2.Soil Suitability for Crop Pdn

Soil Suitability and management for crop production


Abstract:

Successful crop management relies on selecting suitable crops to the type of soil present in that region. Most of crops prefer well drained medium textured soils with optimum physical properties and neutral pH.

Alluvial soils prevails in river basins and deltas suits well for cultivation of rice, maize, groundnut, sugarcane, sunflower, cotton etc.

Crops such as cotton, sorghum, millets, pulses, are predominantly grown in black soils which are having workability limitations


Red soils are mainly suits for many agricultural and horticultural crops.

Laterite soils are well suited for cultivating cashew, coconut, coffee crops; however, these are mainly used as building materials.

Desert and mountain soils are lesser extent used for crop cultivation.

In Saline and sodic soils are problematic soils where salt causes great menace and crop production can be carried out with suitable management practices.


Learning objectives:

To learn the different types of soils and their suitability for crop production.

To study the various constrains and management strategies for better crop production in different soils.

Introduction:

Soil is an important natural resource for crop production.

It is the top layer of the earth’s surface and is made up of disintegrated rocks, minerals, organic matter and bacteria. Soils are varying in nature and they are classified to several types based on the characteristics.


Although some plants may be found to grow in poor soils and under extreme climatic conditions, yet not all plants can grow in a particular soil and climatic conditions.

Since the availability of both water and plant nutrients is largely controlled by the physico-chemical and micro environment of soils, the success and failure of any plant species, in a particular area is largely determined by these factors.

The objectives of such soil site suitability evaluation studies have been to predict and classify land in different suitability classes for plant growth.


The deep rooted forest plantation crops, respond differently to

soil depth (and texture) than the shallow rooted arable crops, such as

wheat, rice, sorghum, pigeon pea, groundnut, etc.

Within different arable crops, groundnut grows well on shallow

sandy soils whereas wheat and cotton thrive well on comparatively

deep and clayey soils (Sehgal, 2005).


Suitability criteria

Most of the plant species need well drained, moderately

fine to medium textured soils, having optimum physical and

chemical properties.

Soil resource maps, based on such parameters, can aid in

predicting the behaviour and suitability of soils for growing

different crops and forest species, once the suitability criteria for

each crop is established.

Within limits, it may also find application in other areas

having comparable soil-site characteristics.


Alluvial soil

Alluvial soil is found mostly in the flood plains and deltas.

It is major soil type found in India (Biswas and Mukherjee,

2005). It generally is light to dark in colour.

Alluvial soil also is rich in potassium and has high fertility.

Because of the injudicious use of irrigation water, some such

soils have been rendered waterlogged and pose problems of soil

salinity and /or sodicity.

These soils are deficient in nitrogen, phosphorus and

humus and require application of manures and fertilizers for

sustainable farming.


Because of intensive cultivation, with wheat and paddy over

years (in countries like India), these soils have developed second

generation problems, such as nutrient deficiencies (sulphur and zinc)

receding groundwater- table in some areas and its rise causing

salinisation in other areas rendering the soils water logged or saline.

These soils are one of the best agricultural soils and are used

for growing most crops such as wheat, paddy, maize, groundnut,

potato, cotton, sunflower, sugarcane, etc.


Management:

Providing suitable drainage facilities are mandatory in

waterlogged areas which also alleviate the further problems like

salinity and sodicity.

Since these soils are deficit in N and P, incorporation of green

manures, application of organic manures, improves the soil fertility

levels.

If iron deficiency occurs, soil application or foliar spraying of

iron sulphate is must

Continuous monocropping may be avoided to reduce the ill

effects of deficiency of nutrients.


Black soil

Black soil is formed due to the disintegration of lava rocks. Black soil is rich in nutrients like calcium, potassium and magnesium, but has poor nitrogen content.

Iron deficiency may prevail because of high calcium content. Black cotton soils are difficult to work and / or manage.

They are very hard consistence when dry and very plastic and sticky when wet.

Mechanical tillage in the wet season causes serious soil compaction. The salinity and sodicity may develop under irrigated conditions, but they are rare under natural conditions.


