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IN-SITU MOISTURE

CONSERVATION PRINCIPLE AND

PRACTICES

Manikandan.VBte-08-027

Present by

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Dryland Agriculture:-

- In-situ moisture conservation

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In-situ conservation

The contour cultivation is the simplest method of in-situ conservation where each furrow will act as miniature reservoir to hold rain water.

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IN-SITU MOISTURE CONSERVATION TECHNIQUES

1) Micro catchments.2) Broad beds and furrows.3) Contour bund

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Micro catchments

-It is useful for insitu moisture conservation and erosion control for tree crops.

-Micro catchments used for sloping lands.

-Micro watershed (100 to 1000 Hect)

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Micro catchments

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Micro catchments

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Micro catchments

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Micro catchments FunctionsTo conserve insitu moisture and reduce soil

loss.

Circular basin of one meter diameter for

level lands depending upon infiltration and

rainfall.

‘ V’ ditches of size 5m x 5m with trees

planted centre and height according to the

rainfall and slope of slopy lands.

Saucer basins / semi circular bunds with 2m

diameter to a height of 15-20cm across the

slope.

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General information

Technique

Storage capacityper unit 

(m3)

Annual run-off contribution to soil moisture Additional water stored per ha

(m3)

Estimated surface Run-off control

(%)

Triangular catchments (V-Bunds)

13 5200 80

Crescent bunds 10.2 4080 73

Technique Cost/ha (Rs.)Triangular catchments (V-

Bunds) 6000-7000

Crescent bunds 2500-3000

Cost :-

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Salient features Slope ranges from 2 –8% Soil type – Light to moderate texture Insitu moisture conservation with

staggered planting Suitable for dry land Horticulture &

Agroforestry Bund height – 30 to 45 cm.

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Broad beds and Furrows

The broad bed and furrow system combines an element of erosion control with surface drainage.

Normal bed width adopted is 150 cm with 30 cm wide furrows at the end of the beds.

The broad beds and furrows have been found to be suitable for managing the deep black soils in India where surface drainage during the monsoon period is a problem.

In INDIA where surface drainage during the monsoon period is a problem.

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Cont..

The beds function as mini bunds at a grade and they help in reducing the velocity of surface runoff and increase the infiltration opportunity time. The excess water is removed through the furrows.

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Bed and furrow system

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Bed and furrow system

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Broad beds and FurrowsFunction :

To control erosion and to conserve soil moisture in the soil   during rainy days  

General information

: The broad bed and furrow system is laid within the field boundaries. The land levels taken and it is laid using either animal drawn or tractor drawn ridgers.  

Cost : Approximate cost for laying beds and furrows is Rs. 1000/- per ha.  

Salient features

: Conserves soil moisture in drylandControls sol erosion.Acts as a drainage channel during heavy rainy days.

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Contour bund Contour bunding is the construction of small

bund across the slope of the land on a contour so that the long slope is cut into a series of small ones and each contour bund acts as a barrier to the flow of water, thus making the water to walk rather than run, at the same time impounding water against it for increasing soil moisture.

Contour bunds divide the length of the slope, reduce the volume of runoff water, and thus preventing or minimizing the soil erosion

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Cont..

Contour bunds are constructed in relatively low rainfall areas, having an annual rainfall of less than 600 mm, particularly in areas having light textured soils.

For rolling and flatter lands having slopes from 2 to 6% contour bunding is practiced, in red soils.

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Contour bund

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Contour bundSource: http://terra-agro.com/Company/bhj/images/wasteland1.jpg

Click icon to add picture

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Contour bund

Function : To intercept the runoff flowing down the slope by an embankment.

General information

: It helps to control runoff velocity. The embankment may be closed or open, surplus arrangements are provided whenever necessary.

Cost : Approximate cost for laying contour bund is Rs. 1500/- per ha.

Salient features

: It can be adopted in light and medium textured soils.It can be laid upto 6% slopes.It helps to retain moisture in the field.

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Design parameters for contour bunds

RAMSER’S FORMULA:

V.I. = [(S/a) + b] x 0.3

where,V.I. = Vertical interval, mS = Slope of the field, %,a & b = Constantsa = 3 for medium and heavy

rainfall zones = 2 for low rain fall zonesb = 2

Horizontal interval (H.I.) = 100 x V.I./ S

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Length of contour bund / ha = = 100 x

30 % total length is added for Lateral and side

bunds

Total volume of earth work = 1.3 x 100 x xA

Total area lost/ha due to bunding = 1.3 x 100 x x

W

Where,

A = Area of cross section of the bund, m2

W = Bottom width of the bund, m

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Depth of water impounding

on the u/s of bund

Where,

RF = Maximum rain fall in mm

The height of the bund = 1.2 h including

20% free

board.

= h = √ (V.I.)(RF)/500}

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Specification for bund cross section

 Depth of soil (m)

Base width (m)

Top width (m)

Height (m)

Side slope (m)

Area cross section (sq.m)

Shallow soils

(7.5 – 22.5 cm)

2.67 0.38 0.75 1.5 : 1 1.14

Medium soil(22.5 – 45

cm)

3.12 0.60 0.85 1.5 : 1 1.56

Medium deep soils

4.25 0.60 0.90 2 : 1 2.18

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Situations for various bunding options

Bunding options

Soil type Rainfall (mm)

Slope (%)

Contour bund

Light soil <600 >1.5

Graded bund

All soils >600 1.5

Bench terraces

Deep soil >1000 6.0

Graded boarder strip

Deep alfisol and related

red soil

>800 >1.5

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In-Situ Moisture Conservation Techniques

Soil Type

Rainfall In-Situ Moisture Conservation Techniques

Red soil

Low Dead furrow at 3-6 m interval

  Medium Sowing on flat bed and riding later with eventual cultivation

  High Graded border strips

Black soil

Low Contour cultivation

  Medium Dead furrows at 3-6 m interval

  High Graded open furrow (0.2 to 0.3 m3) at 10 m interval across the slope

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IMPROVING SOIL MOISTURE STORAGE

Addition of silt, clay, organic matter etc., Increases field capacity and also raises wilting point to marginal increase in available moisture holding capacity.

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Reference:-http://

agritech.tnau.ac.in/agriculture/agri_majorareas_watershed_watershedmgt.html

http://dolr.nic.in/dpap.htm

http://agricoop.nic.in/guide.htm

http://dolr.nic.in/iwdp1.htm

http://agri.ap.nic.in/rvp.html

Thank you