2. DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY
INSTITUTE OF AGRICULTURAL SCIENCES
BANARAS HINDU UNIVERSITY
VARANASI-221005
DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY
INSTITUTE OF AGRICULTURAL SCIENCES
BANARAS HINDU UNIVERSITY
VARANASI-221005
Soil Degradation in India: Challenges and
Potential Solutions
Course seminar
3. 3
Soil Degradation : Extent and Distribution in India
Principle types and mechanism of soil degradation
Causes of soil degradation in India
A case study on Cost estimation of soil erosion
A case study on management of soil erosion in Rajasthan desert
Strategies to mitigate soil degradation
Research results documenting to soil conservation
Drivers of soil erosion
Conclusion
Introduction
4. 4
• Of India’s (TGA 328.7 Mha), 304.9 Mha comprise the reporting area with
264.5 Mha being used for agriculture, forestry, pasture and other biomass
production
• Soil degradation in India is estimated to be occurring on 147 million hectares
(Mha) of land (NBSS&LUP, 2004) out of which >94 Mha degraded by water
erosion
• India suffers from deleterious effect of soil erosion with an average soil
erosion rate was ~16.0 ton ha−1 year−1, resulting in an annual total soil loss of
5.33 billion tons throughout the country (Pandey et al., 2007)
• Nearly 29% of total eroded soil is permanently lost to the sea, while 61% is
simply transferred from one place to another and the remaining 10% is
deposited in reservoirs
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“The nation that destroys
its soil destroys itself.”
Franklin D. Roosevelt (1882 - 1945)
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"Soil degradation, decline in its capacity to support
functions and provide ecosystem services, is caused by
erosion, salinization, elemental imbalance
acidification, depletion of soil organic carbon,
reduction in soil biodiversity, and decline in soil
structure and tilth” (Lal, 2012).
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Soil degradation refers to the processes,
primarily human induced, by which soil
declines in quality and is thus made less fit for
a specific purpose, such as crop production
(FAO, 2011).
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“Soil is a part of Land, thus any
deterioration in it’s quality,
mass or volume either singly or
in combination, is also
deterioration of Land”
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“Soil degradation is closely linked to
poverty in the sense that, as the degree of
degradation increases, crop and animal
yields decline and people have both less to
eat and less to sell to support themselves.”
Clark & Wallace,2002
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Table 1: Extent of land degradation in India, as assessed by different organizations
Organizations
Assessment
Year
Degraded Area
(Mha)
National Commission on Agriculture, New Delhi 1976 148.1
Ministry of Agriculture-Soil and Water
Conservation Division, New Delhi
1978 175.0
Department of Environment, New Delhi 1980 95.0
National Wasteland Development Board, New
Delhi
1985 123.0
Society for Promotion of Wastelands
Development, New Delhi
1984 129.6
National Remote Sensing Agency, Balanagar,
Hyderabad
1985 53.3
Ministry of Agriculture, New Delhi (20th ed.) 1985 173.6
Ministry of Agriculture, New Delhi (25th ed.) 1994 107.4
NBSS&LUP 1994 187.7
NBSS&LUP (revised) 2004 146.8
National Remote Sensing Agency, Balanagar,
Hyderabad
2006 47.22
ICAR, New Delhi 2010 120.4
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15
0.2
7.6
2.6
5.3
1.9 1.9 1.2 2.2
4.6
1 0.2 0.6
4.2
7
15.3
0.1 1.5 1.3
6.3
2.8
0.2
8.1
11.4
26.2
13.1
6.1
54.5
43.9
39.8
67.1
41 42.6
89.2
53.9
28.2
53.8
60
33
59.9
75
31.6
52
55.4
33.2
25.4
36.1
31
24.8
41.5
33.2
59.1
42.4
39.3
0
10
20
30
40
50
60
70
80
90
100
Total Degraded Area % of Degraded Area to TGA
Fig. State-wise extent of degraded area in India (Mha),
Source: NBSS&LUP, 2005 on 1:250,000 scale
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Table 2. Estimates on the annual direct cost of land degradation in India
Parameters
NRSA
(1990)
ARPU
(1990)
Sehgal and
Abrol (1994)
Area affected by soil erosion (Mha) 31.5 58.0 166.1
Area affected by salinization,
alkalinization and waterlogging (Mha)
3.2 - 21.7
Total area affected by land degradation
(Mha)
