
seiring dengan bertmbahnya umur
tanaman.
Fluktuasi temperatur pada
permukaan tanah lebih besar daripada
kedalaman 10 cm, 20 cm dan 30 cm. Hal
ini tidak terlepas dari pengaruh intensitas
radiasi matahari yang diterima oleh
permukaan tanah.
Jadi intensitas radiasi matahari yang berfluktuasi
akan menyebabkan temperatur tanah juga
berfluktuasi.
Alison L. Spongberg
Kevin P. Czajkowski
Jason Witter
University of Toledo
Soil temperatures over three days at different depths.
Sumber:
http://www.learner.org/jnorth/tm/tulips/SoilTempBack.html.....
diunduh 12/2/2012
Our goal at UT:
Study temporal and spatial
relationships between soil temperature
and various factors
• Diurnal and seasonal variation
• Modify current protocol
• Other latitudes 2-5 years
Study global energy flux.
We need soil temperature variations
throughout the year, without the
confounding influence of diurnal
variations.
Could we arrive at an algorithm to
determine soil temperature at depth
from the shallow measurements?
15 Field Sites
2-4 week intervals since 12/2002.
Collected within 3 hours of Solar Noon.
Each site same time every collection when
possible
Collected to 1 meter depth at 10cm
intervals
Temperature (Air and surface
included)
Wind Speed (1 min average)
Moisture (surface also)
pH
Soil texture
Land Cover, Shade Conditions
Cloud Cover
Snow/Ice
Water Table
Automated Data Collection
Temperature (10, 20, 30, 40, 50,
60, 80, 100cm) 4 channel HOBO
External Dataloggers
4 sites: 2 clay soils (Lake Erie
Center), 2 sandy soils (Stranahan
Arboretum)
Each has 1 open site and 1
forested site. Collects every 2.5
minutes since September 2003
Soil texture and pH
The R. A. Stranahan Arboretum, University of Toledo
47 acre property- ponds, forest,
prairie, wetland, and open areas.
Sandy Soils (Bixler, Lamsom) Sisson
Loam dunes formed from paleo-lake
shorelines.
Yellow Dots Represent
Sites. 13, 9, and LEC are
also data-logger sites.
Local Climate/Ground Cover
Left: cyclic nature of
yearly temp and
turnover dates is
generalized here.
Below left: annual
change with depth.
Below right:
relationship between
soil moisture and
temperature decreases
with depth.
Temperature Profile for Several Sites showing spatial
variation of temperature during two collection dates in the
coldest and warmest months for surface temperature in 2003.
Soil Texture -
Particle Size Analysis
Soil Texture
Soil moisture at shallower
depths
Water flow though the soil
Cloud cover
Land cover
Suhu Tanah
• Relation of Soil & Air Temp
– Net heat absorbed by the Earth =
heat lost in form of longwave
radiation
– Photoperiod – affected by
latitude
– Soil temp can change by soil
depth & time of day
• Takes significant air temp changes
to change soil temp deeper than 12”
(& more than just daily range)
Suhu Tanah
• Avg. summer & winter soil temps @
3’ rarely differ by more than 9° F.
• Factors Affecting Soil Temp
– How much heat reaches the soil
surface
•
•
•
•
•
Tutupan muka tanah
Mulsa plastik
Sudut datang radiasi matahari
Arah Muka Lereng
Tanah
Suhu
Tanah
– What happens to the heat in the
soil (dissipation)
• Amount of heat needed to change soil
temp = heat capacity
– Greatly affected by soil water content
» How?
– Thermal conductivity – increases
w/ soil-water content increasing,
decreases as air-filled pores
increase
• Moist soils resist temp change, but
conduct heat readily
• Dry soils change temp faster, but
conduct heat poorly
– What does this mean for the soil,
which is better?
Suhu Tanah
• Living w/ Existing Temps
– Maximizing seed germination &
growth
• Wheat – 40 to 50° F
• Corn – 50 to 85° F
– When using anhydrous
• Apply when soil temp @ 4” is 50° F
or less
– Mereduksi kehilangan N
– Freeze/thaw
• May cause heaving – resulting in
death of shallow rooted crops
Suhu tanah
– Responsible for bringing
stones to the surface in fields
• Modifying Temp Effects
– If you have crops that are
feasible/profitable to do so
– Clear plastic surface covers
• Increases soil temp faster
– Clear plastic mulches
• Can speed growth & maturity of
sweet corn & strawberries
CIRI THERMAL TANAH
The thermal properties of soil are a
component of soil physics that has found
important uses in engineering, climatology
and agriculture.
