prinsip management kesuburan tanah

PRINSIP-PRINSIP
MANAJEMEN
KESUBURAN TANAH.
Bahan Kajian MK. Manajemen Kesuburan Tanah
Diarikan soemarno - jursntnhfpub - Sept 2013
PRINSIP-PRINSIP
MANAJEMEN KESUBURAN TANAH
1. Tujuan Program MST.
2. Concepts of large scale, intermediate and
small scale “precision” farming.
3. Soil and plant sampling, testing, and
interpretation.
4. Kesuburan tanah dan Manajemen pupuk
5. Aplikasi, efisiensi dan manfaat pupuk.
SASARAN MANAJEMEN KESUBURAN
TANAH
1. Meningkatkan hasil tanaman (pangan dunia)
2. Mereduksi biaya per satuan hasil
3. Kualitas produk (not always a factor - fast
growing wood is lower quality than slowgrowing wood)
4. Mereduksi gangguan penyakit (can go the
other way by making tissues protein-rich and
juicy for bugs)
5. Mencegah pencemaran lingkungan (new
since the 60's - never used to be considered)
6. Memperbaiki kesehatan dan estetika
lingkungan
7. Memperbaiki habitat liar (hunting permits)
TUJUAN PRODUSEN
1. Cut the unit cost of production by producing
the largest possible crop.
2. Match the crop needs with available nutrient
supply.
3. Nitrates, phosphates, and pesticides – the old
way
4. Typical crop uptake values (archaic units lb/acre - multiply by 1.12 to get kg/ha; also
note that P as P2O5 and K as K2O)
Aplikasi pupuk yang bijaksana dapat
melindungi lingkungan.
1. Pupuk memperbaiki pertumbuhan tanaman
2. Semakin banyak tanaman, semakin banyak
CO2 yang diserap (diambil) dari udara
atmosfir
3. Semakin banyak vegetasi penutup muka
lahan , semakin sedikit erosi dan
pencemaran perairan
SEKALA PENGELOLAAN LAHAN
Large-scale: Treating the entire field as one
management unit.
1. SEDERHANA DAN TEKNOLOGI TEPATGUNA
2. Presisi operaisonal relatif rendah.
3. Tidak memperhitungkan variabilitas lahan dan
kandungan haranya.
4. Memerlukan sedikit instrumentasi dan latihan
teknologi
5. Produksi tidak merata dan potensi
pencemartan lingkungan
SEKALA MEDIUM.
Medium-scale: Sub-dividing the field into two or
more management units requiring different
applications of fertilizer, pesticides, and
irrigation.
1. Biasanya dipraktekkan atas dasar intuitif
2. Memungkinkan penerapan standar lapangan
3. Based on soil types, drainage characteristics,
empirical observation, and ease of boundary
delineation
4. Efisiensi lebih baik dan pencemaran
lingkungan lebih sedikit
SEKALA KECIL.
Small-scale (precision): A system in which
infinitesimal land management units occur within
a single field.
1. Menggunakan GPS dan mengembangkan
basis-data elektronik untuk tanah dan tanaman
2. Memerlukan penerapan beragam teknologi dan
peralatannya
3. Lebih praktis untuk komoditi tanaman yang
nilai ekonominya tinggi
.SAMPLING TANAH.
1. No amount of care in preparation and analysis
can overcome poor or inappropriate soil
sampling
2. Soils vary continuously with space and depth;
you cannot sample all the variability
3. Know your horizons and sample accordingly
when possible
4. We often dig a quantitative pit and get horizon
depths and then sample with augers thereafter
5. Often sampling plow layer in ag soils; this will
NOT work in wildland soils.
KEDALAMAN DAN BANYAKNYA CONTOH
Over-riding guide:
Take a sample so that it represents what it is
intended to represent
1.
2.
3.
4.
5.
Kedalaman lapisan bajak (traditional ag)
At 30 cm (~1 ft) increments; alternate 30 cm increments
Horison tanah untuk sistem yang masih utuh
Tipe tanah
Sampel komposit terdiri atas 5-20 sub-sample untuk
setiap sampel analisis
6. Hara setiap tahun, status garam setiap tahun.
Horizontal variation: sample by landscape strata that make
sense (land use, soil series, slope, aspect, current vegetation,
etc.)
