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Presented by:
Presented to:
Flow of Presentation
1.
• Intoduction
2.
• Different mechanical measures
3.
• Research evidences
4
• Conclusion
Mechanical measures of soil
conservation
 The mechanical measures of soil conservation
include various engineering techniques and
structures which are adopted to supplement the
biological methods when the latter alone are not
sufficiently effective.
 These are also called as engineering measures.
 These practices aim at the following objectives:
1. To reduce the velocity of run-off water and to
retain it for long period so as to allow
maximum water to be absorbed and held in
the soil.
2. To divide a long slope into several small parts
so as to reduce the velocity of run-off water to
the minimum, and
Different Mechanical/Engineering
Measures
 BBF
 Contour bunding
 Graded bunding
 Contour trenches
 Contour stone wall
 Compartmental
bunding
 Random tied ridging
 Basin listing
 Bench terracing
 Micro catchment
 Farm ponds
 Percolation ponds
 Check dams
Based on the slope, some important conservation
practices
Conservation practice Slope
Contour bunding Upto 6%
Graded bunding 6-10%
Graded trenches 10-16%
Bench terracing 16-33%
Broad Beds and Furrows
(BBF)
• In a broadbed-and-furrow system, runoff water is
diverted into field furrows (30 cm wide and 30 cm deep).
• The field furrows are blocked at the lower end.
• When one furrow is full, the water backs up into the head
furrow and flows into the next field furrow.
• Between the field furrows are broad beds about 170 cm
wide, where crops are grown.
 It is suitable when the slope of the land is < 3%
 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.
Functions
 Conserves soil moisture in dryland
 Controls soil erosion.
 Acts as a drainage channel during heavy rainy
days.
General information
Broad Beds and Furrows (BBF)
(Source:
tnauagritech)
Contour Bunding
Function
 To intercept the runoff flowing down the slope
by an embankment.
 It helps to control runoff velocity.
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.
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
Bunding options Soil type Rainfall (mm)
Contour bund Light soil <600
Graded bund All soils <600
Bench terraces Deep soil >1000
Graded border
strip
Deep Alfisol and related
red soil
>800
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
Contour bunding
(Source:
Prepmate)
(Source:
tnauagritech)
Graded bunding
 In situations where the rain water is not readily
absorbed either de to high rainfall or low intake
in soil, graded bunding is recommended.
 Spaced at the same interval as contour bunds.
 The cross-section and grade of channel are
designed for conveying the peak rate of inter-
bunded runoff at non-scouring and siting
velocity.
Graded bunding
Contour trenches and staggered
trenches
 It was suitable where slope of the land is >
33.33%
 Dimension of trenches- 2 x 1 x 1 m3
 Trenches are excavated in contours and
excavated soil was used to form bunds in the
down line.
 The trenches were formed in 5 to 10 feet
vertical distance.
 It helps to reduce velocity of water.
 It checks soil erosion.
Contour trenches
(Source: RAO)
Contour stone wall
 Contour stone wall is constructed where the slope
is > 15 to < 30% under the guidance of engineers .
 In case of highly hill areas, contour trenches were
constructed along with stone wall.
 It is suitable for shallow and gravel soil.
 It is recommended where difficult to construct
bench terrace.
 It helps in land preparation and checks soil
erosion.
Note : If the length of the contour stone wall is more
than 800 feet, the excess water flow could be
guided through contours with proper outlets.
Contour stone wall
(Source: tnauagritech) (Source: Roy &
Indranil,2009)
Compartmental bunding
 Compartmental bunding means the entire field is
divided into small compartments with pre
determined size to retain the rain water where it
falls and arrest soil erosion.
 The compartmental bunds are formed using
bund former.
 The size of the bunds depends upon slope of the
land.
 Compartmental bunds provide more opportunity
time for water to infiltrate into the soil and help in
conserving soil moisture.
Salient features :
 Compartmental bunding is an effective moisture
conservation measure in dryland.
 It is suitable for lesser rrainfall areas and the slope
is < 1%
 The lands are divided into small compartments
with the dimension of 8 x 5 m2.
 Small compartments act as a dam and store the
rainfall received in the compartments for longer
period.
 It increases water holding capacity of the soil.
 It can be formed while ploughing itself or before
early sowing.
 Reduces the formation of cracks.
 It will overcome the disadvantages of contour
Compartmental bunding
(Source: Patil et al., 2015
Random Tied ridging
 The ridges are vertically tied at shorter interval to
create rectangular water harvesting structures.
During heavy rainy season it facilitates to infiltrate
water to the soil.
 The slight sloppiness in the tied ridges facilitates
draining of excess water infiltrate into the soil.
 Summer ploughing, broad bed and furrows, ridges
and furrows, random tie ridging, compartmental .
 bunding etc. are the various in situ water
harvesting methods for black and red soils cause
an increase of up to 15 per cent in crop yields.
 It conserves soil and moisture in redsoils.
Tied ridging
(Source: Panyan et al.,
2015)
Basin listing
 In this method of soil and water conservation
basins are constructed using a special implement
called basin-lister. These basins are constructed
across the slope. Basin listing provides maximum
time to rain water for infiltration into the soil.
Bench terracing
 On steeply sloping lands, the slopes where such
terraces are found useful vary from 16 to 33 per
cent.
 Bench terraces with 100 m length, longitudinal
grades in the range of 0.2 to 0.8 per cent are
recommended for Alfisols of high rainfall regions.
 Bench terraces are suitable where soil depth is more
than 21/2 feet and it can be laid in slopy land ranges
from 16.67 to 33%.
 In highly slopy lands (8-15%) three types of bench
terraces are planned viz., horizontal, inward and outward
based on soil type and water holding capacity.
 In hilly areas, cultivation of horticultural crops under
bench terracing method conserve soil, moisture and
reduces nutrient loss and increases the yield.
 It also reduces soil erosion.
Note: If the length of the Bench Terraces is more than 400
feet, the excess water flow could be guided through
contours with proper outlets.
Basin listing
(Source: Arizona memory
project)
(Source: Library of congress)
Bench terracing
(Source:
FAO)
(Source: tnauagritech)
Micro Catchment
 In drylands, quantum of rainfall is not sufficient for the
cultivation of crops , if tree cultivation is possible
means developing micro catchments around the tree
will improve the storage of rainfall and increase the
yield. In slopy land this type of catchments could be
developed across the slope.
For tree crops, according to inter space available
catchments are formed. It stores rain water where it
falls and helps in growth of trees. For plain and hill
areas the shape of the bunds were decided.
Micro catchments size of 5 x 5 m and the quantum of
rainfall is 20 mm will give 500 liters of water.