These properties influence how energy is
partitioned in the soil profile. While related to
soil temperature, it is more accurately
associated with the transfer of heat throughout
the soil, by radiation, conduction and
convection.
The main soil thermal properties are:
Volumetric heat capacity, SI Units: J.m-3∙K-1
Thermal conductivity, SI Units: W.m-1∙K-1
Thermal diffusivity , SI Units: m2∙s-1
. http://en.wikipedia.org/wiki/Soil_thermal_properties
….. Diunduh 4/2/2012
SUHU TANAH dipengartuhi oleh:
Latitude; season
net radiation at the surface
soil texture ; moisture content
ground cover
surface weather conditions
. http://en.wikipedia.org/wiki/Soil_thermal_properties
….. Diunduh 4/2/2012
CIRI-CIRI THERMAL TANAH
So, in order to determine the skin temperature
of the soil, it is important to understand how
heat is transferred upward and and downward
through the soil. The important heat transfer
mechanism in this problem is conduction.
Then, the ground heat flux at any depth in the
soil can be given as:
where kg is the thermal diffusivity of the soil.
http://apollo.lsc.vsc.edu/classes/met455/notes/section6
/2.html .... diunduh 5/2/2012
Using the Second Law of Thermodynamics, show that
a prognostic equation for the soil temperature can be
given by:
(2)
where Cg is the soil heat capacity (Cg = soil density, r,
times the soil specific heat, c)
combining (2) with (1) yields:
(3)
where vg = kg/Cg = soil thermal diffusivity.
Given proper boundary conditions, (3) can be solved to find the
soil temperature at different levels as a function of time. With
appropriate boundary conditions, solutions to (3) show that soil
temperature decreases exponentially with depth and that the
phase of the temperature changes with depth as well, consistent
with the figures shown above.
http://apollo.lsc.vsc.edu/classes/met455/notes/section6
/2.html .... diunduh 5/2/2012
Typical values of the mass density, specific heat,
thermal conductivity and thermal diffusivity for
different materials
SPECIFIC
THERMAL
MASS
THERMAL
MATE CONDITI
HEAT (c) (J CONDUCTIVI
DENSITY (r)
DIFFUSIVITY
RIAL
ON
kg-1 K-1 x TY (kg) (W m-3
3
(kg m x 10 )
(vg) (m2 s-1 x10-6)
2 K-1)
103)
Air
20 Deg
C, Still
0.0012
1.01
0.025
20.5
Water
20 Deg
C, Still
1.00
4.19
0.57
0.14
Ice
0 Deg C,
Pure
0.92
2.10
2.24
1.16
Snow
Fresh
0.10
2.09
0.08
0.38
Snow
Old
0.48
2.09
0.42
0.05
Sandy
Soil
Fresh
1.60
0.80
0.30
0.24
Clay
Soil
Dry
1.60
0.89
0.25
0.18
Peat
Soil
Dry
0.30
1.92
0.06
0.10
Rock
Solid
2.70
0.75
2.90
1.43
http://apollo.lsc.vsc.edu/classes/met455/notes/section6/2.html .....
Diunduh 6/2/2012
FLUKTUASI SUHU TANAH
Soil temperature variations decrease
exponentially with depth. only small
fluctuations are observed at depths of about 1
meter. much smaller fluctuations are observed
at depths of 10 meters.
http://apollo.lsc.vsc.edu/classes/met455/notes/section6/2.html .....
Diunduh 6/2/2012
KAPASITAS PANAS VOLUMETRIK
Volumetric heat capacity (VHC), also
termed volume-specific heat capacity,
describes the ability of a given volume of a
substance to store internal energy while
undergoing a given temperature change, but
without undergoing a phase change.
It is different from specific heat capacity in
that the VHC depends on the volume of the
material, while the specific heat is based on
the mass of the material (or occasionally the
molar quantity of the material).