Variasi vertikal:
Perlu diketahui
kedalaman
horison, dan
sampling tanah
pada kedalaman
horison ini
Percent C - ---
Dep th
15 cm
A hor izon
30cm
B horizon
45 cm
60 cm
BC ho rizon
75 cm
90cm
C horizon
Percent C - ---
Dep th
A hor izon
15 cm
E ho rizon
30cm
45 cm
60 cm
Bhs ho rizon
75 cm
90cm
C horizon
Variasi hasil analisis tanah akibat perbedaan kedalaman sampling tanah.
tanah
jelas
Variations in soil analysisBatas-batas
due to samplihorison
ng depth
- clear
boundaries
Depth % N
0 cm
Core 1
0.27%
Core 2
0.16%
Core 3
0. 29%
0.30%
15 cm 0.25%
30 cm 0.05%
45 cm 0.02%
Which
core gave
correct
va lue for %N
soil tanah
%N? Core
is most
representative.
Sample by
Lokasi
manathe
yang
memberikan
yang1paling
tepat?
Lokasi 1 paling
representatif, Sampel tanah menurut horison
horizon
Variasi hasil analisis tanah akibat perbedaan kedalaman sampling tanah.
Variations in soil analysis
due to sampli
ng depth
-diffuse
bound aries
Batas-batas
horison
difuse
(baur)
Depth % N
0 cm
Core 1
0.16%
Core 2
0.08%
Core 3
0. 23%
0.25%
15 cm 0.15%
30 cm 0.05%
45 cm 0.02%
Which
core gave
the yang
correct memberikan
va lue for soil %N?%N
All three
did. yang
With copaling
re 3, youtepat?
wou ld
Lokasi
mana
tanah
want toKetiga
sample at
least one
more depth.
The point
, you must belebih
consistdari
ent with
lokasi
bagus.
Di lokasi
3 issampling
satu
sampling depth
kedalaman
Errors
due to variations
in horizon
thickness
Kesalahan
karena
variasi
ketebalan
Depth % N
0 cm
Core 1
0.29%
Core 2
0.14%
horison tanah
Core 3
0. 11%
0.30%
15 cm 0.15%
30 cm 0.07%
45 cm 0.02%
When
whichmaka
is frequen
tly,dilakukan
you must live
with it. lebih
Pick a akurat
modal depth
and take
Kalauthis
haloccurs,
ini terjadi,
harus
observasi
dan detail.
lots of sample
s. It is always
best todan
measure
depth
at each
pointPada
and average
Tentukan
kedalaman
“median”
ambilhorizon
banyak
contoh
tanah.
setiap this,
titik
diukur
kedalaman horison , dan kalau memungkinkan dirata-rata.
butsampel
no t always
possible.
UJI TANAH
pH, acidity / alkalinity: Electrode in 1:1 or 1:2
soil:water ratio with 0.01M CaCl2. Some people use
distilled water – this generally gives a higher pH –
why? Al, H+ displacement. Also: review lime
requirement.
Garam-garam larut: Saturated paste extract 1:1 or
1:2
Nitrogen: Not reliably precise. Total N, C:N ratio,
extractable ammonium and nitrate, N mineralization,
resins….None cheap or very quantitative.
.UJI P-TANAH
Phosphorus:
The book says this:
• Bray 1: 0.025 M HCl = 0.03 M NH4F (for acidic soils)
• Mehlich 1: 0.05 M HCl + 0.025 M H2SO4 (for acidic soils)
• Olsen’s bicarbonate: 0.5 M NaHCO3 at pH 8.5 (for
neutral and alkaline soils; assumes all goes to H2CO3 in
acidic soils)
• Mehlich 3: 0.2 M acetic acid + 0.25 M ammonium nitrate
+ 0.015 M NH4F + 0.013 M HNO3 + + 0.001 M EDTA
Uji K, Ca, Mg dan S
Potassium, Calcium and Magnesium:
Exchange with ammonium chloride, potassium
chloride or acetate (CEC). No one I know uses
the bicarbonate + DPTA extract mentioned. Total
digests are usually not useful except for
research purposes.
Sulfur:
SO42- is the preferred way, by water, phosphate,
LiCl.
Total S not usually useful except for research,
but with new CHNS analyzers, it is now easy to
get.
Uji Unsur Hara Mikro
Boron: Hot water extract. Some people use cold
water and works just as well.
