2.Soil Suitability for Crop Pdn (1)

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 earths 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.

Soil Suitability and management for crop productionAlthough 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.

Soil Suitability and management for crop productionThe 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 criteriaMost 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.

Soil Suitability and management for crop productionAlluvial soilAlluvial 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.

Soil Suitability and management for crop productionBecause 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.

Soil Suitability and management for crop productionManagement: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 mustContinuous monocropping may be avoided to reduce the ill effects of deficiency of nutrients.


Black soilBlack 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.

Soil Suitability and management for crop productionTheir 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 narrowCrop selection is most important aspect since these soil may not suit for many crop cultivation because of calcareousness /salinity/sodicity problem.


Red soilRed 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 soilLaterite 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 soilDesert 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

Soil Suitability and management for crop productionManagement: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 soilMountain 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 soilsSalt affected soils are the soils that contain considerable amounts of soluble salts and /or sodium on the exchange complex.

Soil Suitability and management for crop productionEvapotranspiration 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.

Soil Suitability and management for crop productionThese 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 soilsIn 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 soilAgronomic 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

Soil Suitability and management for crop productionLaterite 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.

Soil Suitability and management for crop productionSalt 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.

Assessment1.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)

Assessment5.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. Saltaffected 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

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2.Soil Suitability for Crop Pdn (1)

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