34.7 58.0 187.7
Cost of soil erosion in lost nutrients
(Rs billion)
18.0 33.3 98.3
Cost of soil erosion in lost production
(Rs billion)
67.6 124.0 361.0
Cost of salinization, alkalinization and
waterloggingin lost production
(Rs billion)
7.6 - 87.6
Total direct cost of land degradation
(Rs billion)
75.2 - 448.6
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Area (Mha) affected by various erosion process in India
94
16
14
9
6 7
Water erosion
Acidification
Flooding
Wind Erosion
Salanity
Combination of Factors
Type of Erosion
NBSS&LUP, 2004 (Total 147 Mha)
ICAR, 2010 (Total 120.4 Mha)
94.9
0.9
3.7
17.9
2.7 0.3 Water and wind
erosion
Water logging
Soil alkalinity/sodicity
Soil acidity
Soil salinity
Mining and industrial
waste
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Classes Codes Area (in Mha)
Water Erosion
Loss of top soil
Terrain deformation
W
Wt 83.31
Wd 10.37
Wind Erosion
Loss of top soil
Loss of top-soil/terrain deformation
Terrain deformation/over blowing
E
Wt 4.35
Et/Ed 3.24
Ed/Eo 1.89
Chemical Degradation
Salinization
Loss of nutrients (En) – (Acid soils)
C
Cs 5.89
En 16.03
Physical Degradation
Waterlogging
P
Pw 14.29
Others
Ice caps/Rock outcrops/Arid mountain I/R/M 8.38
Total 147.75
Table 3: NBSS&LUP soil Degradation Classes, Derived From 1: 250,000 soil map (2004)
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“Perhaps the most dominant soil degradation
processes are soil erosion and organic
matter decline.”
B.A. Stewart, R. Lal, and S.A. El-Swaify. Sustaining the Resource
Base of an Expanding World Agriculture. In: Soil Management for
Sustainability. R. Lal and F.J. Pierce (eds.), 1991.
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SOIL DEGRADATION
NATURALHUMAN -INDUCED
URBAN LAND
• Pollution
• Compaction
• Erosion
INDUSTRIAL LAND
• Soil Compaction
• Soil Contamination
• Acid Rain
AGRICULTURAL
LAND
PHYSICAL
• Pan formation
• Hard-setting
CHEMICAL
• Leterization
• Calcification
• Leaching/
Illuviation
BIOLOGICAL
• Decline in
soil diversity
PHYSICAL
• Compaction
• Crusting
• Water imbalance
• Impeded erosion
• Runoff
CHEMICAL
• Acidification
• Nutrient depletion
• Leaching
• Nutrient imbalance
• Salanization/alkanization
BIOLOGICAL
• Decline in soil organic C
• Soil biodiversity reduced
• Decrease in biomass C
Principal types of soil degradation: (i) natural (ii)Human-induced
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2 Primary drivers of soil erosion
Water : non arid areas
Gravity involved in both wind and water erosion
(>94 mha area subject to wind and water erosion in India)
Drivers
Wind : arid and semi arid areas
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Table 4:Common soil stress and related degradative processes
Stress Principal degradative processes
Heavy load due to extensive
mechanization (vehicular traffic)
Physical degradation, eg., crusting,
compaction, structural decline and poor soil tilth
High intensity of rain and overland
flow, high wind velocity
Accelerated erosion by water and wind
High evaporation demand and high
salt concentration in the profile
Drought, aridization or desertification,
salinization or sodification
Poor internal drainage, and slow
surface drainage
Soil wetness and anaerobiasis
Intensive cropping
Chemical degradation, nutrient imbalance and
soil organic matter depletion
Intensive use of agrochemicals and
monoculture
Biological degradation, acidification and
reduction in soil biodiversity
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1. Overgrazing
2. Deforestation
3. Industrialization
4. Overpopulation (Land Shortage, Land Fragmentation and Poor Economy)
5. Over exploitation/Mining of land
6. Agricultural activities leading to soil degradation
i. Low and Imbalanced Fertilization
ii. Excessive Tillage and Use of Heavy Machinery
iii. Crop Residue Burning and Inadequate Organic Matter Inputs
iv. Poor Irrigation and Water Management
v. Poor Crop Rotations
vi. Pesticide Overuse and Soil Pollution
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Current position:
Cattle population: 467 Million
Area of pasture land: 11 Mha
Implying an average of 42 animals per
hectare
Threshold level: 5 animals per hectare
(Sahay, K.B. 2000)
Too many grazing cattle, sheep, or goats, which can destroy vegetation
and as a result, soil is exposed toerosion.