If given a specific heat value of a substance,
one can convert it to the VHC by multiplying
the specific heat by the density of the
substance.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
KAPASITAS PANAS
Dulong and Petit predicted in 1818 that the product of
solid substance density and specific heat capacity
(ρcp) would be constant for all solids. This amounted
to a prediction that volumetric heat capacity in solids
would be constant.
This quantity was proportional to the heat capacity per
atomic weight (or per molar mass), which suggested
that it is the heat capacity per atom (not per unit of
volume) which is closest to being a constant in solids.
Eventually (see the discussion in heat capacity) it has
become clear that heat capacities per particle for all
substances in all states are the same, to within a factor
of two, so long as temperatures are not in the
cryogenic range.
For very cold temperatures, heat capacities fall
drastically and eventually approach zero as
temperature approaches zero.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
KAPASITAS PANAS VOLUMETRIK
.
The heat capacity on a volumetric basis in solid
materials at room temperatures and above varies more
widely, from about 1.2 to 4.5 MJ/m³K, but this is
mostly due to differences in the physical size of
atoms.
If all atoms were the same size, molar and volumetric
heat capacity would differ by a single constant
reflecting ratios of the atomic-molar-volume of
materials (their atomic density), plus an additional
number between 1 and 2 which reflects degrees of
freedom for the atoms compositing the substance at
various temperatures.
For liquids, the volumetric heat capacity is narrower:
in the range 1.3 to 1.9 MJ/M³k.
This reflects the modest loss of degrees of freedom for
particles in liquids as compared with solids.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
KAPASITAS PANAS VOLUMETRIK
Since the bulk density of a solid chemical element is
strongly related to its molar mass (usually about 3 R per
mole, as noted above), there exists noticeable inverse
correlation between a solid’s density and its specific heat
capacity on a per-mass basis. This is due to a very
approximate tendency of atoms of most elements to be
about the same size, despite much wider variations in
density and atomic weight. These two factors (constancy of
atomic volume and constancy of mole-specific heat
capacity) result in a good correlation between the volume
of any given solid chemical element and its total heat
capacity. Another way of stating this, is that the volumespecific heat capacity (volumetric heat capacity) of solid
elements is roughly a constant.
The molar volume of solid elements is very roughly
constant, and (even more reliably) so also is the molar heat
capacity for most solid substances. These two factors
determine the volumetric heat capacity, which as a bulk
property may be striking in consistency.
For example, the element uranium is a metal which has a
density almost 36 times that of the metal lithium, but
uranium's volumetric heat capacity is only about 1.2 times
larger than lithium's.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
.
KONDUKTIVITAS THERMAL
Thermal conductivity, k, is the property of a
material's ability to conduct heat. It appears
primarily in Fourier's Law for heat
conduction.
Heat transfer across materials of high thermal
conductivity occurs at a higher rate than
across materials of low thermal conductivity.
Correspondingly materials of high thermal
conductivity are widely used in heat sink
applications and materials of low thermal
conductivity are used as thermal insulation.
Thermal conductivity of materials is
temperature dependent. The reciprocal of
thermal conductivity is thermal resistivity.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
SUHU TANAH - MUSIMAN
Soil temperature varies from month to month as a function of
incident solar radiation, rainfall, seasonal swings in overlying air
temperature, local vegetation cover, type of soil, and depth in the
earth.
Due to the much higher heat capacity of soil relative to air and
the thermal insulation provided by vegetation and surface soil
layers, seasonal changes in soil temperature deep in the ground
are much less than and lag significantly behind seasonal changes
in overlying air temperature.
Thus in spring, the soil naturally warms more slowly and to a
lesser extent than the air, and by summer, it has become cooler
than the overlying air and is a natural sink for removing heat
from a building. Likewise in autumn, the soil cools more slowly
and to a lesser extent than the air, and by winter it is warmer than
the overlying air and a natural source for adding heat to a
building.
At soil depths greater than 30 feet below the surface, the soil
temperature is relatively constant, and corresponds roughly to the
water temperature measured in groundwater wells 30 to 50 feet
deep. This is referred to as the “mean earth temperature.”
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
SUHU TANAH – FLUKTUASI MUSIMAN
The amplitude of seasonal changes in soil
temperature on either side of the mean earth
temperature depends on the type of soil and
depth below the ground surface.
