tanah 1

Apa itu tanah?

• Tanah membentuk bahagian atas permukaan planet kita.

• Topsoil adalah bahagian/ lapisan tanah yang paling productive.

• Tanah mengandungi banyak jumlah organic matter (living and dead organisms), minerals and nutrients.

• Lima ton topsoil boleh meliputi seekar kawasan hanya setebal syiling 10 sen.

tanah 2

• Proses semulajadi mengambil masa lebih 500 tahun untuk membentuk one inch of topsoil.

• Tanah formed from rocks and decaying plants and animals.

• An average soil sample is 45 percent minerals, 25 percent water, 25 percent air, and five percent organic matter.

• Different-sized mineral particles, such as sand, silt, and clay, give soil its texture.

tanah 3

• Fungi and bacteria help break down organic matter in the soil.

• Plant roots and lichens (lumut) break up rocks which become part of new soil.

• Roots loosen the soil, allowing oxygen to penetrate. This benefits animals living in the soil.

• Roots hold soil together and help prevent erosion.

tanah 4

• Five to 10 tons of animal life can live in an acre of soil.

• Earthworms digest organic matter, recycle nutrients and make the surface soil richer.

• Mice take seeds and other plant materials into underground burrows (lubang bawah tanah), where this material eventually decays and becomes part of the soil.

• Mice, moles, and shrews dig burrows which help aerate the soil.

tanah 5

• Dalam pertanian bentuk tanah selalunya merujuk kepada perbezaan saiz butiran mineral.

• Tanah terjadi daripada sebahagian batuan yang bertukar menjadi saiz sand, silt atau clay yang dengan fungsi tertentu;– The largest particles, sand, determine aeration and

drainage characteristics,

– The tiniest, sub-microscopic clay particles, are chemically active, binding with water and plant nutrients.

– The ratio of these sizes determines soil type: clay, loam, clay-loam, silt-loam, and so on.

tanah 6

:

A) Humus : bahan organik dalam bentuk undecomposed spt daun, ranting dllB) Topsoil: well decomposed organic matter, mixed with a smaller amount of minerals C) Lapisan campuran decomposed organic matter and mineral content. D) Lapisan subsoil or mineral the content of which varys according to the nature of the soil and its parent material. E) Bedrock or parent material, which breaks down at the upper surface due to the effects of weathering and decay.

tanah 7

• Topsoil dibahagian atas lapisan tanah, selalunya the top six to eight inches. It has the highest concentration of organic matter and microorganisma and tempat dimana aktiviti mikroorganisma berlaku.

• Tanaman selalunya concentrate their roots in, and obtain most of their nutrients from this layer.

• Topsoil boleh disukat ketebalannya from the surface.

• Without topsoil, little plant life is possible.

tanah 8

Soil is made up of four main components: mineral, water, air and organic.

• MINERALThe mineral component is non-living material. It is divided by the size of the particles, into:

1. Sand/pasir: Rounded particles 1/12 to 1/500 inch (2.0 to 0.06 millimeters) in diameter.

2. Silt/lumpur: Rounded particles 1/500 to 1/12,500 inch (0.06 to 0.002 millimeters) in diameter.

SOIL COMPONENTS

tanah 9

3. Clay/tanah liat: Flattened particles less than 1/12,500 inch (0.002 millimeters) in diameter.

4. Loam/gembur: Mixture of the above in roughly equal proportions.

tanah 10

Sifat Pasir Tanah liat

Tekstur Terbuka, ringan, mudah dikerjakan, mudah pengakaran

Tertutup, berat, sukar dikerjakan dan ditembusi akar

Kandungan udara

Tinggi (ruang besar) Rendah (butir kecil melekat rapat)

Keronggaan Sangat berongga,air mudah mengalir

Tidak berongga, air sukar mengalir

Keupayaan simpan air

Lemah (mudah kering) Baik (mudah menakung)

Kandungan humus

Kurang Kurang

Kandungan garam

Rendah (kerana larut lesap)

Sederhana rendah (kerana kekurangan sisa organik)