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Current position:
Per capita forest land in the country is
only 0.08 ha compared to a requirement of
0.47 ha to meet basic needs.
Average rate of soil loss due to wind
and water erosion in India is 16.4 tons per
hectare annually with an annual total loss of
5.334 billion tons [CSWCRTI Dehradun, 2010]
and in US it was 1.725 billion tons in 2007.
Deforestation is both, a type of degradation by itself, and a cause for
othertypes of degradation, principally, water erosion
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Underground tanks storage,
application of pesticides, oil and fuel
dumping, leaching of wastes from
landfills or direct discharge of
industrial wastes to the soil.
In industrialized urban regions, pollution can harm the soil of farms and
makethelandunstablefor farming
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Current position:
India has
• Land area is about 2.5% of global land
• Supports 16% of global human population
and ~20% of livestock population
• Average size of land holding declined
from 2.3 ha to 1.3 ha during 1970–2000
with per capita land of 0.32 hectare in
2001
The needs also increase and utilize forests resources. To meet the demands of
rapidly growing population, agricultural lands and settlements are created
permanently by clearing forests
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Negative effects of mining are water scarcity due to lowering of water table, soil
contamination, part or total loss of flora and fauna, air and water pollution and
acidmine drainage
Mineral Production (Mt)
Overburden/Waste
(Mt)
Estimated Land
Affected (ha)
Coal 407 1493 10,175
Limestone 170 178 1704
Bauxite 12 8 123
Iron ore 154 144 1544
Others 9 19 -
Table 5. Mineral Production, waste generation and land affected in 2005-06 (Data
source: Sahu and Das, 2011).
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Current position:
India has
• Imbalanced consumption ratio of
(N:P:K fertilizers)
• 6.2:4:1 in 1990–1991 has widened to
• 7:2.7:1 in 2000–2001 and
• 5:2:1 in 2009–2010 compared with
• Target ratio is 4:2:1
Agricultural activities and practices can cause land degradation in a number of
ways depending on land use, crops grown and management practicesadopted
i. Low and Imbalanced Fertilization
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In India, ~500 Mt of crop residues are generated every year and ~ 125 Mt are burned.
Crop residue generation is greatest in Uttar Pradesh (60 Mt) followed by Punjab (51 Mt)
andMaharashtra (46Mt)
Ministry of New andRenewable Energy (2009)
ii. Crop Residue Burning and Inadequate Organic Matter Inputs
Residue generation by different crops in
India (MNRE, 2009)
Burning of rice residues, a prevalent
practice in northwest India
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Excessive tillage coupled with use of heavy machinery for harvesting and lack of
adequate soil conservation measures causes a multitude of soil and environmental
problems
iii. Excessive Tillage and Use of Heavy Machinery
Less CO2 leaves soil when no-tilled
Compaction due to use of heavy
machinery and others
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Expansion of canal irrigation (like the Indira Gandhi Nahar Project, for instance) has been
associated with widespread waterlogging and salinity problems in areas, such as in
the Indo-Gangetic Plains.
iv. Poor Irrigation and Water Management
Waterlooging and salinity due to poor irrigation management
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Improper crop rotation coupled with lack of proper soil and water conservation
measures are important reasons contributing to soil erosion in lands under
cultivation
v. Poor Crop Rotations
Table 6: Effect of crop rotation on soil organic matter in soils
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Overuse of chemical fertilizers and pesticides have effects on the soil organisms
that are similar to human overuse of antibiotics. Indiscriminate use of chemicals
might work for a few years, but after awhile, there aren’t enough beneficial soil
organisms to hold onto the nutrients” (Savonen, 1997)
vi. Pesticide Overuse and Soil Pollution
Consumption pattern of pesticides (Aktar et al., 2009)
Once they has been sprayed, it
does not disappear
completely. Some of it mixes
with the water and seeps into
the ground. The rest of is
absorbed by the soil and plant
itself.
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The major outcomes of land degradations are as follows:
Decline in the productive capacity of the soil (temporary or permanent)
Decline in the soil “usefulness”.
Loss of biodiversity
Increased vulnerability of the environment or people to destruction or
crisis
Accelerated soil erosion by wind and water
Soil acidification and the formation of acid sulphate soil resulting in barren
soil
Soil alkalinisation owing to irrigation with water containing sodium
bicarbonate leading to poor soil structure and reduced crop yields
Soil salinization in irrigated land requiring soil salinity control to reclaim
the land
Soil water logging in irrigated land which calls for some form of
subsurface land drainage to remediate the negative effects.