In Virginia the amplitude of soil temperature
change at the ground surface is typically in the
range of 20-25ºF, depending on the extent and
type of vegetation cover.
At depths greater than about 30 feet below the
surface, however, the soil temperature remains
relatively constant throughout the year, as
shown in Figure 3, below.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity … diunduh
5/2/2012
SUHU TANAH – KEDALAMAN PROFIL.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh
5/2/2012
SUHU TANAH - VARIASI HORISONTAL
Vertical closed-loop earth heat exchangers are
installed in boreholes 200 to 300 feet deep, where
seasonal changes in soil temperature are completely
damped out. Well-based open-loop systems also
extend to this depth or deeper. These ground loop
configurations are thus exposed to a constant yearround temperature.
On the other hand, horizontal-loop, spiral-loop, and
horizontal direct-expansion (DX) loops are installed in
trenches that usually are less than 10 feet deep. For
these types of ground loops, it is important to
accurately know the expected seasonal changes in the
surrounding soil temperature.
The extra cost of installing such systems in deeper
trenches may be outweighed by the gain in thermal
performance, since deeper soils have less pronounced
seasonal temperature changes and are thus closer to
room temperature, which reduces the work load of the
heat pump units.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
SUHU TANAH – KEDALAMAN
Deeper soils not only experience less extreme seasonal
variations in temperature, but the changes that do occur
lag farther behind those of shallower soils. This shifts the
soil temperature profile later in the year, such that it more
closely matches the demand for heating and cooling.
The maximum soil temperature occurs in late August (when
cooling demand is high) at a depth of 5 feet below the
ground surface, but occurs in late October (after the
heating season has begun) at a depth of 12 feet below the
surface.
Thus a deeper ground loop installation would lower the
annual operating cost for electrical energy to run the heat
pumps, and over the life of a GHP system, these
accumulated savings may more than offset the higher
capital cost of burying the ground loop more deeply.
In order to determine the optimal depth of burial, it is
important to accurately know how the seasonal change in
soil temperature varies with depth, which is mainly
determined by the soil's thermal properties.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
. Seasonal soil temperature change as a function of
depth below ground surface for an average moist soil.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh
5/2/2012
CIRI-CIRI THERMAL TANAH
Heat capacity (also known as specific heat) indicates
the ability of a substance to store heat energy; the
greater its heat capacity, the more heat it can gain (or
lose) per unit rise (or fall) in temperature.
The heat capacity of dry soil is about 0.20 BTU per
pound per ºF of temperature change, which is only
one-fifth the heat capacity of water. Therefore, moist
or saturated soils have greater heat capacities,
typically in the range of 0.23 to 0.25 BTU/lb/ºF.
The light dry soils experience greater seasonal
temperature swings at a given depth than wet soils.
This is because their lower heat capacity causes their
temperature to rise or fall more than wet soils for a
given amount of heat energy gained in the spring or
lost in the fall.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh
5/2/2012
KONDUKTIVITAS THERMAL
(KT) Thermal conductivity is another soil property that
must be known in order to design a closed-loop or direct
expansion GHP system. This indicates the rate at which
heat will be transferred between the ground loop and the
surrounding soil for a given temperature gradient.
The thermal conductivity of the soil and rock is the critical
value that determines the length of pipe required, which in
turn affects the installation cost as well as the energy
requirements for pumping working fluid through the ground
loop.
KT - TANAH BERAGAM DENGAN TEKSTURNYA.
Heat transfer capability tends to increase as soil texture
becomes increasingly fine, with loam mixtures having an
intermediate value between sand and clay. As also shown
in this figure, the thermal conductivity of any soil greatly
improves if the soil is saturated with water. This effect is
much greater for sandy soils than for clay or silt, since
coarse soils are more porous and therefore hold more
water when wet.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh
5/2/2012
Konduktivitas thermal berbgaai tipe
tekstur tanah.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
KONDUKTIVITAS PANAS
The soil thermal conductivity has a significant impact on the size
of the earth-coupled heat exchanger. Thus in sandy soils for
example the required length of the ground loop could be as low
as 200 feet per system ton if the soil is saturated with water, or as
high as 300 feet per ton if the soil is dry.
Soil thermal conductivity is of even greater importance to DX
systems and designers might consider the deployment of a
“soaker hose” for horizontal DX ground loops in dry areas or if
the project site is higher than the sounding terrain.