Zn, Fe, Mn, Cu: Many trials on this using 0.1 M
HCl, Coca-Cola (carbonic acid + sugar), chelates
like DPTA
Mo, Ni: Totals, resins, chelates
Soil tests are changing – resins are coming into
play now and must be checked against older
methods. Also, total analysis may become easier
now, as for example CHNS analysis.
Uji tanah vs. Analisis Tanaman
Leibigs Law of the Minimum:
Growth is limited by the essential nutrient present
in the lowest relative amount.
Thus, the plant is the ultimate judge. However 1. In annual crops, plant analysis may be too
late (already grown)
2. In forests and range, plant analysis is not too
late (growth goes on for years)
3. Plant analysis is generally more sensitive
than soil analysis.
ANALISIS TANAMAN
1. Not generally favored by ag people because it is
"too late“ and doubles the analytical expense
2. Sangat disenangi oleh pakar kehutanan karena
dianggap lebih sensitif - tanaman merupakan
“arbiter” akhir
3. Analisis total tanaman : digunakan untuk risetriset pertanian dan kehutanan
4. Analisis daun, sering digunakan dalam
pendugaan status hara / nutrisi tanaman
5. Analisis kering oven (65oC)
6. Analisis Total - nilai-nilai ambang atau nilai
kritis.
.BATAS AMBANG HARA DALAM TGANAMAN
.
• Analisis vektor untuk menduga respon
pertumbuhan (Bobot + Konsentrasi)
• DRIS (diagnosis recommendation integrated
system)
• Kisaran kritis hara tanaman
• Gejala defisiensi visual
• Mobile nutrients like N, S, P, Mg, K symptoms
appear on older tissues because of
translocation
• Unsur hara Imobil seperti Cu, Mn, Ca, Fe ;
gejala defisinesinya muncul pada jaringan
muda.
UNSUR HARA TANAMAN
Unsur Hara Tanaman
Bagaimana tanaman memperoleh dan menggunakan hara?
1. Mengapa unsur hara itu penting?
2. Apa saja unsur hara esensial itu?
• Sistem klasifikasi hara
3. Unsur hara dalam tanah
• Ketersediaan hara
• Penjerapan oleh partikel tanah
• Efek pH tanah
4. Akar dan penyerapan hara
• Struktur Akar
• Zone penyerapan
4. Mycorrhizae
5. Nitrogen – unsur hara yang biasanya membatasi tanaman
Mengapa unsur hara itu penting?
In most natural soils, the availability of mineral
nutrients limits plant growth and primary
productivity.
Nutrient limitation is an important selective
pressure and plants exhibit many special traits
related to the need to acquire and use mineral
nutrients efficiently.
Apa saja unsur hara esensial?
Hara Makro - present in relatively high
concentrations in plant tissues.
N, K, P, Ca, Mg,S, Si
Nitrogen is most commonly limiting to productivity of
natural and managed soils. Phosphorus is next most
limiting, and is most limiting in some tropical soils.
Hara mikro - present in very low concentrations in
plant tissues.
Ada 17 unsur hara esensial yang
dibutuhkan tanaman
Apa definisi unsur hara “essensial”?
1. In its absence the plant cannot complete a
normal life cycle
2. The element is part of an essential
molecule (macromolecule, metabolite)
inside the plant
 Most elements fall into both categories
above (e.g., structural vs. enzyme cofactor)
 These 17 elements are classified as
 9 hara makro (present at > 10 mmol / kg
dry wt.)
 8 hara mikro (< 10 mmol / kg dry wt.)
Uanru hara mikro dengan konsentrasi sangat rendah
ppm
Very low concentrations, but still essential
because of specialized roles in metabolism
I. Hara Tanaman
 Hara Makro / Mikro



Hydroponics allowed us to see what was needed
The necessary nutrients are those the plant can
not grow with out
Dua Kategori:
 1. Hara Makro (C, O, H, N, S, P, K, Ca, Mg)
 Majority of the time used for the main
organic compounds
 2. Hara Mikro (Cl, Fe, B, Mn, Zn, Cu, Mo, Ni)
 Mostly cofactors for particular enzymes (Fe > Cytochromes
Soils particles are generally negatively charged and so bind
positively charged nutrient ions (cations).
KTK atau CEC: Kemampuan tanah mengikat kation.