Destruction of soil structure including loss of organic matter.
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A case study on Cost estimation of soil erosion and nutrient
loss from a watershed of the Chotanagpur Plateau, India
(Area- 14 square km, slope - 1% to 5%, annual rainfall –
1300–1500 mm, soil texture -Sandy clay loam)
Gulati and Rai, 2014
1. It was observed that overland flow was greatest in orchard (30.73%) and
lowest in vegetable field (15.84%).
2. Soil loss from the field plots ranged between 9 and 37 tonnes/ha during the
monsoon months.
3. Nutrient leaching was highest in paddy fields. A strong positive correlation
was observed between organic carbon and soil loss (P < 0.01).
4. On an average, 590 kg of macro-nutrients (N, P and K) were lost per hectare
during the monsoon season. Approximately INR 8,893 ha–1 (US$ 137 ha–1)
would be required to replace this loss through inorganic fertilizers.
5. Agricultural practices in mountain areas should be strengthened with more
agroforestry components to promote conservation of soil, water and
nutrients.
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Case study :Management of soil erosion in the Rajasthan
Desert
What is the Issue?= Desert and semi-desert conditions occur in Rajasthan
and there has been advance of the desert and encroachment of sand on fertile
lands due to desertification and soil erosion.
There has been a programme of action which includes:
1. Creation of a vegetation belt—five miles wide—along the western
border of Rajasthan.
2. Improvement of land-use practices, especially the creation of shelter
belts of trees by cultivators
3. A Desert Research Station is being set up at Jodhpur to investigate the
problems of desertification. Research on soils, land-use and afforestation
practices would be undertaken at this station.
Planning Commission, GOI
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• Soil Erosion
• Nutrient runoff loss
• Waterlogging
• Degradation
• Acidification
• Compaction
Negative
• Crusting
• Organic matter loss
• Salinization
• Nutrient depletion by
leaching
• Toxicant accumulation
• Conservation tillage
• Crop rotation
• Improved drainage
• Residue management
• Water conservation
• Terracing
Positive
• Contour farming
• Chemical fertilizer use
• Organic fertilizer use
• Organic fertilizer (Green manure)
• Improved nutrient cycling
• Improved system to match soil
climate and cultivars
Soil
Productivity
Soil Degradation Processes Soil Conservation Processes
The relationship between soil degradation processes and
soil conservation practices
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Soil Erosion Control
Water Harvesting (Watershed Approach), Terracing and Other
Engineering Structure
Landslide and Mine-spoil Rehabilitation and River Bank Erosion
Control
Intercropping and Contour Farming
Integrated Nutrient Management and Organic Manuring
Reclamation of Acid and Salt Affected Soils and Drainage
(Desalinization)
Water Management and Pollution Control
Vegetative Barriers and Using Natural Geotextiles, Mulching
and Diversified Cropping
Agro forestry
Conservation Agriculture (CA)
Disaster (Tsunami) Management
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Figure 1. Soil organic C (SOC) stabilization
in the 0 to 45 cm soil layer as affected by 32
years of continuous annual fertilization
under soybean-wheat cropping in a sandy
clay loam soil of the Indian Himalayas
Figure 2. Ratios of labile and recalcitrant
pools of total SOC and applied C stabilized in
soils by depth after 32 years of cropping
with different fertilization (error bars
indicate SEm
Source: Bhattacharyya et al. (2011)
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Table 7: Effects of balanced fertilization (NPK and NPK + FYM or compost) on C build up
in soils under different cropping systems
Build-up = [(NPK//NPK + FYM – Control)/Control] × 100; Build-up rate = [(NPK//NPK
+ FYM – Control)/year]; R-M-S, rice-mustard-sesame; R-W-F, rice-wheat-fallow; R-F-B,
rice-fallow-berseem; R-W-J, rice-wheat-jute; R-F-R, rice-fallow-rice, FYM, farmyard manure.
(Data source: Mandal et al. [2007]).
