sandy soil management

8/3/2019 Sandy Soil Management

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Sandy soil ManagementIntroduction

Sandy soils are characterized by less than 18% clay and more than

65% sand in the first 100 cm of the solum. The sand ground include all

soils in which the sand separate make up at least 70% and clay separate

15% or less of the material by weight. The soils having 70 to 90 per cent of

sand are termed as excessively permeable and coarse textured soils. The

agricultural productivity of sandy soils is low due to high water and nutrient

losses from root zone during rainy season or under heavy irrigation. The

coarse textured soils are not totally undesirable as they also have some

desirable properties of good drainage and aeration to crop plants.

Sandy soil charactersSandy soils are weakly developed soils with weak profile horizon

formation due slow chemical weathering. Physical weathering

predominates in response to extreme variations in temperature.

• Sand grains may be rounded or irregular depending on the amount of

abrasion they have undergone.

• Unless coated with clay and silt, sand particles are not sticky and

cannot be molded and are non plastic.

• Water holding capacity of sand grains is low because of the large

spaces between the separate, particles which promote rapid movement of

air and water.

• They have good drainage and aeration but may be drought prone.

• The hydraulic conductivity of sandy soil ranges from 5.2 to 9.5 m d-1.

• The surface area occupied by a gram of the sand is 0.1 m2 .

o Soil structure is very weak and unstable.

Management of physical problems of sandy soil

The different technologies can be grouped into

1. Enhancing moisture retention

2. Minimising percolation losses of water

3. Erosion control measures



Enchancing moisture retention

Being a coarse textured soil with very high amount of sand and much

less of clay and silt, efforts were made to increase the water retentivity of

soils by following different techniques.

a. Mulching

The naturally available waste materials can be spread over the soil

surface between the rows and crop plants in the cropped field based on its

availability. Approximately the requirement of these materials is 10 to 15 t

ha-1 for preventing the evaporative loss of water.

In case of synthetic mulching materials, the black and thick polythene

sheets are spread over the soil surface between the rows and crop plants,

leaving gaps for the plant hills or stems alone. Due to wind erosion fine

sand and silt particles brought from the neighbouring area and deposited

over sandy soils might be minimized the evaporation.

b. Clay incorporation

In the coarse textured soils, addition of sufficient amounts of fine soil

material like tank silt (pond sediments) or fine textured black soil, increases

the moisture retentivity of soil and thereby resulting higher yield of crops.

Such practice of increasing the fineness of texture in coarse textured soil is

a permanent improvement when compared to organic amendments.

Further addition of bentonite clay @ 2.5-3.0 kg / m trench in sandy soil had

resulted in significant enhancement of water retention

c. Organic wastes incorporation

Different organic amendments (carbonaceous waste materials from

the byproducts of industries and farms) have been used to improve the

water retentivity of sandy soils. Eventhough, they are having slow rate of

decomposition in soil, used as soil amendment to improve physical

condition of the soil.

In coarse textured soil, coir pith plays a vital role not only to reduce

water requirement for the crop but also to raise the crop yield. The

reduction in bulk density and hydraulic conductivity of soil has made



favourable physical condition by enabling roots proliferation due to

buoyancy of soil created by organic waste and increase the yield.

II. Minimizing percolation losses of water

In coarse textured soil, excessive permeability leads to enormous

wastage of water and it will be a major limitation in these soils especially

when scarcity of water prone tracts. With the availability of limited

quantity of water, adequate attention are needed to minimize the

excessive percolation loss and make the best use of water to get

satisfactory returns from crops.

a. Use of barrier in sub soil

A thin layer of 1 cm thick asphalt had been used as a barrier in sub-

surface (at about 25 cm from soil surface) of sandy soil for protecting the

properties of ground water and enhancing the productivity of land

b. Compaction techniques

Percolation losses in sandy soils are mainly due to the high porous

and excessively permeable nature. Under such conditions compaction

resulted the following beneficial results.

1. Reducing infiltration

2. Reduces time taken for each irrigation

3. Reduces water requirement of crops

4. Controls soil erosion

5. Retains more moisture at sowing time

6. Improves effectiveness of added fertilizers

7. Increases nutrient uptake

8. Ultimately increases yield potential of crops

While compacting the sandy soils the following points are

considered .

a) Compaction should be done at proper moisture only and sub-soil has

to be compacted for better nutrient and moisture retention.

b) Compaction once in two years is sufficient since the effect of

compaction persists for two years



c) After compaction, the top soil should be manipulated for better

seedling emergence and crop stand.