The maps presented in the next section below enable rough
estimates of soil properties for regional screening purposes, but
any sort of detailed feasbility assessment or design study should
engage a contractor for in-situ soil thermal conductivity testing.
The range in ground loop lengths over the typcial range of soil
thermal conductivities is 200 to 300 feet per system ton, which
translates into a 30-50% difference in required land area, and a
10-20% difference in total system capital cost.
In-situ conductivity testing minimizes the uncertainty in
estimating this key thermal property and avoids undersizing or
oversizing the ground loop.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
Thermal conductivity influence on number of
boreholes and total length of the earth-coupled heat
exchanger per 10 tons of load for a vertical closedloop GHP system.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
SUHU TANAH
Amplitude: Amplitude is a parameter characterizing the annual
variation of soil temperature around an average value. If the
variation in temperature within a day is averaged out over many
years, the annual amplitude is one-half the difference between
this annual averaged maximum and annual averaged minimum
temperatures within a year.
Damping depth: Damping depth is a constant characterizing the
decrease in amplitude with an increase in distance from the soil
surface. It is defined as (2Dh/w)1/2, where D h is the thermal
diffusivity and w is the frequency of a temperature fluctuation.
For annual fluctuation w =2 p /365 d-1.
Thermal diffusivity: Thermal diffusivity is the change in
temperature produced in a unit volume by the quantity of heat
flowing through the volume in unit time under a unit temperature
gradient. It can be calculated from thermal conductivity and
volumetric heat capacity.
Time lag: Time lag is the number of days from an arbitrary
starting date to the occurrence of the minimum temperature in a
year.
. http://www.geo4va.vt.edu/A1/A1.htm …. Diunduh 5/2/2012
SUHU TANAH - WAKTU DAN
KEDALAMAN
Soil temperature fluctuates annually and daily
affected mainly by variations in air temperature
and solar radiation.
The annual variation of daily average soil
temperature at different depths can be estimated
using a sinusoidal function (Hillel, 1982;
Marshall and Holmes, 1988; Wu and Nofziger,
1999).
This program estimates daily soil temperatures
and displays these values as functions of time or
depth for user defined input parameters.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
MODEL VARIASI SUHU TANAH
The annual variation of daily average soil temperature
at different depths is described with the
following sinusoidal function ( Hillel, 1982):
where T(z,t) is the soil temperature at time t (d) and
depth z (m), T a is the average soil temperature (oC),
A0 is the annual amplitude of the surface soil
temperature (oC), d is the damping depth (m) of
annual fluctuation and t0 is the time lag (days) from
an arbitrary starting date (taken as January 1 in this
software) to the occurrence of the minimum
temperature in a year.
The damping depth is given by d = (2D h/w )1/2,
where Dh is the thermal diffusivity and w = 2
p /365 d-1 .
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
MODEL SINUS VARIASI SUHU TANAH
Assumptions and Simplifications
The sinusoidal temperature model was derived by
solving the following partial differential
equation ( Hillel, 1982 ; Marshall and Holmes, 1988):
where T(z,t) is the soil temperature at time t and depth
z and Dh is the thermal diffusivity.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
VARIASI SUHU TANAH
The following assumptions are employed in the
derivation of the temperature model:
1. A sinusoidal temperature variation at the soil
surface z = 0. That is
where Ta is the average soil temperature, A0 is the
amplitude of the annual temperature function, t0 a
time lag from an arbitrary starting date (selected as
January 1 in this software) to the occurrence of the
minimum temperature in a year.
2. At infinite depth, the soil temperature is constant
and is equal to the average soil
temperature.
3. The thermal diffusivity is constant throughout the
soil profile and throughout the year.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
Measured mean and predicted soil temperatures at
four depths based on measured soil
surface temperatures.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
Suhu tanah pada berbagai kedalaman:
Diprediksi berdasarkan suhu udara.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
Konduktivitas dan difusivitas thermal tanah:
Dipengaruhi kadar air, kadaungan liat, dan bobot isi
tanah.
http://soilphysics.okstate.edu/software/SoilTemperature/documen
t.pdf …. DIUNDUH 5/2/2012
Volumetric heat capacity for three bulk densities for soils whose thermal
conductivity and diffusivity.
http://www.usyd.edu.au/agric/web04/Temperature%20Waves_final.htm
SUHU TANAH - PENANAMAN
Whether you’re planting seeds or targeting weeds, it’s important to check your
soil temperature before beginning.