Circular and semicircular basins
 It is suitable for fruit crops.
 Bundings were for formed individually for each tree.
 Circular bunding recommended for plain land area,
whereas sloppy lands with semicircular or crescent
bunding.
 Distance between bunding depends upon tree spacing
'V' ditches
 In the land areas at 4 to 6 m intervals V shaped ditches
are formed with the help of machine or animal drawn
machine. Down the line of ditches covered with soil
bunding and the trees are planted in the pits based on
the spacing needed.
Micro catchments
(Source: Das&Bandhopadhay, 2013) (Source:
FAO)
Farm ponds
 Farm ponds are small water bodies formed either
by the construction of a small dam or
embankment across a waterway or by excavating
or dug out. The water is usually harvested from a
small catchment area and then used for irrigation
during prolonged periods
Specifications:
 In the selected farm land the farm pond dimension
of 8m x 8m x 1.5m can be constructed for the
every 1 or 2 ha of land area.
Water
spreading area
(sq.m)
Depth of water (m) Suitable uses
2000 to 10000 2.5 - 3.0
Irrigation, fisheries and
drinking water
2000 to <
10000
1.5 – 2.5
Irrigation & drinking
water
< 2000 1.5-2.5
Pot irrigation for trees
and drinking water
Benefits of farm ponds :
•It collects excess runoff during rainy period.
•Stored water can be used for supplemental irrigation to crops.
•It is useful as drinking water for cattles during drought
situation.
•It can be used for spraying pesticides.
•It conserves soil and moisture.
1 Bottom Area 20 m x 20 m
2 Top Area 35 m X 35 m
3 Depth 2.2 m
4 Cost of lining material (Rs) 85,000
5 Excavation (Rs) 20,000
6 Coir dust & spreading (Rs) 2,000
7
Spreading plastic lining and sheet
welding (Rs) and with earth cover
27,000
8 Cost of inlet and outlet structures 66,000
9 Total cost (Rs) 2,00,000
Farm pond
Source:
Krishijagran)
(Source: tnauagritech
Percolation ponds
 Percolation ponds are small ponds located
mostly in low lying areas of public lands and
formed in order to store the run-off of rainwater
and to allow it to percolate downwards and
sideways.
 Deep ponds are preferred since evaporation of
the stored water therein will be less.
 It has been observed that the percolation ponds
are effective up to a distance of 1000 metres on
the downstream side and wells within this range
are benefited with more replenishment of water.
Benefits :
 It replenish ground water during rainy season .
 It reduces velocity of water thereby reduce soil erosion.
 Reduces siltation in water tank, ponds and check dams.
 Floods can be avoided.
 Generates employment during dry period.
 Increased cultivable area.
 Points to be considered.
 Area should't be hard and rocky.
 Capacity of the ponds depends upon amount and frequency
of water flow.
 In the downstream there should be farm lands and irrigation
well.
 The depth should be atleast 1.5 m.
 The depth should be atleast 1.5 m.
 Strengthen the bunds with soil .
Percolation pond
(Gale, 2005)
Gully Control Measures
Temporary Gully Control Structures
(TGCS)
• TGCS have a life span of 3 to 8 years and they
are pretty effective where the amount of runoff
is not too large.
• These are made of locally available materials.
• Basic purposes they serve are to retain more
water as well as soil for proper plant growth
and prevent channel erosion until sufficient
vegetation is established on the upstream side
 TGCS are of many types:
1. Woven wire check dams
2. Brush dams
3. Loose rock dams
4. Plan or slab dams
5. Log check dams
6. Boulder check dams
7. Gabion
Design Criteria of TGCS
• The overall height of a temporary check shouldn’t
ordinarily be more than 75 cm. An effective height of
about 30 cm is usually considered sufficient. Also,
sufficient freeboard is necessary.
• Life of the check dams under ordinary conditions
should be in between 3 to 8 years.
• Spillway capacity of check dams is generally designed
to handle peak runoff that may be expected once in 5
to 10 year return period.
• Since the purpose of check dams in gully control is to
eliminate grade in the channel, check dams
theoretically should be spaced in such a way that the
crest elevation of one will be same as the bottom
elevation of the adjacent dam up-stream.
Woven Wire Check Dams
• Woven-wire check dams are small barriers which
are usually constructed to hold fine material in the
gully.
• Used in gullies of moderate slopes (not more than
10 percent) and small drainage areas that do not
have flood flows which carry rocks and boulders.
• Help in the establishment of vegetation for
permanent control of erosion.
• Dam is built in half-moon shape with the open end
up-stream.
• To construct a woven-wire dam, a row of posts is
set along the curve of the proposed dam at about
1.2 m intervals and 60-90 cm deep.
• Heavy gauge woven wire is placed against the
post with the lower part set in a trench (15- 20
cm deep), and 25-30 cm projected above the
ground surface along the spillway width.
• Rock, brush or sod may be placed
approximately up to a length of 1.2 m to form
the apron.
• For sealing the structure, straw, fine brush or
similar material should be placed against the
wire on the upstream side upto the height of
spillway.
Woven wire check dams
(Source: Agr. Handbook No. 61. USDA, SCS
Woven wire check dams
Brush Dams
 • Cheap and easy to build, but least stable of all
types of check dams.
 • Best suited for gullies with small drainage area.
 • Centre of the dam is kept lower than the ends to
allow water to flow over the dam rather than
around it.
 • For a distance of 3 to 4.5 m along the site of the
structure, sides and bottom of the gully are
covered with thin layer of straw or similar fine
mulch.
 • Brushes are then packed closely together over
the mulch to about one half of the proposed height
• Heavy galvanized wire is used to fasten the
stakes in a row, as well as to firmly compress
the brushes in places.
• Sometimes large stones are also placed on top
of brush to keep it compressed and in close
contact with the bottom of the gully.
• Major weakness is the difficulty of preventing
the leaks and constant attention is required to
plug openings of appropriate size with straw as
they develop.
Brush dam
(Source: Agr. Handbook No. 61. USDA, SCS
Brush dam
Loose Rock Dams
• Loose rock dams made of relatively small rocks
are placed across the gully. The main objectives
for these dams are to control channel erosion
along the gully bed, and to stop waterfall erosion
by stabilizing gully heads.
• Loose stone check dams are used to stabilize the
small gullies.
• The length of the gully channel is not more than
100 m and the gully catchment area is 2 ha or
less. • These dams can be used in all regions.
• Used in areas where stones or rocks of
appreciable size and suitable quality are available.
• Flat stones are the best choice for dam making. •
Stones can be laid in such a way that the entire
structure is keyed together.