Their overall productivity remains low, especially where no irrigation water is available.

Due to swell shrink nature, these soils are unsuitable for laying foundations, construction of buildings, laying of gas and water pipelines and electric communications, etc.,

The soils are inherently very fertile and under rain fed conditions, they are used for growing crops such as cotton, sorghum, millet, soybean or pigeon pea during monsoon rainy period.

Under irrigated conditions, they can be used for a variety of other crops, such as sugarcane, wheat and or citrus plantation crop.


Management:

Ploughing at optimum moisture condition improves the soil

physical properties since workable moisture range is narrow

Crop selection is most important aspect since these soil may

not suit for many crop cultivation because of calcareousness

/salinity/sodicity problem.


Red soil

Red soil gets its red colour due to the presence of iron

oxide in the soil. The soil is formed because of the disintegration

of metamorphic and igneous rocks.

It has highly varying soil texture that makes them most

prone to surface crusting and hardening. Soil depth, particularly

on hills and hill slopes, where the soils mostly prevails, are

gravelly or skeletal in nature.

Red soils have low water and nutrient holding capacity

because of texture and dominant presence of illite and kaolinite

clay minerals


Low cation exchange capacity, high point of zero charge and

high phosphorus adsorption are some of other constraints of the red

soils.

Depth of red soils varies very widely and hard pan formation

may occur frequently. This hard pan in turn result in poor anchorage

to the crop, low infiltration of water and high run off and soil erosion.

Under good management practices, these soils can be profitably

used for a variety of agricultural, horticultural and plantation crops


Management:

Soils are light textured and needs light and frequent irrigation

(micro irrigation) to maintain the soil at field capacity levels.

Sub-soil hard pan be broken by using chisel ploughs once in

two to three years.

Application of lime and organic manure improves the physical

properties and fertility level.


Laterite soil

Laterite soil is formed from a mixture of clay and red soil. It

has very low fertility and becomes hard when exposed to the air.

The soil is generally a brown to yellowish colour. It is most

often used as a building material.

However, some crops like coffee, coconut and cashew are

capable of growing in laterite soil.


Management:

Soils are light textured and needs light and frequent

irrigation (micro irrigation) to maintain the soil at field capacity

levels.

Organic amendment and green manures addition increases

the soil fertility status.

Desert soil

Desert soil is most often found in the arid and semi-arid

regions. The soil is light brown to reddish color. It is

characterized by its salinity and sandy texture having very low

moisture retention capacity. The soil is best suited for drought-

resistant crops like millet and barley


Management:

Identification of drought resistant cops are the most pre-

requisite since, these soils suits for narrow range of crops.

Artificial irrigation may be arranged in moisture sensitive

stages.

Mountain soil

Mountain soil is found in the hill slopes. It is dark brown to

black color. The soil is formed by the deposition of organic matter

from the forest. Tropical fruits, coffee and spices are some of the

crops suitable for growth in mountain soil.


Management:

Since the soil location is in mountain region, there is less

scope for management options. However, erosion control

measures such as contour bunding, graded bunding, bench

terracing, and biological components based on the requirement

not only conserve the soil, but also, moisture.

Salt affected soils

Salt affected soils are the soils that contain considerable

amounts of soluble salts and /or sodium on the exchange

complex.


Evapotranspiration greatly exceeds precipitation in

arid and semi-arid regions of the world.

The high amount of soluble salts (in saline soils) and

of sodium on the exchange complex (in sodic soils) hinder

crop growth and have rendered them barren (Gupta and

Abrol,1990).

In saline soil the available moisture range is low and

crop has to spend more energy to extract water from the soil

because of high osmatic potential of the soil solution.


These also adversely affect water and nutrient availability

and induce micronutrients deficiency. Such soils have a calcic, or

petrocalcic or duripan that acts as a barrier for root penetration

and development.

Management of Saline soils

In saline soils, the problem is high concentration of soluble

salts in the rooting zone. For efficient crop production, the excess

salts must be leached from the rooting zone.