III. Erosion control measures

In arid and semi arid regions (more susceptible to wind erosion than

water erosion) having sandy soils are loaded with lot of fine sand and silt

particles when high velocity of wind occurs and deposited in the adjoining

lands. Thus, wind erosion causes severe damages to the health of soil and

crop environment. Unless such erosions are controlled, fertile and

productive lands may be affected.

a. Land levelling

When there is more slope, the condition favourable for facilitating

surface runoff of soil along with rain water. The sloppy nature is nullified by

forming normal gentle slope or near flat land surface, the surface runoff will

be minimized and consequently infiltration rate of water will increase,

leading to higher moisture storage possibility in subsoil.

b. Tillage

A major advantage of zero and minimum tillage techniques is used to

leave crop residues on soil to protect from the impact of direct rainfall. It

prevents the dispersion of soil material from aggregates and maintains the

infiltration capacity of soil consequently minimize soil erosion problems.

c.Gravel Layers

Placement of gravel layers on the surface or within the topsoil

decreases evaporative water losses by disrupting the capillary flow. It also

help them to retain more water than uniform soil, when water is initially

applied because water does not move through gravel until the soil above

has reached saturation.

d. Pasture developments (or grass cover or vegetative canopy

development)

Grass cover or pasture developments prevented surface soil getting

lifted by direct wind or rainwater. The grasses with fibrous root system will

bind the loose soil into aggregates and minimize the erodibility of land.



e. Wind belt and fuel wood plantations

In order to minimize the velocity of wind in sandy tracts,

establishment of wind belt with short shrubs and tall trees alternatively in

strips is very much beneficial and profitable. Windbreaks and shelterbelts

can effectively reduce wind velocity by 60 to 80%.

f. Surface mulch

Spreading of organic and inorganic wastes on the sandy soils will

prevent not only evaporation loss of soil moisture but also minimize wind

action. Mulches can be plastic film, woven plastic geotextiles, or layers of

organic refuse spread over the soil surface. Any material can be used as

mulch around plants if allows air and water to penetrate through the soil.

g. Use of Dry Vegetation as Vertical Hedges

In dry vegetation (Imperata cylindrica, Aristide pungens, Artemisia

herba alba, Retama raetam) or palm fronds are buried, preferably in moist

trenches to a depth of 15 cm, leaving about 35 cm extended above the

surface as a conventional method.

l. Use of Artificial Surface Sealants

Petroleum, synthetic rubber, chemicals and water soluble plastics are

examples of new products which have been recently used in dune and drift

sand stabilization. Spraying synthetic rubber latex and synthetic resins

were form an aggregated surface for establish vegetative cover.

Management of chemical problems of sandy soils

The management aspects of soil chemical problems associated with

these soils can be grouped into the following categories.

1. Improvement of nutrient retention and enhancing CEC in sandy soils

a) Clay incorporationb) Incorporation of organic matter

2. Fertility improvement

a) Major nutrients

b) Micronutrients

c) Slow release fertilizers



d) Split application

e) Irrigation Management

f) Crop rotation and cropping sequence

3. Salt affected sandy soil improvement

a) Leaching with good quality irrigation water

b) Amending with gypsum for alkali soils

c) Improvement of drainage facility and lowering water table of groundwater

d) Salt resistant crop varieties

1. Enhancing CEC of soil

a. Clay incorporation

In coarse textured soil, addition of clay can be improved the nutrient

retention and CEC (

b. Incorporation of organic matter

The organic waste like coir-pith, oil cake, farm waste, crop residues,

FYM, etc., are having very highly beneficial effect on nutrient retention

power in sandy soil. During the breakdown of organic matter by

microorganisms, compounds that are formed such as gums, waxes, and

resins will help to bind soil particles together as granules or aggregates. A

well-aggregated soil has high water infiltration rate.2. Soil fertility improvements

a. Major nutrients

Sandy soils are generally poor in almost all the nutrients. The rapid

losses of nutrients due to leaching in excessively permeable sandy soils, it

is essential for split application of nutrients.

i. Nitrogen

Nitrogen fertilizers can be applied in more number of splits thanpracticed for normal soil conditions. Among the nitrogenous fertilizers,

ammonium sulphate was most preferable due more retention of NH4+ form

in addition to supply of sulphur nutrient to the crop under sandy soil

condition .To decrease the loss of N by leaching the suggested practices

are



ii. Phosphorus

Good soil management which leads to an increase in fine fraction and

application of organic manures would tend to increase the phosphorus

content and soil fertility. Phosphorus is usually immobilized in soil due to

low content of clay and organic fractions in sandy soils.

iii. Potassium

Split application of potassium fertilizers to increase the K use

efficiency in sandy soil.

b. Micronutrients

Sandy soils are poor in micronutrients. Iron, manganese and zinc

deficiencies are noticeable on sandy soils. Foliar spraying with these

elements is commonly recommended. The use of chelating agents will also

help to improve the micronutrient use efficiency.

c. Slow release fertilizers

The use slow release nitrogenous fertilizers such as neem coated

urea, urea super granules, thiourea etc will improve the N use efficiency in

sandy soil. The local conditions is very important for highly permeable soil

in order to avoid leaching losses and provides sustained availability of N to

crop throughout its growth phase.

d. Water management by different irrigation methods

1. Sprinkler Irrigation

Sprinkler irrigation ensures correct depth of water applied and

resulting uniform distribution. Sprinkler irrigation has inherent features and

it well adapted to sandy soils. The water losses are low due to transport of

water by pressure pipes.