• A trench is made across the gully to a depth of
about 30 cm. This forms the base of the dam on
which the stones are laid in rows and are brought
to the required height.
• The centre of the dam is kept lower than the sides
to form spillway.
• To serve as an apron, several large flat rocks may
be countersunk below the spillway, extending
about 1 m down-stream from the base of the dam.
Loose Rock Dams
(Source: Agr. Handbook No. 61. USDA, SCS
Loose Rock Dams
Log Check Dam
• They are similar to plank or slab dams. Logs and
posts used for the construction are placed across
the gully. • They can also be built of planks, heavy
boards, slabs, poles or old railroad ties.
• The main objectives of log check dams are to hold
fine and coarse material carried by flowing water in
the gully, and to stabilize gully heads.
• They are used to stabilize incipient, small and
branch gullies generally not longer than 100 m and
with catchment areas of less than 2 hectares.
• The maximum height of the dam is 1.5 m from the
ground level. Both, its downstream and upstream
face inclination are 25 percent backwards.
Log Check Dam
Log Check Dam
Boulder Check Dams
• Boulder check dams placed across the gully are
used mainly to control channel erosion and to
stabilize gully heads.
• In a gully system or multiple-gully system all the
main gully channels of continuous gullies (each
continuous gully has a catchment area of 20 ha or
less and its length is about 900 m) can be
stabilized by boulder check dams.
• These dams can be used in all regions.
• The maximum total height of the dam is 2 m.
Foundation depth must be at least half of the
effective height.
• The thickness of the dam at spillway level is 0.7 to
1.0 m (average 0.85 m), and the inclination of its
downstream face is 30 percent.
• The upstream face of the dam is usually vertical. If
the above-mentioned dimensions are used, it is
not necessary to test the stability of the dam
against overturning, collapsing and sliding.
• The dimensions of the spillway should be
computed according to the maximum discharge of
the gully catchment area.
• The form of the spillway is generally trapezoidal.
Boulder Check Dams
Boulder Check Dams
Sandbag Check-Dam
• Sandbag check-dams are made from used jute
or polyethylene bags (50 kg) filled with
soil/sand. • The bags are piled up to a
maximum of 3 – 4 layers to form a small check-
dam.
• This cheap technique is particularly useful in
areas with insufficient supply of stones for
building ordinary check-dams.
• By erecting sandbag dams large rills or small
gullies (finger gullies) can be controlled, while
they are not suitable for the treatment of large
gullies.
Sandbag Check-Dam
Gabion Check Dam
• If the catchment area of a gully is 20 ha or less and
the length of the gully is about 1 000 m, channel
erosion will be controlled by boulder check dams,
but the first check dam and its counter-dam should
be constructed as gabions.
• If the gully crosses a road, gabion check dams
may be built above and below the road at the
junction points.
• In addition, gabion check dams combined with
gabion retaining walls can be used to stabilize
landslides in the upper portions of the gully.
• Generally, it is neither necessary, nor economical
to build a series of gabion check dams to control
channel erosion along the gully beds.
Gabion Check Dam
Permanent Gully Control Structures
(PGCS)
• If the erosion control programmer requires bigger
structure, then PGCS are used.
• PGCS, built of masonry, reinforced concrete or earth
are efficient supplemental control measures in soil and
water conservation.
• They are helpful in situation where vegetative
measures or temporary structures fail to serve the
purpose of controlling the concentration of runoff or
reclaim a gully.
• PGCS are generally used in medium to large gullies
with medium to large drainage area.
• PGCS are designed to handle runoff from the heaviest
rains that may be expected once in 25 to 50 years or
more depending upon the estimated life of the
structure.
 Basic permanent structures, generally
employed in stabilizing gullies are:
➢Drop spillway
➢Drop-inlet spillway
➢Chute spillway
➢Permanent earthen check dams
Basic Components of PGCS
 These components can be divided into three
groups:
1. Inlet: Water enters the structures through the
inlet, which may be in the form of a box or weir in
a wall.
2. Conduit: The conduit receives the water from the
inlet and conducts it through the structure. It
restricts the water to a definite channel. The
conduit may be closed in the form of a box
channel or it may be open as in a rectangular
channel.
3. Outlet: Its function is to discharge the water into
the channel below at a safe velocity. The outlet
Drop Spillway
• It is a weir structure, in which flow passes through the
weir opening, fall or drops on an approximately level
apron or stilling basic and then passes into the
downstream channel.
• Its use is limited to a maximum drop of 3 m.
• It is mainly used at the gully bed to create a control
point.
• Several such drop structures are constructed across
the gully width throughout the length at fixed intervals.
• The series of such structures, develop a continuous
break to flow of water, causing deposition of sediments
and thus filling the gully section.
• Sometimes, the drop structures are also used at the
gully head to pass the flow safely and controlling the
Drop Spillway
Drop Spillway
Drop Inlet Spillway
• A drop inlet or shaft spillway is one in which the water
enters through a horizontally positioned circular or
rectangular box type riser or inlet and flows to some
type of outlet protection through a circular (horizontal
or near horizontal) conduit.
• The drop inlet spillway is ideally suited to conditions
when there is need to control the downstream channel
flow by providing a temporary storage upstream of the
structure.
• It consists of an earthen dam and a pipe spillway.
• The dam provides the temporary storage of runoff from
the contributing watershed while the spillway permits
the design discharge to pass downstream.
Drop Inlet Spillway
Drop Inlet Spillway
Chute Spillway
• Chute (open channel or trough) spillway is a spillway
whose discharge is conveyed from the upper reach of the
channel or a reservoir to the downstream channel level
through an open channel placed along a dam, abutment
(supporting wall), or through a saddle.
• Chute structures are useful for gully head control and they
could be used for drops upto 5 to 6 m.
• Chute spillways are constructed at the gully head to
convey the discharge from upstream area of gully into the
gully through a concrete or masonry open channel, when
drop height exceeds the economic limit of drop structures.
• Chute spillway has more advantage than a drop spillway,
when a large runoff volume is required to be discharged
from the area.
Chute Spillway
Chute Spillway
Earthen Dam
• An earthen embankment is a raised confining structure made
from compacted soil.
• The purpose of an earthen embankment is to confine and
divert the storm water runoff.
• It can also be used for increasing infiltration, detention and
retention facilities.
• Earthen embankments are generally trapezoidal in shape and
most simple and economic in nature.
• They are mainly built with clay, sand and gravel, hence they
are also known as earth fill dams or earthen dams.
• They are constructed where the foundation or the underlying
material or rocks are weak to support the masonry dam or
where the suitable competent rocks are at greater depth.
• They are relatively smaller in height and broader at the base.