NH4+, NO3-, Cl-, PO4-2, SO4-2
pH tanah mempengaruhi ketersediaan hara dalam tanah.
AKAR
Mempunyai
permukaan yang
luas untuk
penyerapan hara
Bulu Akar = Root
hairs
Bulu
akar =
Root
hairs
Zone Penyerapan hara:
Konsentrasi hara menurun
karena diserrap akar
Zone ini di sekitar akar
tanaman
Fig. 5.7
Akar tanaman dan penyerap[an hara dari tanah
Akar-akar halus
dan bulu akar
menyerap hara
dari tanah.
Hifa mikoriza
membantu
penyerapan hara
oleh akar.
Pertukaran Kation antara bulu akar tanaman dengan partikel
liat tanah
K+
K+
K+
Clay
particle
H+
K+
K+
K+
K+
K+
Root hair
Mikoriza VAM (Vesicular
Arbuscular Mycorrhiza)
Di dalam akar tanaman
• Intercellular mycelium
• Intracellular arbuscule
• tree-like haustorium
• Vesicle with reserves
Di luar akar
• Spores (multinucleate)
• Hyphae
•thick runners
•filamentous hyphae
Membentuk jaring-jaring hifa yang
sangat ekstensif
Bakteri fiksasi Nitrogen
Genus: Rhizobium
N2
NH4
Supply of electrons
Fig. 38.07
Penyerapan
ion hara
Penyerapan hara secara aktif
Proton pumps establish an
electrochemical gradient.
Outside
cell
(positive)
Inside cell
(negative)
Net
positive
charge
Net negative
charge
Kation memasuki bulu akar melalui saluran atau Karier
Anion memasuki bulu akar melalui ko-transporter.
Konsep Kadar Kritis Hara tanaman
 Above critical
concentration, there is
no net benefit (e.g.,
yield increase) if more
nutrient is supplied
 Below critical
concentration, nutrient
level limits growth!
 Not shown on diagram:
all elements eventually
become toxic at very
high concentrations
Analisis jaringan tanaman menunjukkan defisiensi hara
Gejala defisiensi muncul kalau hara esensial
tidak ada (tidak cukup)
 Essential because of their
metabolic functions
 Characteristic deficiency
symptoms shown because of
these roles
 Typical deficiency responses are


Chlorosis: yellowing; precursor to
Necrosis: tissue death
 Expressed when a supply of an
essential metabolite becomes
limiting in the environment
 Element concentrations are
limiting for growth when they are
below the critical concentraion

This is the concentration of
nutrient in the tissue just below the
level giving maximum growth
Kurangnya hara akan berpengaruh negatif terhadap
pertumbuhan tanaman
 Plant responses to limiting nutrients usually very
visible: affects yield/growth!
 Again, chlorosis and necrosis of leaves is typical
 Sometimes straightforward relationship

e.g., in chlorosis (lack of green color),


N: chlorophyll component
Mg: cofactor in chlorophyll synthesis
Ctrl
-P
-N
- Ca
- Fe
REKOMENDASI PUPUK
Tujuan:
Menduga jumlah hara yang dibutuhkan untuk
pertumbuhan tanaman.
1. Berdasarkan sejarah lahan dan pertanaman
2. Berdasarkan pada produksi yang jelek atau
perhitungan estimasi serapan hara atanaman.
3. Based on plant or soil analysis; different labs
use different standards so recommendations
may differ
4. Masih belum tuntas, terutama untuk
kehutanan.
KUALITAS PUPUK
1. Grade Pupuk: Jaminan persentase minimum
hara N, P (P2O5), K (K2O)
2. Additional nutrient contents are separately
specified
3. Total weight of bag content
4. Manufacturer
5. Sometimes the filler content and salt index
are specified
6. Beberapa material dapat memebntuk asam.
PERHITUNGAN PUPUK
Note that the three numbers on the bag are N, P
as P2O5, and K as K2O or sometimes KCl
• Note that fertilizers do not actually contain P2O5
or K2O
This is an artifact of very old methods of
analysis where these nutrients were measured by
combustion and ended up as oxides which
needed to be weighed.
• See the calculations on p. 334, 335, and 336; we
will go over these in detail in class
TEKNIK-TEKNIK APLIKASI PUPUK
• Starter: with the seed, low amounts
• Broadcast: spread evenly over the land (lowest
efficiency)
• Tidak dekat akr tanaman, dapat memberi
makan gulma
• Fiksasi P dalam tanah
• Mengapa dilakukan?