Perbezaan antara pasir dengan tanah liat

tanah 11

Tanah gembur• adalah campuran antara pasir tanah liat dan

humus (dimana jumlah pasir dan tanah liat sama banyak)

• tanah ini subur dan kesuburanya bergantung kepada jumlah pelbagai juzuk yang terkandung didalamnya

• saiznya sedang butiran membuatkan teksturnya sederhana antara pasir dan tanah liat

tanah 12

Water• The amount of water in the soil is described in

these ways:

1. Saturated/tepu : All of the spaces in the soil are filled with water.

2. Field capacity/keperluan: Excess water has drained away leaving a film of water on each particle and air in the spaces.

3. Wilting Point/tahap layu: The film of water on each particle is so thin that roots can no longer pull enough water from the soil, so the leaves droop.

tanah 13

Udara

• Tanah yang subur seharusnya bertekstur sederhana (tidak terlalu terbuka atau tertutup) berudara dan oksigen yang cukup untuk respirasi akar dan pengikatan nitrogen

• Air in the soil is made of the same gases (seperti udara di atmosphere)

• Air doesn’t move as freely in the soil (oleh ianya bermungkin banyak atau sedikit).

• Plant roots need oxygen to absorb water and nutrients. Kekurangan oxygen limits how deep roots can grow.

tanah 14

• Akar boleh tumbuh sedalam 30ka in well-drained sandy soil, but most roots are in the top foot of clay soil.

• Oxygen bertukar/ tambah dalam tanah bila water forces the air out of the soil, then fresh air is pulled back into the soil as the water drains away.

• Large spaces between soil particles and crumbs/serpihan allow soil to breathe better.

tanah 15

ORGANIC

The organic component of the soil is made up of living and dead plants and animals.

1. Living: Bacteria, Fungi, Insects, Worms, and Roots.

2. Dead: All of the above as they decay.

3. Humus: Dead organic matter that has decomposed until it is very fine, black and sticky.

tanah 16

Miro-organisma dan cacing

• Bakteria dan kulat menolong menguraikan benda-benda organik supaya menjadi humus (dan membentuk nitrat dan lain-lain organik yang diperlukan tumbuhan)

• Cacing menolong menggemburkan tanah dan membaiki keadaan tekstur tanah

tanah 17

• Good soil mengandungi 93% mineral dan 7% bahan bio organic. The bio organic parts are 85% humus, 10% roots and 5% edaphon.

• Edaphon is itself a "world" of life and consists of microbes, fungi, bacteria, earthworms, micro fauna, and macro fanuna as follows: The Edaphon consists of: – fungi/algae .........................40% – bacteria/actinomycetes..……….40% – Earthworms.........................12% – Macrofauna.....................……. 5% – micro/mesofauna...........……... 3%

tanah 18

Humus

• Humus adalah campuran pejal yang meleket, ringan dan lembab yang terbentuk dari bahan organik reput (tumbuhan / haiwan mati yang kaya dengan nitrat)

• Sebahagian besar koloid (seakan-akan bahan pelekat) yang menyerap garam galian (nitrat, posfat, kalium dan natrium) supaya mencegah dari larut lesap

• Juga memberi keupayaan kepada tanah pasir menyimpan air

tanah 19

• Bacteria dan kulat menyerap nutrients from the soil minerals and make them available (sesuai) to plants.

• Insects and worms create air passages (liang udara) deep into the soil.

• Dead organic material provides rich nutrients for the living. It also holds the nutrients from applied fertilizers until the plants can use them.

• Humus sticks the soil particles into larger

crumbs/serpihan so there are bigger spaces (luas permukaan) for air and water.

tanah 20

• Dead organic matter is decaying continually (pereputan berterusan), so it needs to be ditambah every year.

• Pembajaan nitrogen yang melampau will cause the dead organic matter to decay even faster; so more organic matter will have to be applied.

• Kelalaian menggunakan pesticides may harm or kill the living organisms and damage the soil.

tanah 21

SOIL pH OR ACIDITY TEST

• pH tanah ialah kiraan kepekatan ion hirogen yang boleh diuji dengan chemical pH test atau dengan pH meter.