Earthen Dam
(Source: Michael and Ojha, 2012)
Research Findings
Table 1. Yield of Cotton and Millet in farm fields
treated with and without Contour bunding
Technique
Crop species
Cotton
(kg ha-1)
Millet
grain (kg ha-1)
Contour bunding 1998 1322
No contour bunding 1617 * 890 **
* (p<0.05), ** (p<0.01)
(Traore et al., 2017)
(Southern Mali)
Figure 1. Millet field in southern Mali without
application of contour bunding (NCB) and with CB
NCB CB
(Traore et al., 2017)
(Southern Mali)
Table 2. Grain yield of crops in fields with and without
Contour Bunding.
Crop
Yield (kg ha−1) and WP (kg mm−1)
Bougouni district Koutiala district
NCB WP CB WP NCB WP CB WP
Sorghum 1292 2.11 1530* 2.50 1450 2.68 2120* 3.92
Maize 1360 2.22 2310** 3.78 1300 2.40 2020** 3.73
Millet 1370 2.24 2130** 3.48 1350 2.49 2720** 5.02
Groundn
ut
1180 1.93 1400* 2.29 1114 2.06 1920** 3.54
(WP refers to water productivity; CB refers to contour bunding; NCB refers to
no contour bunding.) *Statistically significant at P < 0.05, **Statistically
significant at P < 0.01.
(Birhanu, et al. 2019)
(Southern Mali)
Table 3. Runoff coefficient and soil loss in Bougouni and
Koutiala districts during 2016 and 2017 cropping season
Runoff coefficient (%) Soil loss kg ha−1 yr−1
Technique CB 19.25 b 4970 b
No CB 35.62 a 13090 a
P value 0.004 0.02
Site Koutiala 23.75 b 5733 b
Bougouni 31.12 a 11,332 a
P value 0.03 0.04
Year 2016 30.87 a 11,228 a
2017 24 b 5837 b
P value 0.05 0.04
(Note: values with different letters are statistically different at P = 0.05. Column
means represent runoff coefficient and soil loss; row values show technology,
experimental site andyear of data record.)
(Birhanu, et al. 2019)
(Southern Mali)
Table 4. Nutrient losses in eroded soil (kg ha−1 yr−1) under CB
and non CB in Bougouni and Koutiala districts during 2016
and 2017 cropping season.
Descriptio
n
C N P Ca Mg K
Technique CB 45b 5b 4b 5b 3b 4b
No CB 106a 11a 8a 9a 5a 7a
P value 0.04 0.006 0.02 0.01 0.01 0.02
Site Koutiala 75 7 4 8 4 5
Bougouni 76 8 6 7 4 6
P value 0.97 0.98 0.06 0.6 0.62 0.76
Year 2016 112a 10a 7a 10a 5a 7a
2017 39b 5b 4b 5b 3b 3b
P value 0.02 0.01 0.12 0.008 0.003 0.01
(Birhanu, et al. 2019)
(Southern Mali)
(Note: values with different letters are statistically different at P = 0.05.)
Table 5. Month wise LAI and canopy
interception for custard apple and atemoya
during 2013-14.
Plantatio
n
Month Leaf Area Index, LAI
Canopy Interception,
(mm)
CCT
Treated
catchment
Non
Treated
catchment
CCT
Treated
catchment
Non
Treated
catchment
Custar
d apple
June 0.26 0.22 0.01 0.01
July 0.27 0.23 0.01 0.01
August 0.55 0.49 0.03 0.02
Septemb
er
0.69 0.63 0.03 0.03
October 0.70 0.62 0.04 0.03
Novembe
r
0.66 0.57 0.03 0.03
Plantatio
n
Month Leaf Area Index, LAI Canopy Interception,
(mm)
CCT
Treated
catchment
Non
Treated
catchment
CCT
Treated
catchment
Non
Treated
catchment
Atemoya June 0.42 0.37 0.02 0.02
July 0.57 0.47 0.03 0.02
August 1.40 1.21 0.07 0.06
Septemb
er
1.91 1.61 0.10 0.08
October 1.86 1.33 0.09 0.07
Novembe
r
1.81 1.35 0.09 0.07
Decembe
r
1.28 1.09 0.06 0.05
(Patode et al., 2015)
(AICRPDA, Dr.PDKV,
Table 6: Crop growth and yield components of sunflower
as influenced by rainwater conservation and integrated
nutrient management practices at Research farm during
2008–09.
Treatments Plant height
(m)
Head weight
(g plant−1)
Stover yield
(kg ha−1)
Grain yield
(kg ha−1)
Rainwater conservation practices
Flat bed 130.7 36.28 1120 886
Compartmental
Bunding
144.7 48.47 1299 1079
Ridges and
Furrows
140.8 47.37 1298 1072
S.Em.± 1.8 1.77 110 30
LSD (p < 0.05) 5.6 5.58 ns 119
Integrated nutrient management
INM1 135.8 42.01 1128 954
INM2 138.3 44.07 1208 1011
INM3 142.1 46.05 1379 1071
S.Em.± 1.3 1.04 76 44
LSD (p < 0.05) 3.7 3.00 234 136
(Patil et al., 2015)
(Research farm, Bellary)
Table 7. Sediment losses on runoff plots as
influenced by soil conservation measures
Conservation
Measure
Soil loss (t/ha)
September - May November - May
Control, none 3.81a* 3.51a
Control, fertilizer 1.59b 1.33b
Bench terraces 1.13bc 0.68bc
Grass bunds 0.81bc 0.40c
Grass + Gliricidia
bunds & mulch
0.53c 0.34c
*Values followed by different letters are significantly different (p
< 0.05) using protected LSD analysis
(Stephen and Jill,
(Kerinci,
 Maharashtra has a rugged topography and basaltic geological
formation so there is limitation on canal as well as well irrigation. There
are many measures for the conservation of water and soil. They are
performed by various government agencies. See the following table
(Table 8)…..
Objective Types of Measures Agency
Water conservation Vanrai, Kaccha earthen,
Bund, Nala Bandhara,
Nala Plugs, check dam,
Percolation tank
Soil Conservation
Department
Soil Conservation Forestation, Continuous
contour trench
Forest Department &
Social Forestry
Contour trench,
Contour bonding, Farm
pond, Check dam
Soil Conservation
Department
Strengthening of
drinking water
sources
Fracture Seal
Cementation, Jacket
well, Stream blasting,
Bore Blast Technique,
Bore well flooding.