Cropping
System
C Build-Up (%) in Treatments over
the Control Plots
C Build-Up Rate (Mg C ha−1 year−1 )
over the Control Plots
NPK NPK + FYM NPK NPK+FYM
R-M-S 51.8 a 55.7 a 1.91 a 2.05 a
R-W-F 16.8 c 23.4 c 0.27 b 0.37 c
R-F-B 9.3 d 24.7 c 0.13 c 0.36 c
R-W-J 14.9 c 32.3 b 0.11 c 0.25 d
R-F-R 33.5 b 54.8 a 0.28 b 0.45 b
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Table 8: Runoff and soil loss under different crops on varying slopes at
research farm, Bellary (Karnataka)
(Source: CSWCR&TI Annual Report [2009])
Treatments
Runoff (mm) Soil Loss (ton ha−1 )
Sorghum Chickpea Sorghum Chickpea
0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0
Slope (%)
With
fertilizer
52.3 66.78 94.8 48.71 64.45 84.56 2.45 4.04 5.67 2.01 2.72 4.79
Without
fertilizer
63.16 66.85 101.79 49.06 65.64 92.99 2.72 4.79 6.08 2.19 3.31 5.35
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Year Rainfall (mm)
Runoff (mm) Soil Loss (ton ha-1 )
BBF FOG BBF FOG
2003 1058.0 163.0 (15.4%) 214.9 (20.3%) 2.0 2.9
2004 798.2 124.0 (15.5%) 183.3 (23.0%) 0.7 1.5
2005 946.0 177 (18.7%) 246 (26.1%) 1.4 3.1
2006 1513.0 502 (33.2%) 873 (57.7%) 3.5 6.4
Table 9: Seasonal rainfall, runoff and soil loss from different land configuration,
broad-bed and furrow (BBF) and flat on grade (FOG)
Note: Values within parentheses indicate the percent of total rainfall
[Data source: Mandal et al. (2013)]
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Table 10. Ameliorative effects of tree plantation on salt affected soils of India
Region Tree Species
Soil
Depth
(cm)
Original After
References
pH
EC
(dSm−1)
pH
EC
(dSm−1)
Karnataka
Acacia nilotica
(Babul)
(age 10 years)
0–15 9.2 3.73 7.9 2.05
Basavaraja
et al. [2010]
Karnal
Eucalyptus
tereticornis
(age 9 years)
0–10 10.06 1.90 8.02 0.63
Mishra
et al. [2003]
Lucknow
and
Bahraich in
north India
Terminalia
arjuna (Arjun)
0–15
9.60
±0.42
1.47±0.45
8.40±0.27 0.31±0.07
Singh and
Kaur [2012]
Prosopis
juliflora (Kikar)
8.70±0.33 0.42±0.06
Tectona grandis
(Teak)
6.15±0.23 0.06±0.006
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Fig. Impacts of conservation agriculture (CA) on soil aggregation in the 0–5 cm
layer in the upper IGP
(Source: Bhattacharyya et al. [2013])
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Appropriate mitigation strategies of the nearly 147 Mha of existing
degraded land in the sub-continent of India are of the utmost
importance
With changing climate, land degradation is expected to only increase due
to high intensity storms, extensive dry spells, and denudation of forest
cover.
Combating further land degradation and investing in soil conservation is a
major task involving promotion of sustainable development and nature
conservation
Sustainable agricultural intensification using innovative farming practices
have tremendous potential of increasing productivity and conserving natural
resources, particularly by sequestering SOC and improving soil quality.
Novel CA practices include: permanent broad bed with residue retention
under maize/cotton/pigeon pea-wheat cropping systems and seasonal
tillage alterations under rainfed and rice-based agro-ecosystems.
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For sure, the non-edible (to animals) agricultural residues must not be
burnt and should be used for mulching along with growing of cover crops,
preferably legumes.
Improved grazing practices, irrigation management, control on urban
sprawl and control and management on mining are a few other solutions
for preventing land degradation.
Domestic and municipal wastes, sludges, pesticides, industrial wastes, etc.
need to be used if possible to close nutrient cycles, but with caution to avoid
the possibility of soil pollution.
Future research should focus on enhancing nutrient and water use
efficiencies and reduction in the pesticide use under CA.
A well-defined integrated land use policy to include rural fuelwood
and fodder grazing is urgently needed at the implementation level
Cont......
The processes of soil degradation are the mechanisms responsible for the decline in soil quality (Fig. 2) and they are grouped into three types: physical, chemical and biological types, each of which has different processes
affecting it (Fig. 3). In Fig. 4 it is shown that soil degradation is governed by environmental agents and catalysts which propel their actions.
When it rains on hillslopes, the splash of the raindrops makes the small soil particles move around. Some water runs off on the hillsides, which causes erosion of soil in which plants grow.
The processes of soil degradation are the mechanisms responsible for the decline in soil quality (Fig. 2) and they are grouped into three types: physical, chemical and biological types, each of which has different processes
affecting it (Fig. 3). In Fig. 4 it is shown that soil degradation is governed by environmental agents and catalysts which propel their actions.