• Jika nilai pH 7.0 ianya neutral dan 4.0 sangat berasid manakala 10.0 sangat alkaline.

• Hujan banyak dan tinggi bahan organik akan menghasilkan tanah berasid

• Hujan kurang dan tinggi pengapuran akan menjadikan tanah beralkali.

tanah 22

• pH sangat penting untuk organic gardener kerana beberapa sebab

– sesetengah diseases cenderong membiak when the soil is alkaline or acidic,

– kebanyakkan plants and soil life forms prefer (memilih) either acid or alkaline conditions,

– and that the pH can affect (memberi kesan) the availability (ketersediaan) of nutrients in the soil.

tanah 23

• Lawns, roses, lilacs, fruit trees, vegetables and many flowers prefer a soil pH near neutral, 6.5 to 7.0.

• Kebanyakan plant nutrients selalunya kedapatan antara asid ke neutral,

• Asid tanah boleh dikurangkan dengan pengapuran (calcium carbonate), atau more acid dengan mencampur sulfur or aluminum sulfate

• Lime boleh menaikan soil pH dalam beberapa minggu/ bulan bergantung kepada berapa halus patikel kapur yang digunakan.

• Sulfur mengambil masa bertahun-tahun untuk menurunkan pH sementara bacteria diperlukan untuk melengkapkan proses. 

tanah 24

• pH level of around 6.3-6.8 is also the optimum range yang diperlukan oleh kebanyakan bakteria tanah, kulat, molds, and anaerobic bacteria have a broader tolerance and tend to multiply at lower pH values.

• More acidic soils tend to be susceptible mempengaruhi kemasaman and kereputan, rather than undergoing the sweet decay processes associated with a healthy, living soil.

Determining pH• pH is not constant(tetap) in soil or water, but varies on a

seasonal or even daily basis due to factors such as – rainfall, – biological growth within the soil,– and temperature changes.

tanah 25

• pH mempamerkan vertical gradients, mirip kepada more acidic in surface mulches (bersungkup) and alkaline where evaporation, wormcasts (tahi cacing), and capillary action draw bases up to the soil surface.

• Perbeza besar juga bergantung kepada factors such as slope, rocks, and vegetation type/ jenis tumbuhan.

Nutrient availability in relation to soil pH

• The majority of food crops memerlukan a neutral or slightly acidic soil, kerana the solubility of most nutrients necessary for healthy plant growth is highest at pH 6.3-6.8. Some plants however prefer more acidic (e.g., potatoes, strawberries) or alkaline (brassicas) conditions

tanah 26

• When the pH falls below 5.5, kebanyakan major plant-nutrient minerals (N,P,K,S,Mg) dan (Ca & mikronutrien) become insoluble and hence unavailable for uptake by plant roots.

• Kebanyakan cationic (positively charged) nutrients such as zink (Zn2+), aluminiam (Al3+), besi (Fe2+), tembaga (Cu2+), kobalt (Co2+), and manganese (Mn2+) are soluble and available for uptake by plants below pH 5.0, although their availability can be excessive (berlebihan) and thus toxic in more acidic conditions.

• In more alkaline conditions they are less available (kurang), and symptoms of nutrient defficiency may result,(thin plant stems, yellowing/ chlorosis or mottling of leaves, and slow or stunted growth.

tanah 27

• pH levels also affect the complex interactions among soil chemicals. – Phosphorus (P) for example requires a pH

between 6.0 and 7.0

– and becomes chemically immobile outside this range

– forming insoluble compounds with iron (Fe) and aluminium (Al) in acid soils and with calcium (Ca) in calcareous soils.

tanah 28

This table indicates the availability of several nutrients at various pH values:

Acid Neutral Alkali

4   4.5 5   5.5 6   6.5 7   7.5 8   8.5 9   9.5 10

nitrogen, N

phosphorus, P

potassium, K

calcium, Ca

magnesium, Mg

sulfur, S

iron, Fe

manganese, Mn

boron

, B

copper, Cu

zinc, Zn

molybdenum

, Mo