Groundwater Surveys &
Development Agency
(Nitin Bajirao, 2016)
(Maharashtra)
Table.9 Yield and Growth parameters of Mango
using Micro-catchments
Treatments No.
inflorescenc
e
/branch
No of fruit
set/
inflorescenc
e
Fruit yield
(Kg/tree)
T1-Half-moon 4.6 5.1 55.5
T2-Circle 3.9 4.0 50.3
T3-V-bund 4.4 4.6 53.0
T4-control 10.4 2.2 45.4
Cd 0.71 0.75 3.4
SEM 0.24 0.26 1.2
(Ali, 2017)
(Ramanagara, Karnataka)
Conclusion
 The purpose of mechanical soil conservation
measures is to protect the soil from the
impacts of heavy rain and wind and prevent
soil erosion.
 Mechanical measures usually involve
construction of mechanical barriers across the
direction of flow of rain water to retard or retain
runoff and thereby reduce soil and water loss.
 Different measures can be adopted based on
the different conditions and have a very
significant effect on the soil loss and yields.
MECHANICAL MEASURES OF SOIL CONSERVATION.pptx

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MECHANICAL MEASURES OF SOIL CONSERVATION.pptx

  • 3. Flow of Presentation 1. • Intoduction 2. • Different mechanical measures 3. • Research evidences 4 • Conclusion
  • 4. Mechanical measures of soil conservation  The mechanical measures of soil conservation include various engineering techniques and structures which are adopted to supplement the biological methods when the latter alone are not sufficiently effective.  These are also called as engineering measures.  These practices aim at the following objectives: 1. To reduce the velocity of run-off water and to retain it for long period so as to allow maximum water to be absorbed and held in the soil. 2. To divide a long slope into several small parts so as to reduce the velocity of run-off water to the minimum, and
  • 5. Different Mechanical/Engineering Measures  BBF  Contour bunding  Graded bunding  Contour trenches  Contour stone wall  Compartmental bunding  Random tied ridging  Basin listing  Bench terracing  Micro catchment  Farm ponds  Percolation ponds  Check dams
  • 6. Based on the slope, some important conservation practices Conservation practice Slope Contour bunding Upto 6% Graded bunding 6-10% Graded trenches 10-16% Bench terracing 16-33%
  • 7. Broad Beds and Furrows (BBF) • In a broadbed-and-furrow system, runoff water is diverted into field furrows (30 cm wide and 30 cm deep). • The field furrows are blocked at the lower end. • When one furrow is full, the water backs up into the head furrow and flows into the next field furrow. • Between the field furrows are broad beds about 170 cm wide, where crops are grown.
  • 8.  It is suitable when the slope of the land is < 3%  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. Functions  Conserves soil moisture in dryland  Controls soil erosion.  Acts as a drainage channel during heavy rainy days. General information
  • 9. Broad Beds and Furrows (BBF) (Source: tnauagritech)
  • 10. Contour Bunding Function  To intercept the runoff flowing down the slope by an embankment.  It helps to control runoff velocity. 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.
  • 11. 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
  • 12. Bunding options Soil type Rainfall (mm) Contour bund Light soil <600 Graded bund All soils <600 Bench terraces Deep soil >1000 Graded border strip Deep Alfisol and related red soil >800
  • 13. 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
  • 15. Graded bunding  In situations where the rain water is not readily absorbed either de to high rainfall or low intake in soil, graded bunding is recommended.  Spaced at the same interval as contour bunds.  The cross-section and grade of channel are designed for conveying the peak rate of inter- bunded runoff at non-scouring and siting velocity.
  • 17. Contour trenches and staggered trenches  It was suitable where slope of the land is > 33.33%  Dimension of trenches- 2 x 1 x 1 m3  Trenches are excavated in contours and excavated soil was used to form bunds in the down line.  The trenches were formed in 5 to 10 feet vertical distance.  It helps to reduce velocity of water.  It checks soil erosion.
  • 19. Contour stone wall  Contour stone wall is constructed where the slope is > 15 to < 30% under the guidance of engineers .  In case of highly hill areas, contour trenches were constructed along with stone wall.  It is suitable for shallow and gravel soil.  It is recommended where difficult to construct bench terrace.  It helps in land preparation and checks soil erosion. Note : If the length of the contour stone wall is more than 800 feet, the excess water flow could be guided through contours with proper outlets.
  • 20. Contour stone wall (Source: tnauagritech) (Source: Roy & Indranil,2009)
  • 21. Compartmental bunding  Compartmental bunding means the entire field is divided into small compartments with pre determined size to retain the rain water where it falls and arrest soil erosion.  The compartmental bunds are formed using bund former.  The size of the bunds depends upon slope of the land.  Compartmental bunds provide more opportunity time for water to infiltrate into the soil and help in conserving soil moisture.
  • 22. Salient features :  Compartmental bunding is an effective moisture conservation measure in dryland.  It is suitable for lesser rrainfall areas and the slope is < 1%  The lands are divided into small compartments with the dimension of 8 x 5 m2.  Small compartments act as a dam and store the rainfall received in the compartments for longer period.  It increases water holding capacity of the soil.  It can be formed while ploughing itself or before early sowing.  Reduces the formation of cracks.  It will overcome the disadvantages of contour
  • 24. Random Tied ridging  The ridges are vertically tied at shorter interval to create rectangular water harvesting structures. During heavy rainy season it facilitates to infiltrate water to the soil.  The slight sloppiness in the tied ridges facilitates draining of excess water infiltrate into the soil.  Summer ploughing, broad bed and furrows, ridges and furrows, random tie ridging, compartmental .  bunding etc. are the various in situ water harvesting methods for black and red soils cause an increase of up to 15 per cent in crop yields.  It conserves soil and moisture in redsoils.
  • 26. Basin listing  In this method of soil and water conservation basins are constructed using a special implement called basin-lister. These basins are constructed across the slope. Basin listing provides maximum time to rain water for infiltration into the soil. Bench terracing  On steeply sloping lands, the slopes where such terraces are found useful vary from 16 to 33 per cent.  Bench terraces with 100 m length, longitudinal grades in the range of 0.2 to 0.8 per cent are recommended for Alfisols of high rainfall regions.
  • 27.  Bench terraces are suitable where soil depth is more than 21/2 feet and it can be laid in slopy land ranges from 16.67 to 33%.  In highly slopy lands (8-15%) three types of bench terraces are planned viz., horizontal, inward and outward based on soil type and water holding capacity.  In hilly areas, cultivation of horticultural crops under bench terracing method conserve soil, moisture and reduces nutrient loss and increases the yield.  It also reduces soil erosion. Note: If the length of the Bench Terraces is more than 400 feet, the excess water flow could be guided through contours with proper outlets.
