STDF - CABI - ICCO PROJECT: TRAINING OF FACILITATORS

MOUNT KINABALU HOTEL HERITAGE & SPA KUNDASANG, RANAU SABAH

Roles Of Soil Types and heavy metals in

Cocoa Productions Edwin Mujin (MCB)

Introductions

What is soil?

Soil is the mixture of minerals, Organic mater,

gases, liquids and a myriad of micro- and macro-

organisms formed from combined effect of

physical, chemical, biological

and anthropogenic processes working on soil

parent material

Parent material?

Rocks

What is soil to cocoa plant?

Where the plant are planted.

Main source of nutrient uptake.

Source of water

Where the roots of the plant grows

Introductions

Common Soil Taxonomy

Oxisols- Have Oxic Horizon less than 16meq/100clay

Good structure

Low Fertility

Ultisols- 20% increase clay, less than 35% Base saturations

Argillic horizon

Low fertility

Common name red clay soils

Alfisols

Simmilar to Ultisols but higher fertility.

Aridisols Soil with aridic moisture regime (Dry Soils).

Incptisols Young soil

Entisols Recently develop ( light development)

Have man made horizon.

Vertisols Cracky clayey soil

Shrink and Swell with moisture

Mollisols Have mollic epipedon (high organic matter)

Soft when dry

Grassland of former grassland

Common Soil Taxonomy- cont

Spodosols Sandy/ Bris Soil

Have Spodic horizon

Iron Accumilation.

Histosols Organic Soils

More than 20% Organic mater

Common Soil Taxonomy- cont

Soil Chemical properties for Cocoa

Soil properties Suitability

pH (H2O) 5.5-6.5

Cation Exchange Capacity (CEC) (cmol(+)kg-1) > 12

Base saturation (%) > 35

Organic matter (%) 3.5 (2.0 % C)

Conductivity (mmhos cm-1) < 1.0

Fertility:

i. Total N (%) > 0.16

ii. Avail. P (ppm) > 15

iii. Exch. K cmol(+)kg-1 > 0.24

iv. Exch. Ca cmol(+)kg-1 > 2.5

v. Exch. Mg cmol(+)kg-1 > 2.0

Aluminium saturation (%) < 30

Carbon/Nitrogen (C/N) > 9

Soil Properties Suitability

Depth of soil (cm) > 100

Depth to acid sulphate layer (cm) > 100

Slope/gradient (o) 0-30o (0-60%)

Gravel/stone content < 25% or below 75cm from soil surface

Soil drainage Good, water table below 90cm from soil

surface

Flood None

Thickness of peat < 20cm

Texture 25-40% clay, 35-65% sand,

Soil physical criteria for cocoa

25-40% clay, 35-65% sand,

Soil where Cocoa are Planted in Malaysia

Peninsular

3 types of soil where cocoa are planted:

Coastal Alluvial Clay Soils. Alluvial soil that formed on/from sea silt

Example:

o Selangor (Kuala Selangor dan Sabak Bernam)

o Perak (Hilir Perak dan Manjung)

o Johor (Batu Pahat dan Pontian)

Selangor, Briah, Bernam, Tualang

Alluvium Soil

soil that formed from new alluvial riverbed

Example:

o Manjung and Inland Johor

Briah, Telemong, Akob, Carey

Inland Soil Jerangau, Segamat, Manchong, Bungor, Rengam,

Serdang, Prang, Jerangau.

Soil where cocoa are planted

Sabah Region

There are 14 main soil group in Sabah 42 units and 103 families

Tawau The soil types are derive from various parent materials such as alluvium, basalt, larva and basic dust,

basic and intermediate igneous rocks, sand stone and shale and acidic volcanic ash.

In general, the fertility status of majority of the above soils are low, particularly phosphorus (P). . Darau, Numatoi, Lumpongon, Talid

Sandakan The dominant soil parent materials in the Sandakan division are sandstone, shale and a combination of

both.

All the soils are generally acidic (pH 4-5) and liming is essential for cocoa cultivation.

The main soil units and families are Ferric Acrisols (Sipit, Batang), Haplic Acrisols (Kumansi, Tanjung Lipat, Kapilit), Ferric

Luvisols (Lumerau) and Haplic Luvisols (Lumpongon).

Interior and West Cost

Areas suitable for cocoa are along riverbanks in Tenom and the main soil families

are Darau, Buran, Sabor and Pegalan

poor texture and drainage

shallow soil depths

Sarawak There are 11 main soil group in Sabah 45 units and 145 families

Main family and soil series are:

Semilajau (Semilajau, Sebako, Julan) marginal (tekstur)

Alluvial Bemang (Bemang, Sebat, Dapoi)

Seduau (Seduau, Malang, Paku, Sekati, Terbat dan

Ramun).

Red-Yellow Podsolic

Interior

Oxisols

Soil where cocoa are planted

Heavy Metals

Definition of Heavy metals A heavy metal is a member of a loosely defined subset of elements

that exhibit metallic properties. It mainly includes the transition

metals, some metalloids, lanthanides, and actinides.

Other name toxic metals

Types of Heavy Metals Can be group in to two:

Cationic heavy metals

Metallic elements whose forms in soil are

positivly charged cations

Mercury(Hg),Cadmium (Cd), Lead(Pb),

Nickel (Ni), Copper (Cu), Zinc (Zn),

Chromium (Cr) and Manganese (Mn).