The saline soils, once leached of the excess salts, are used

for growing salt tolerant crops.


The coastal saline soils are generally used for growing paddy,

coconut or other agro climatically suitable crop.

If irrigation water is saline in nature, micro irrigation may be

followed and cropping may be avoided during summer season to

reduce the salt buildup in the soil

Agronomic approaches like cultivation of crops in broad bed

and furrow system , ridges and furrows may be followed to avoid

direct contact of roots with salt


Sodic soils:

Despite many limitations, the sodic soils, once ameliorated

partially, by using gypsum technology, are used successfully for

growth sodium- tolerant or semi tolerant crops, such as rice,

sugarbeet, wheat, barley, amla etc.

Provision should be made for proper drainage, judicious supply

of irrigation water, farmyard or green manure and fertilizers to boost

the agricultural production.

Application of excess nitrogenous fertilizer to compensate

ammonia volatilization loss


Summary:

Most of the crops need well drained, medium textured and salt free soils, and soils having optimum physical , chemical and biological properties.

Alluvial soil is found mostly in the flood plains and deltas and is one of the best agricultural soils and is used for growing most crops. Suitable drainage facilities are mandatory in waterlogged areas which also alleviate the further problems like salinity and alkalinity.

Black soils are very hard consistence when dry and very plastic and sticky when wet.


Preparatory cultivation should be carried out at optimal moisture condition.

They are used for growing crops such as cotton, sorghum, millet, soybean or

pigeon pea. Crop selection is most important aspect in management since

these soils may not suits for many crop cultivation.

Red soil has highly varying soil texture that makes them most prone to

surface crusting and hardening.

Under good management practices, these soils can be profitably used for a

variety of agricultural, horticultural and plantation crops. Red soils are light

textured and needs light and frequent irrigation to maintain the soil at field

capacity levels


Laterite soil has very low fertility and becomes hard when exposed

to the air some crops like coffee, coconut and cashew are capable of

growing in laterite soil. Organic amendment and green manures addition

increase the soil fertility status.

Desert soil is most often found in the arid and semi-arid regions.

The soil is best suited for drought-resistant crops like millet and barley.

Identification of drought resistant cops is the most pre-requisite since,

these soils suits for narrow range of crops.


Salt affected soils are the soils that contain considerable amounts

of soluble salts and /or sodium on the exchange complex. In saline

soils, the problem is high concentration of soluble salts in the rooting

zone.

Despite many limitations, the sodic soils, once ameliorated

partially, by using gypsum technology, are used successfully for

growth sodium- tolerant or semi tolerant crops, such as rice, sugarbeet,

wheat, barley etc.

Assessment

1.Most of the crops need well drained, medium textured soils with

neutral pH (True /False)

2.Major soil type found in India is Red soil (True /False)

3. Black soils is one of the best soils and is used for growing most

crops (True /False)

4. Black soils are preferred for rainfed cotton cultivation (True

/False)

Assessment

5.Surface crusting and hardening are the major problems of red

soils (True /False)

6.Desert soil is suitable for growing drought-resistant crops like

millet and barley (True /False)

7.In sodic soils, the problem is high concentration of soluble

salts in the rooting zone (True /False)

8.Sodic soils are ameliorated by using gypsum (True /False).

References

Biswas, C.R. and A.K. Bandyopathyay. 1987. Agronomy of rice in coastal saline soils – a review. Journal of Indian Society of Coastal Agricultural Research, 5: 15-23.

Biswas, T.D and S.K. Mukherjee, 2005. Textbook of Soil Science: 2nd edition. Tata McGraw-Hill Publishing Company Limited, New Delhi.

Gupta, R.K. and I.P. Abrol. 1990. Salt–affected soils – Their reclamation and management for crop production. Advances in soil science 12,223-275.

Sehgal, J, 2005. A textbook of Pedology: Concepts and applications: 2nd edition. Kalyani Publishers, Ludhiana.

www.apps.caes.uga.edu/sbof/main/lessonPlan/soilType.pdf

2.Soil Suitability for Crop Pdn

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