  • 28. Basin listing (Source: Arizona memory project) (Source: Library of congress)
  • 30. Micro Catchment  In drylands, quantum of rainfall is not sufficient for the cultivation of crops , if tree cultivation is possible means developing micro catchments around the tree will improve the storage of rainfall and increase the yield. In slopy land this type of catchments could be developed across the slope. For tree crops, according to inter space available catchments are formed. It stores rain water where it falls and helps in growth of trees. For plain and hill areas the shape of the bunds were decided. Micro catchments size of 5 x 5 m and the quantum of rainfall is 20 mm will give 500 liters of water.
  • 31. Circular and semicircular basins  It is suitable for fruit crops.  Bundings were for formed individually for each tree.  Circular bunding recommended for plain land area, whereas sloppy lands with semicircular or crescent bunding.  Distance between bunding depends upon tree spacing 'V' ditches  In the land areas at 4 to 6 m intervals V shaped ditches are formed with the help of machine or animal drawn machine. Down the line of ditches covered with soil bunding and the trees are planted in the pits based on the spacing needed.
  • 33. Farm ponds  Farm ponds are small water bodies formed either by the construction of a small dam or embankment across a waterway or by excavating or dug out. The water is usually harvested from a small catchment area and then used for irrigation during prolonged periods Specifications:  In the selected farm land the farm pond dimension of 8m x 8m x 1.5m can be constructed for the every 1 or 2 ha of land area.
  • 34. Water spreading area (sq.m) Depth of water (m) Suitable uses 2000 to 10000 2.5 - 3.0 Irrigation, fisheries and drinking water 2000 to < 10000 1.5 – 2.5 Irrigation & drinking water < 2000 1.5-2.5 Pot irrigation for trees and drinking water Benefits of farm ponds : •It collects excess runoff during rainy period. •Stored water can be used for supplemental irrigation to crops. •It is useful as drinking water for cattles during drought situation. •It can be used for spraying pesticides. •It conserves soil and moisture.
  • 35. 1 Bottom Area 20 m x 20 m 2 Top Area 35 m X 35 m 3 Depth 2.2 m 4 Cost of lining material (Rs) 85,000 5 Excavation (Rs) 20,000 6 Coir dust & spreading (Rs) 2,000 7 Spreading plastic lining and sheet welding (Rs) and with earth cover 27,000 8 Cost of inlet and outlet structures 66,000 9 Total cost (Rs) 2,00,000
  • 37. Percolation ponds  Percolation ponds are small ponds located mostly in low lying areas of public lands and formed in order to store the run-off of rainwater and to allow it to percolate downwards and sideways.  Deep ponds are preferred since evaporation of the stored water therein will be less.  It has been observed that the percolation ponds are effective up to a distance of 1000 metres on the downstream side and wells within this range are benefited with more replenishment of water.
  • 38. Benefits :  It replenish ground water during rainy season .  It reduces velocity of water thereby reduce soil erosion.  Reduces siltation in water tank, ponds and check dams.  Floods can be avoided.  Generates employment during dry period.  Increased cultivable area.  Points to be considered.  Area should't be hard and rocky.  Capacity of the ponds depends upon amount and frequency of water flow.  In the downstream there should be farm lands and irrigation well.  The depth should be atleast 1.5 m.  The depth should be atleast 1.5 m.  Strengthen the bunds with soil .
  • 40. Gully Control Measures Temporary Gully Control Structures (TGCS) • TGCS have a life span of 3 to 8 years and they are pretty effective where the amount of runoff is not too large. • These are made of locally available materials. • Basic purposes they serve are to retain more water as well as soil for proper plant growth and prevent channel erosion until sufficient vegetation is established on the upstream side
  • 41.  TGCS are of many types: 1. Woven wire check dams 2. Brush dams 3. Loose rock dams 4. Plan or slab dams 5. Log check dams 6. Boulder check dams 7. Gabion
  • 42. Design Criteria of TGCS • The overall height of a temporary check shouldn’t ordinarily be more than 75 cm. An effective height of about 30 cm is usually considered sufficient. Also, sufficient freeboard is necessary. • Life of the check dams under ordinary conditions should be in between 3 to 8 years. • Spillway capacity of check dams is generally designed to handle peak runoff that may be expected once in 5 to 10 year return period. • Since the purpose of check dams in gully control is to eliminate grade in the channel, check dams theoretically should be spaced in such a way that the crest elevation of one will be same as the bottom elevation of the adjacent dam up-stream.
  • 43. Woven Wire Check Dams • Woven-wire check dams are small barriers which are usually constructed to hold fine material in the gully. • Used in gullies of moderate slopes (not more than 10 percent) and small drainage areas that do not have flood flows which carry rocks and boulders. • Help in the establishment of vegetation for permanent control of erosion. • Dam is built in half-moon shape with the open end up-stream. • To construct a woven-wire dam, a row of posts is set along the curve of the proposed dam at about 1.2 m intervals and 60-90 cm deep.
  • 44. • Heavy gauge woven wire is placed against the post with the lower part set in a trench (15- 20 cm deep), and 25-30 cm projected above the ground surface along the spillway width. • Rock, brush or sod may be placed approximately up to a length of 1.2 m to form the apron. • For sealing the structure, straw, fine brush or similar material should be placed against the wire on the upstream side upto the height of spillway.
  • 45. Woven wire check dams (Source: Agr. Handbook No. 61. USDA, SCS
  • 47. Brush Dams  • Cheap and easy to build, but least stable of all types of check dams.  • Best suited for gullies with small drainage area.  • Centre of the dam is kept lower than the ends to allow water to flow over the dam rather than around it.  • For a distance of 3 to 4.5 m along the site of the structure, sides and bottom of the gully are covered with thin layer of straw or similar fine mulch.  • Brushes are then packed closely together over the mulch to about one half of the proposed height
  • 48. • Heavy galvanized wire is used to fasten the stakes in a row, as well as to firmly compress the brushes in places. • Sometimes large stones are also placed on top of brush to keep it compressed and in close contact with the bottom of the gully. • Major weakness is the difficulty of preventing the leaks and constant attention is required to plug openings of appropriate size with straw as they develop.
  • 49. Brush dam (Source: Agr. Handbook No. 61. USDA, SCS
  • 51. Loose Rock Dams • Loose rock dams made of relatively small rocks are placed across the gully. The main objectives for these dams are to control channel erosion along the gully bed, and to stop waterfall erosion by stabilizing gully heads. • Loose stone check dams are used to stabilize the small gullies. • The length of the gully channel is not more than 100 m and the gully catchment area is 2 ha or less. • These dams can be used in all regions. • Used in areas where stones or rocks of appreciable size and suitable quality are available.