Even the best-planned garden project can fall flat if temperatures are not
appropriate for the occasion! For example, did you know that you should:
Plant spring bulbs when the soil temperature drops below 60° F.
Apply crabgrass control in spring, when soil temperatures reach 55° F for 4-5
days in a row.
Plant cool-season grass seed once soil temperatures are in the 50s F.
Give your new shrubs time to grow roots before soil temperatures fall below 40°
F.
Be very careful when starting vegetable seeds, since germination temperature is
vital to the seeds’ success and every vegetable is different.
Soil temperature plays an important role in soil chemical reactions and biological
interactions, particularly nutrient and fertilizer transformations, solute transport, gas
exchange and the transformation and transport of contaminants (Buchan 2001).
Soil temperature varies in response to exchange processes that take place primarily
through the soil surface. These effects are propagated into the soil profile by transport
processes and are influenced by such things as the specific heat capacity, thermal
conductivity and thermal diffusivity.
Soil temperature can vary greatly throughout the day with increasing and decreasing
solar radiation. Soil temperatures also vary greatly with depth from the surface, as
well as with differences in soil cover (mulch) and soil water content. The thermal
properties of a soil have been found to be indicative of the soil water content. Water is
a better thermal conductor than air. The thermal conductivity of soil increases with
increasing water contents (Fredlund, 1992).
Buchan, G.D., (2001) Soil Temperature Regime, in Smith, K.A., and Mullins, C.E. (Eds). Soil and
Environmental Analysis: Physical Methods 2nd Ed. 2001. Marcel Dekker. pp, 539-594.
Fredlund, D.G. (1992). Background, Theory, and Research Related to the Use of Thermal
Conductivity Sensors for Matric Suction Measurement. Soil Science Society of America. Advances
in Measurement of Soil Physical Properties: Bringing Theory into Practice, 249-261.
http://www.usyd.edu.au/agric/web04/Temperature%20Waves_final.htm.
http://www.dannylipford.com/how-to-measure-soil-temperature-for-planting/
TERMOMETER TANAH
You can purchase a simple soil thermometer at your local garden center
for just a few dollars.
The most economical ones are glass bulb thermometers with a strong
metal point. However, any thermometer will do, as long as it measures
temperatures down to freezing (medical thermometers usually don’t go
low enough).
Influence of soil temperature on nitrification.
Ammonium sulfate nitrification after 24 days. Soils held at either constant
temperature (80, 60, or 40°F) for 24 days, or the temperature varied (between 80,
60, and 40°F sequences) by 8- or 12-day intervals over the 24 days.
Adapted from Chandra, P. 1962. Note on the effect of shifting temperatures on
nitrification in a loam soil. Can. J. Soil Sci. 42:314-315.
Temperature Sequence
% Nitrification
Continuous at 80°F for 24 days
100
12 Days at 80°F-12 days at 40°F
96
8 Days at 80°F-8 days at 60°F-8 days
at 40°F
74
12 Days at 40°F-12 days at 80°F
62
Continuous at 60°F for 24 days
59
8 Days at 60°F-8 days at 80°F-8 days
at 40°F
8 Days at 40°F-8 days at 60°F-8 days
at 80°F
Continuous at 40°F for 24 days
56
45
29
http://www.ipm.iastate.edu/ipm/icm/2001/10-22-2001/why50.html … diuduh 15/2/2012
BAGAIMANA MENGUKUR SUHU TANAH?.
Measure the Right Depth: If you are planting seeds or
new plants, take your measurement at the recommended
planting depth. If you’re measuring for a mixed garden,
check at least 5-6 inches deep.
Make a Pilot Hole: Use a screwdriver to make a pilot hole
so that you don’t break your thermometer by pushing it into
hard soil.
Follow Directions: Refer to your thermometer package for
specific instructions. With most glass bulb thermometers,
make sure it is firmly touching the soil, and allow a few
minutes for the temperature to register.
Provide Shade: If the sun is bright, shade the
thermometer with your hand to keep the reading accurate.