2. Drip Irrigation

Drip irrigation is the latest irrigation methods and it has the

advantages viz., water saving, higher yields, utilization of brackish waters,

manual labour extremely reduced, decreases in diseases, weed control etc.

f. Placement of an Asphalt Barrier



The rapid percolation of water through sandy soils, coupled with low

water retention capacity is being limiting factor for profitable use of sandy

soils. Asphalt barriers are economically feasible because they are long term

investment In sandy soil, provision barriers not only save irrigation water,

produces higher yields but also provide the possibility of more efficient

furrow irrigation.

3. Application of amendments

Application lime material to acid sandy soil (pH 6.2), which is

essential for successful establishment of alfalfa on either dryland, or

irrigated sandy soils. The rate of change in soil pH brought about by liming

depends on the fineness of limestone material applied. All liming materials

should be broadcasted and incorporated before the alfalfa is seeded.

Improvement of salt affected sandy soil

Generally sandy soils occupying normal type of relief and are non-

saline and non-alkaline. Under high rainfall conditions, these soils are acidic

because of washing down of all the bases. On the contrary coarse textured

soils of sea coastal zones are commonly saline and alkaline with varying

degree of hazards.

Casuarina and palmyrah are efficiently resistant to salinity-alkalinity

in sandy soil condition. Among the field crops fingermillet, chillies, cotton

and jasmine gave better performance in coastal Ramnad district of Tamil

Nadu. The green leaf manuring crops, Cassia auriculata comes up very

well. Tephrosea purpurea is a good performing self-sown green manure

crop in sandy soil.

a. Soil reclamation

Since theri soil is very coarse, with low water-retention qualities and

reclamation measures widely based on available local resources and cost-

effective. The green leaves are used for reclamation of theri lands but it is

very difficult to supply sufficiently large amounts of green leaves.

b. Concrete cultivation



In this method, the top oil is removed to a certain depth, depending

on the root system of the crop, a layer of cement mortar is poured on and

topsoil is replaced. The idea is to prevent water loss through percolation.

This method is costlier one.

c. Tank silt application

The applications of tank silt @ 20 lorry loads (about 200 tonnes) per

acre and followed by five lorry loads per year for the next few years will

improve the soil condition suitable for many crops. It is the cheapest and

best method and recommended for management of sandy soil by

agricultural department.

d. Suitable crops for theri lands

The indigenous drought-resistant tree species were palmyra

(Borassus flabellifer ), odai ( Acacia planifrons), tamarind (Tamarindus

indica) and neem ( Azadirachta indica) are better suited to theri conditions,

but are less profitable. The crops like coconut and drumstick are also

suitable for theri lands.

Recent technologies for management of sandy soil.

1. Application of Brown coal

Organic-mineral preparation using with brown coal remarkably

influenced the improvement of physical and water properties of arable

layer of sandy soil. The influence was either direct or indirect. The direct

impact was resulted from its chemical composition, which is the content of

nutrients and humic acids, whereas indirect impact was caused by

structure of the preparation, especially by strongly developed porosity

system. Changes of these properties depend upon the quality of applied

brown coal and when applying 160 tons ha-1 it was higher.

2. Application of distillery Effluent

The distillery effluent is a liquid waste obtained from distillery

industry contains large quantities of soluble organic matter and plant

nutrients. It does not contain any toxic elements / compounds.



The results of the post harvest soil analysis indicated that application

of distillery effluent until @ 5 lake litres ha-1 significantly improved the

physical properties of soil by reducing the bulk density and increasing the

water holding capacity and also increased the organic carbon,

exchangeable Ca, Mg and Na as given in table.30.

3. Improvement of Sandy Soil by Vetiver Grass Mulching andCompost

Due to the deep and dense roots system of vetiver grass widely

adopted for conservation sandy soil.

Technique for Greening of Sandy Soil

The technique

It consists of

a. Leaking water prevention technique.

b. Water evaporation prevention technique.

c. Water reserving technique of plant roots.

d. Manipulation in plant population.

sandy soil management

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