Anionic compounds

elements whose forms in soil are combined

with oxygen and are negatively charged e.g.,

MoO42-

Arsenic (As), molybdenum (Mo),

selenium(Se), and boron(B).

Hazard of heavy metals

Excess heavy metal accumulation in soils is toxic to humans and

other animals. Exposure to heavy metals is normally chronic

(exposure over a longer period of time), due to food chain transfer.

Acute (immediate) poisoning from heavy metals is rare through

ingestion or dermal contact, but is possible. Chronic problems

associated with long-term heavy metal exposures are:

Lead - mental lapse.

Cadmium - affects kidney, liver, and GI tract

.

Arsenic - skin poisoning, affects kidneys and central nervous

system.

Factors that contribute heavy metals in soil

Impurities in mined mineral fertilizer and soil amendment such as phosphate and dolomite.

Organic fertilizer such as chicken dung due to the usage of saw dust and animal feed that consist contaminant.

Even the use of mill bio product are high in heavy metals

contaminants. Such as POME and EFB

Atmospheric pollutions.

Existing heavy metal in soil. Naturally or antropogenic.

Heavy metals in different soil types

mg kg 1

Soil Order Avail. P As Cd Co Cr Cu Hg Ni Pb Zn

All Malaysian soils (N = 241) 375 16.8 0.12 2.8 25.9 16.4 0.147 13.7 26.4 38

Alfisols (N = 4) 7.9 7.2 0.05 18.4 8.6 22.3 0.07 13.4 28.7 60.7

Anthropogenic soil (sand mine

tailings)

471 7.1 0.13 2.2 18.5 22.1 0.1 8.9 30.2 54.8

Entisols (Flooded paddy) (N = 7) 19.9 3.9 0.06 2.2 26.3 6.2 0.09 8.2 27.2 31

Entisols (other crops) (N = 15) 125 14.6 0.07 0.91 16.1 5.8 0.07 20.5 15.5 24.8

Histosols (peat) (N = 8) 510 55 0.4 2.2 22.1 47.2 0.24 6.8 23.9 40

Inceptisols (Acid sulphate) (N = 6) 29.8 16.4 0.06 1.9 26.5 10.1 0.12 8.1 29 27.6

Inceptisols (Flooded paddy) (N = 11) 29.8 10.9 0.09 2.2 27.7 10.9 0.06 13.2 28.7 25.6

Inceptisols (muck) (N = 22) 519 12.4 0.17 1.9 22.8 20.8 0.2 8.7 28.4 33.1

Inceptisols (other) (N = 8) 1340 34.5 0.17 2.5 31.7 37.6 0.1 12.6 26.3 58.1

Oxisols (N = 41) 697 14.8 0.1 4.2 30.2 17.9 0.13 12.7 18.8 33.8

Spodosols (N = 17) 246 1.7 0.06 0.21 4.9 8 0.06 2.2 6.4 11.6

Ultisols (N = 58) 288 22 0.12 3.5 38 13.6 0.14 20.4 31.3 53

Assoc. of Ultisols and Oxisols (N = 27) 208 6.7 0.08 1.1 17.8 6.9 0.14 19.7 36.8 31.1

Ultisols (Acid sulphate) (N = 3) 18.2 8.9 0.02 1.5 19.3 3.7 0.15 5.5 20 18.5

Heavy metals in different soil types

Arsenic in different soil types

Cadmium in different soil types

Cobalt in different soil types

Cromium in different soil types

Copper in different soil types

Lead in different soil types

Mercury In different soil types

Nickel In different soil types

Zinc In different soil types

Heavy Metals in cocoa plants

As Cd Cr Cu Hg Ni Pb Zn

Soil Plant Soil Plant Soil Plant Soil Plant Soil Plant Soil Plant Soil Plant Soil Plant

30 1.21 0.11 0.666 35 0.49 11 14.1 0.16 15 13 4.5 26 0.29 39 52

mg kg1 except plant Hg g kg1

Management of Contaminated Soil

Soil and crop management methods can help prevent uptake of pollutants by plants, leaving

them in the soil. The soil becomes the sink, breaking the soil-plant- animal or human

cycle through which the toxin exerts its toxic effects (Brady and Weil, 1999). The

following management practices will not remove the heavy metal contaminants, but

will help to immobilize them in the soil and reduce the potential for adverse effects from

the metals - Note that the kind of metal (cation or anion) must be considered:

1. Increasing the soil pH to 6.5 or higher.

Cationic metals are more soluble at lower pH levels, so increasing the pH makes them less available

to plants and therefore less likely to be incorporated in their tissues and ingested by humans. Raising

pH has the opposite effect on anionic elements.

2. Draining wet soils.

Drainage improves soil aeration and will allow metals to oxidize, making them less

soluble. Therefore when aerated, these metals are less available. The opposite is true

for chromium, which is more available in oxidized forms. Active organic matter is

effective in reducing the availability of chromium.

3. Applying phosphate.

Heavy phosphate applications reduce the availability of cationic metals, but have the

opposite effect on anionic compounds like arsenic. Care should be taken with

phosphorus applications because high levels of phosphorus in the soil can result in

water pollution. Impurities In phosphate fertilizer also may contain heavy metals.

Thank You