1. Cara yang praktis - pastures, etc.
2. Build up stocks in low-fertility soils
3. Mudak dan murah
4. Cara terbaik menambahkan pupuk
kepada tanaman yang telah mulai
tumbuh
TEKNIK APLIKASI UPUPK.
Deep banding ; Dibenamkan ke tanah
1. Kedalaman 10-25 cm, misalnya pupuk anhydrous
ammonium
2. Penempatan pupuk pada lokasi yang dapat
dijangkau oleh akar tanaman
3. Biaya mahal.
•Split Application (Aplikasi ganda, tidak sekaligus)
1. Aplikasi pupuk dua hingga tiga kali
2. Terutama pupuk N, kandungan hara tersedia
dalam tanah akan kembali seperti semula dalam
waktu 4-12 bulan
3. Menyesuaikan dnegan irama penyerpaan hara
tanaman
4. Waktunya kritis
.KAPAN APLIKASI PUPUK?
Sumbangan N-tersedia dalam tanah (dari
pupuk) sudah habis pada Juli-Agustus
NH4 + NO3
Soil
NH4tanah
+ NO3
dalam
Aplikasi
Single
pupuk
sekaligus
fertilization
Aplikasi pupuk
Split application
dua-kali
Mar Apr May June July Aug Sept Oct Nov
Aplikasi ganda vs Tunggal. Kapan puncak penyerapan hara terjadi?
Sumbangan Ntersedia dalam
tanah (dari
pupuk) masih
ada hingga
Nopember
PEMUPUKAN DAN KETERSEDIAAN HARA ATANAH.
Recall that
fertilization withP,P,K,Mg
K, Mg,dan
and other
can dapat
(but maymenjaga
not) keep soil
Pemupukan
haranutrients
lainnya
available
levels elevatedhara
for a very
longdalam
time whereas
this never
happenstetapi
with N tidak
ketersediaan
tanah
jangka
panjang,
demikian halnya dnegan nitrogen
N ( juga dapat terjadi pada P)
Soil
Hara
terAvail
sedia
dalam
Nutr
Dapat terjadi pada P; juga berlaku bagi K, Ca, Mg
tanah
N tersedia dalam
tanah mudah
hilang
1
2
3
4
6
7
8
9
Years
Tahun
10
11
12
13
.TEKNOLOGI APLIKASI PUPUK
1. Side dressing: setelah tanaman tumbuh
2. Point Injector fertilization: using a rod to
make a hole, put fertilizer deep near plant.
3. Dollop or tree tablet principle.
4. Fertigation: pupuk ditambahkan bersama
dengan air irigasi:
1. Tidak sama dnegan aplikasi daun.
2. Obviously require irrigation equipment;
not normal for forests or range soils
3. Sangat efisien
4. Biayanya mahal
APLIKASI PUPUK DUAN
• Aplikasi pupuk melalui daun (Foliar application)
1. Bertujuan untuk penyerapan hara
lewat daun
2. Seringkali dilakukan untuk
mensuplai unsur mikro, kalau
diberikan melalui tanah akan
mengalami imobilisasi hara
3. Memerlukan bahan pembasah dan
bahan perekat
4. Respon tanaman cepat
.EFISIENSI PUPUK
1. Didefinisikan sebagai persentase pupuk yang
secara aktual digunakan oleh tanaman; atau
diukur dalam bentuk hasil tanaman dan
keuntungan
2. Generally 30-70% for N, 5-30% for P, 50-80%
for K in crops, according to the book (sounds
high)
3. Generally 5-40% for N, P, and K in trees,
counting only what is in trees at any one time
4. However, trees recycle nutrients, and forest
floor contents can be re-used
5. Tidak mudah menilai dalam persentase.
.EFISIENSI PUPUK
• Mengapa efisiensi pupuk relatif rendah?
1.
2.
3.
4.
5.
6.
Imobilisasi oleh mikroba tanah
"Fixation“ P dalam tanah
Jenis hara keliru
Waktu aplikasi pupuk tidak tepat
Dosis pupuk tidak tepat
Too low feeds microbes, which are
most efficient competitors
7. Too high in the case of N causes
nitrate leaching losses