  • 52. • Flat stones are the best choice for dam making. • Stones can be laid in such a way that the entire structure is keyed together. • A trench is made across the gully to a depth of about 30 cm. This forms the base of the dam on which the stones are laid in rows and are brought to the required height. • The centre of the dam is kept lower than the sides to form spillway. • To serve as an apron, several large flat rocks may be countersunk below the spillway, extending about 1 m down-stream from the base of the dam.
  • 53. Loose Rock Dams (Source: Agr. Handbook No. 61. USDA, SCS
  • 55. Log Check Dam • They are similar to plank or slab dams. Logs and posts used for the construction are placed across the gully. • They can also be built of planks, heavy boards, slabs, poles or old railroad ties. • The main objectives of log check dams are to hold fine and coarse material carried by flowing water in the gully, and to stabilize gully heads. • They are used to stabilize incipient, small and branch gullies generally not longer than 100 m and with catchment areas of less than 2 hectares. • The maximum height of the dam is 1.5 m from the ground level. Both, its downstream and upstream face inclination are 25 percent backwards.
  • 58. Boulder Check Dams • Boulder check dams placed across the gully are used mainly to control channel erosion and to stabilize gully heads. • In a gully system or multiple-gully system all the main gully channels of continuous gullies (each continuous gully has a catchment area of 20 ha or less and its length is about 900 m) can be stabilized by boulder check dams. • These dams can be used in all regions. • The maximum total height of the dam is 2 m. Foundation depth must be at least half of the effective height.
  • 59. • The thickness of the dam at spillway level is 0.7 to 1.0 m (average 0.85 m), and the inclination of its downstream face is 30 percent. • The upstream face of the dam is usually vertical. If the above-mentioned dimensions are used, it is not necessary to test the stability of the dam against overturning, collapsing and sliding. • The dimensions of the spillway should be computed according to the maximum discharge of the gully catchment area. • The form of the spillway is generally trapezoidal.
  • 62. Sandbag Check-Dam • Sandbag check-dams are made from used jute or polyethylene bags (50 kg) filled with soil/sand. • The bags are piled up to a maximum of 3 – 4 layers to form a small check- dam. • This cheap technique is particularly useful in areas with insufficient supply of stones for building ordinary check-dams. • By erecting sandbag dams large rills or small gullies (finger gullies) can be controlled, while they are not suitable for the treatment of large gullies.
  • 64. Gabion Check Dam • If the catchment area of a gully is 20 ha or less and the length of the gully is about 1 000 m, channel erosion will be controlled by boulder check dams, but the first check dam and its counter-dam should be constructed as gabions. • If the gully crosses a road, gabion check dams may be built above and below the road at the junction points. • In addition, gabion check dams combined with gabion retaining walls can be used to stabilize landslides in the upper portions of the gully. • Generally, it is neither necessary, nor economical to build a series of gabion check dams to control channel erosion along the gully beds.
  • 66. Permanent Gully Control Structures (PGCS) • If the erosion control programmer requires bigger structure, then PGCS are used. • PGCS, built of masonry, reinforced concrete or earth are efficient supplemental control measures in soil and water conservation. • They are helpful in situation where vegetative measures or temporary structures fail to serve the purpose of controlling the concentration of runoff or reclaim a gully. • PGCS are generally used in medium to large gullies with medium to large drainage area. • PGCS are designed to handle runoff from the heaviest rains that may be expected once in 25 to 50 years or more depending upon the estimated life of the structure.
  • 67.  Basic permanent structures, generally employed in stabilizing gullies are: ➢Drop spillway ➢Drop-inlet spillway ➢Chute spillway ➢Permanent earthen check dams
  • 68. Basic Components of PGCS  These components can be divided into three groups: 1. Inlet: Water enters the structures through the inlet, which may be in the form of a box or weir in a wall. 2. Conduit: The conduit receives the water from the inlet and conducts it through the structure. It restricts the water to a definite channel. The conduit may be closed in the form of a box channel or it may be open as in a rectangular channel. 3. Outlet: Its function is to discharge the water into the channel below at a safe velocity. The outlet
  • 69. Drop Spillway • It is a weir structure, in which flow passes through the weir opening, fall or drops on an approximately level apron or stilling basic and then passes into the downstream channel. • Its use is limited to a maximum drop of 3 m. • It is mainly used at the gully bed to create a control point. • Several such drop structures are constructed across the gully width throughout the length at fixed intervals. • The series of such structures, develop a continuous break to flow of water, causing deposition of sediments and thus filling the gully section. • Sometimes, the drop structures are also used at the gully head to pass the flow safely and controlling the
  • 72. Drop Inlet Spillway • A drop inlet or shaft spillway is one in which the water enters through a horizontally positioned circular or rectangular box type riser or inlet and flows to some type of outlet protection through a circular (horizontal or near horizontal) conduit. • The drop inlet spillway is ideally suited to conditions when there is need to control the downstream channel flow by providing a temporary storage upstream of the structure. • It consists of an earthen dam and a pipe spillway. • The dam provides the temporary storage of runoff from the contributing watershed while the spillway permits the design discharge to pass downstream.
  • 75. Chute Spillway • Chute (open channel or trough) spillway is a spillway whose discharge is conveyed from the upper reach of the channel or a reservoir to the downstream channel level through an open channel placed along a dam, abutment (supporting wall), or through a saddle. • Chute structures are useful for gully head control and they could be used for drops upto 5 to 6 m. • Chute spillways are constructed at the gully head to convey the discharge from upstream area of gully into the gully through a concrete or masonry open channel, when drop height exceeds the economic limit of drop structures. • Chute spillway has more advantage than a drop spillway, when a large runoff volume is required to be discharged from the area.
  • 78. Earthen Dam • An earthen embankment is a raised confining structure made from compacted soil. • The purpose of an earthen embankment is to confine and divert the storm water runoff. • It can also be used for increasing infiltration, detention and retention facilities. • Earthen embankments are generally trapezoidal in shape and most simple and economic in nature. • They are mainly built with clay, sand and gravel, hence they are also known as earth fill dams or earthen dams. • They are constructed where the foundation or the underlying material or rocks are weak to support the masonry dam or where the suitable competent rocks are at greater depth. • They are relatively smaller in height and broader at the base.