Multiple Measurements: Take a reading in the morning
and late afternoon, then average the two numbers. If you’re
seeding a lawn, take readings on all four sides of your
house, since some areas warm more quickly than others.
Check Reading: To double-check, refer to these handy
Soil Temperature Maps from Greencast for a comparison
with your soil reading.
SUHU TANAH – PERKECAMBAHAN BENIH
The soil temperature for planting vegetables should be:
40° F or warmer: Lettuce, kale, peas, spinach.
50° F or warmer: Onions, leeks, turnips, Swiss chard.
60° F or warmer: Broccoli, cabbage, cauliflower, carrots, beans, beets.
70° F or warmer: Tomatoes, squash, corn, cucumbers, melons, peppers.
The seed germination temperature is often much warmer than the plant’s growing
temperature. Once established, many veggies can handle much cooler air
temperatures as long as the soil is warm enough.
To get a head start on spring planting, plant seeds indoors or use plastic row covers
to warm the soil more quickly.
Temperature has a large influence on rate of seed water uptake, speed of germination, and rate of plant
emergence. As temperature increases, both the rate of water uptake and speed of germination increase and
time to emergence decreases for winter wheat
The effect of soil temperature on speed of germination and emergence of Norstar winter wheat (from
Lafond and Fowler, 1989).
http://www.usask.ca/agriculture/plantsci/winter_cereals/Winter_wheat/CHAPT11/cvchpt11.php
. Soil temperature and vegetable seed germination
Vegetable
Minimum temp.
(degrees F)
Optimum temp.
(degrees F)
Beans
60
60-85
Cabbage
40
45-95
Carrots
40
45-85
Corn
50
60-95
Cucumbers
60
60-95
Lettuce
35
40-80
Muskmelons
60
75-95
Okra
60
70-95
Onions
35
50-95
Parsley
40
50-85
Peas
40
40-75
Peppers
60
65-95
Pumpkins
60
70-90
Spinach
35
45-75
Squash
60
70-95
Swiss chard
40
50-85
Tomatoes
50
70-95
Turnips
40
60-105
Watermelons
60
70-95
.http://www.waldeneffect.org/blog/Soil_temperature_and_vegetable_see
d_germination/
Diunduh 5/2/2012
SUHU TANAH - TANAMAN
The temperature of a soil is important as it affects how fast plants can grow. Soil temperature
also affects how quickly plants take up water and nutrients. Clay soils are cold, wet soils.
Germination and seedling growth is usually slow.
Because sandy soils don't contain much water but lots of air, they warm up quickly. They are
useful for growing early crops.
Soil temperature affects the speed of chemical reactions. Warm temperatures speed up
reactions and colder ones slow them down. Soil temperature affects the breakdown of parent
material and how fast micro-organisms work. Both are important in adding and returning
nutrients to the soil.
Soil temperature is influenced by the climate of the area and the season of the year.
http://www.correspondence.school.nz/departments/horticulture/ht106_p7.html. .... Diunduh
5/2/2012
Effect of soil temperature and water potential on emergence time of Norstar winter
wheat (from Lafond and Fowler, 1989).
http://www.usask.ca/agriculture/plantsci/winter_cereals/Winter_wheat/CHAPT11/cvchpt11.p
hp
SUHU TANAH - POSISI LERENG
The slope of the land and the direction that it faces
directly affects the temperature of a soil. Sun will fall
on north-facing land during the day in both summer
and winter.
http://www.correspondence.school.nz/departments/horticulture/ht
106_p7.html
Diunduh 5/2/2012
SUHU TANAH – KEDALAMAN TANAH
The deeper you go down in a soil profile the less the
soil temperature will fluctuate
Soil is a good
insulator. It can take a
while for the soil at
the bottom of a profile
to heat up, but it will
also take a longer time
for it to lose the heat
that is stored there.
http://www.correspondence.school.nz/departments/horticulture/ht
106_p7.html
Diunduh 5/2/2012
SUHU TANAH DAN AKTIVITAS BIOLOGIS
TANAH
Soil temperature affects the speed of plant growth and soil processes.
Soil temperature is influenced by: climate, season, aspect, water levels, soil colour,
plant cover and soil depth.
The temperature in a soil will determine the speed of chemical and biological activity.