  • 79. Earthen Dam (Source: Michael and Ojha, 2012)
  • 81. Table 1. Yield of Cotton and Millet in farm fields treated with and without Contour bunding Technique Crop species Cotton (kg ha-1) Millet grain (kg ha-1) Contour bunding 1998 1322 No contour bunding 1617 * 890 ** * (p<0.05), ** (p<0.01) (Traore et al., 2017) (Southern Mali)
  • 82. Figure 1. Millet field in southern Mali without application of contour bunding (NCB) and with CB NCB CB (Traore et al., 2017) (Southern Mali)
  • 83. Table 2. Grain yield of crops in fields with and without Contour Bunding. Crop Yield (kg ha−1) and WP (kg mm−1) Bougouni district Koutiala district NCB WP CB WP NCB WP CB WP Sorghum 1292 2.11 1530* 2.50 1450 2.68 2120* 3.92 Maize 1360 2.22 2310** 3.78 1300 2.40 2020** 3.73 Millet 1370 2.24 2130** 3.48 1350 2.49 2720** 5.02 Groundn ut 1180 1.93 1400* 2.29 1114 2.06 1920** 3.54 (WP refers to water productivity; CB refers to contour bunding; NCB refers to no contour bunding.) *Statistically significant at P < 0.05, **Statistically significant at P < 0.01. (Birhanu, et al. 2019) (Southern Mali)
  • 84. Table 3. Runoff coefficient and soil loss in Bougouni and Koutiala districts during 2016 and 2017 cropping season Runoff coefficient (%) Soil loss kg ha−1 yr−1 Technique CB 19.25 b 4970 b No CB 35.62 a 13090 a P value 0.004 0.02 Site Koutiala 23.75 b 5733 b Bougouni 31.12 a 11,332 a P value 0.03 0.04 Year 2016 30.87 a 11,228 a 2017 24 b 5837 b P value 0.05 0.04 (Note: values with different letters are statistically different at P = 0.05. Column means represent runoff coefficient and soil loss; row values show technology, experimental site andyear of data record.) (Birhanu, et al. 2019) (Southern Mali)
  • 85. Table 4. Nutrient losses in eroded soil (kg ha−1 yr−1) under CB and non CB in Bougouni and Koutiala districts during 2016 and 2017 cropping season. Descriptio n C N P Ca Mg K Technique CB 45b 5b 4b 5b 3b 4b No CB 106a 11a 8a 9a 5a 7a P value 0.04 0.006 0.02 0.01 0.01 0.02 Site Koutiala 75 7 4 8 4 5 Bougouni 76 8 6 7 4 6 P value 0.97 0.98 0.06 0.6 0.62 0.76 Year 2016 112a 10a 7a 10a 5a 7a 2017 39b 5b 4b 5b 3b 3b P value 0.02 0.01 0.12 0.008 0.003 0.01 (Birhanu, et al. 2019) (Southern Mali) (Note: values with different letters are statistically different at P = 0.05.)
  • 86. Table 5. Month wise LAI and canopy interception for custard apple and atemoya during 2013-14. Plantatio n Month Leaf Area Index, LAI Canopy Interception, (mm) CCT Treated catchment Non Treated catchment CCT Treated catchment Non Treated catchment Custar d apple June 0.26 0.22 0.01 0.01 July 0.27 0.23 0.01 0.01 August 0.55 0.49 0.03 0.02 Septemb er 0.69 0.63 0.03 0.03 October 0.70 0.62 0.04 0.03 Novembe r 0.66 0.57 0.03 0.03
  • 87. Plantatio n Month Leaf Area Index, LAI Canopy Interception, (mm) CCT Treated catchment Non Treated catchment CCT Treated catchment Non Treated catchment Atemoya June 0.42 0.37 0.02 0.02 July 0.57 0.47 0.03 0.02 August 1.40 1.21 0.07 0.06 Septemb er 1.91 1.61 0.10 0.08 October 1.86 1.33 0.09 0.07 Novembe r 1.81 1.35 0.09 0.07 Decembe r 1.28 1.09 0.06 0.05 (Patode et al., 2015) (AICRPDA, Dr.PDKV,
  • 88. Table 6: Crop growth and yield components of sunflower as influenced by rainwater conservation and integrated nutrient management practices at Research farm during 2008–09. Treatments Plant height (m) Head weight (g plant−1) Stover yield (kg ha−1) Grain yield (kg ha−1) Rainwater conservation practices Flat bed 130.7 36.28 1120 886 Compartmental Bunding 144.7 48.47 1299 1079 Ridges and Furrows 140.8 47.37 1298 1072 S.Em.± 1.8 1.77 110 30 LSD (p < 0.05) 5.6 5.58 ns 119 Integrated nutrient management INM1 135.8 42.01 1128 954 INM2 138.3 44.07 1208 1011 INM3 142.1 46.05 1379 1071 S.Em.± 1.3 1.04 76 44 LSD (p < 0.05) 3.7 3.00 234 136 (Patil et al., 2015) (Research farm, Bellary)
  • 89. Table 7. Sediment losses on runoff plots as influenced by soil conservation measures Conservation Measure Soil loss (t/ha) September - May November - May Control, none 3.81a* 3.51a Control, fertilizer 1.59b 1.33b Bench terraces 1.13bc 0.68bc Grass bunds 0.81bc 0.40c Grass + Gliricidia bunds & mulch 0.53c 0.34c *Values followed by different letters are significantly different (p < 0.05) using protected LSD analysis (Stephen and Jill, (Kerinci,
  • 90.  Maharashtra has a rugged topography and basaltic geological formation so there is limitation on canal as well as well irrigation. There are many measures for the conservation of water and soil. They are performed by various government agencies. See the following table (Table 8)….. Objective Types of Measures Agency Water conservation Vanrai, Kaccha earthen, Bund, Nala Bandhara, Nala Plugs, check dam, Percolation tank Soil Conservation Department Soil Conservation Forestation, Continuous contour trench Forest Department & Social Forestry Contour trench, Contour bonding, Farm pond, Check dam Soil Conservation Department Strengthening of drinking water sources Fracture Seal Cementation, Jacket well, Stream blasting, Bore Blast Technique, Bore well flooding. Groundwater Surveys & Development Agency (Nitin Bajirao, 2016) (Maharashtra)
  • 91. Table.9 Yield and Growth parameters of Mango using Micro-catchments Treatments No. inflorescenc e /branch No of fruit set/ inflorescenc e Fruit yield (Kg/tree) T1-Half-moon 4.6 5.1 55.5 T2-Circle 3.9 4.0 50.3 T3-V-bund 4.4 4.6 53.0 T4-control 10.4 2.2 45.4 Cd 0.71 0.75 3.4 SEM 0.24 0.26 1.2 (Ali, 2017) (Ramanagara, Karnataka)
  • 92. Conclusion  The purpose of mechanical soil conservation measures is to protect the soil from the impacts of heavy rain and wind and prevent soil erosion.  Mechanical measures usually involve construction of mechanical barriers across the direction of flow of rain water to retard or retain runoff and thereby reduce soil and water loss.  Different measures can be adopted based on the different conditions and have a very significant effect on the soil loss and yields.