Clay soils take a long time to warm up but are also slower to cool down. The
temperature in a sandy soil can change rapidly. Wet soils also take longer to warm
up.
http://www.correspondence.school.nz/departments/horticulture/ht106_p7.html
Diunduh 5/2/2012
Amplitude of seasonal soil temperature change as a function of depth below ground surface.
http://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm diunduh 15/2/2012
SUHU-TANAH OPTIMUM BAGI TANAMAN
Corn requires a soil temperature of 50° F to germinate
and grow and soybeans require a soil temperature of
54° F.
Temperatures below the optimum will cause seeds to sit dormant
and become more vulnerable to diseases, insects, and animal
predators.
Crops should be planted when soil temperatures are optimal and
within the target dates for the region.
Keep in mind these dates are based on the average year and the use
of short or long relative maturity corn products will affect these
target dates.
Planting into cold and/or wet soils can lead to numerous problems.
Aqua ammonia incubated in soil at controlled temperature.
http://www.ipm.iastate.edu/ipm/icm/2001/10-22-2001/why50.html
http://munsonhybrids.com/tidbits/Plant%20Corn%20and%20Soybean%20By%20Soil%20Te
mperature%20and%20Conditions%20Not%20According%20To%20The%20Calendar%20%20IA.pdf ….. Diunduh 5/2/2012
SUHU TANAH DAN PERTUMBUHAN
BIBIT
Soil temperature is more important than air temperature
when planting seeds or seedlings. You can have in the
spring a warm spell of temps in the 70’s while the soil
temp is still in the 40’s. Every vegetable has a preferred
soil temp for seeds or transplants. A soil thermometer is
essential for determining the proper planting time.
Planting too early, before the soil has had time to warm
up, can lead to seed rot, slowed germination, poor
growth and disease.
Use the following guide for minimum soil temperatures
for seeds and transplants:
60o F - tomatoes, cucumbers, snap beans
65o F - sweet corn, lima beans, mustard greens
70o F - peppers, watermelons, squash, southern peas
75o F - okra, cantaloupe, sweet potatoes
http://yardener.com/YardenersPlantHelper/FoodGardening/BasicsofVegetableGar
dening/SoilBuildingandManagementintheVegetableGarden/SoilTemperatureIsIm
portant
Diunduh 5/2/2012
Soil Temperature Germination Ranges for Select Vegetables
TEMP (°
F)
PLANT
35–75
spinach (optimum 68)
35–80
lettuce and most salad greens (at more than 80,
germination rate drops 50%)
40–75
peas (optimum 75)
45–85
cabbage, kale, broccoli, collards (germinate well at 85,
seedlings prefer 45–65)
45–95
radishes (optimum 85)
50–85
onions (optimum 75)
50–85
beets, Swiss chard (optimum 85)
60–85
beans, snap and dry (optimum 80)
60–95
corn (optimum 95)
60–95
peppers (optimum 85)
65–100
cucumbers, melons, squash (optimum 80–95)
65–82
tomatoes (optimum 80)
70–85
beans, lima (optimum 85)
From: Market News, March 1995.
http://yardener.com/YardenersPlantHelper/FoodGardening/BasicsofVegetableGardening/Soil
BuildingandManagementintheVegetableGarden/SoilTemperatureIsImportant
Diuinduh 5/2/2012
Daftar Pustaka
deVries, D. A., 1963. Thermal Properties of Soils. In W.R.
van Wijk (ed.) Physics of Plant Environment. NorthHolland Publishing Company, Amsterdam.
de Vries, D. A. 1975. Heat Transfer in Soils. In D.A. de
Vries and N.H. Afgan (ed.) Heat and Mass Transfer in the
Biosphere. Pp.5-28. Scripta Book Co., Washington, DC.
Farouki, O.T. 1986. Thermal Properties of Soils. Series on
rock and soil mechanics. Vol. 11. Trans Tech Publ.,
Clausthal-Zellerfeld, Germany.
Hillel, D. 1982. Introduction to soil physics. Academic
Press, San Diego, CA.
Marshall, T. J. and J. W. Holmes 1988. Soil Physics. 2nd
ed. Cambridge Univ. Press, New York.
Wu, J. and D. L. Nofziger 1999. Incorporating temperature
effects on pesticide degradation into a management model.
J. Environ. Qual. 28:92-100.