ISPRS Archives XXXVIII-8/W3 Workshop Proceedings: Impact of Climate Change on Agriculture
LONG RANGE REGIONAL CLIMATE FLUCTUATIONS/CHANGES AND THEIR IMPACT
ON AGRICULTURE—A CASE STUDY FOR CHHATTISGARH STATE IN CENTRAL INDIA
A.S.R.A.S. Sastri
Indira Gandhi Agricultural University, Raipur (CG) 492 006, asastri@yahoo.com
KEYWORDS: Climate Change, Agriculture, Rainfed Rice, Rainfall, Iimpact, Chhattisgarh, Central India
ABSTRACT:
Climate change is now felt as a reality world wide and intensive research work is being carried out on the scale of the change and its impact
on different sectors. However, the global changes are the totality of the regional scale changes which integrate to form a global scenario.
More over, the regional scale changes are much more than the global changes in either positive or negative intensities. So also their impact
at regional scale varies depending upon several factors including socio-economic conditions. In view of the above, studies were carried out
to assess the regional climate changes in Chhattisgarh state in Central India and their impacts on agriculture have been assessed. It was
found that the scale of variability is not the same in the entire state. In pockets, the rainfall decreased by 30-35 per cent while in some other
pockets, the rainfall decreased from 0-5 per cent only. With the changes in rainfall the general climate of the region has also changed. In
some pockets, the climate changed from ‘moist sub-humid’ type to ‘semi-arid’ and in other pockets it changed from ‘ moist sub-humid’ to
dry-sub-humid’. Such changes in the rainfall and there by the climate change have influenced the agriculture in the state. Studies revealed
that the farmers are adopting the climate change by shifting from long duration local rice varieties to short duration high yielding varieties
(HVY) of rice. It was also observed that during last 3 decades the wheat-growing zone has moved northwards.
changes. (Rao et al 2008) and the impact on agriculture is very
location specific which includes soil type, crop, and even the
socio-economic conditions of the farmers. In view of this it is
important to assess the impact of regional climate changes on
agriculture. An analysis of the regional climate changes in
Chhattisgarh state in central India. Fig 1 shows the Chhattisgarh
state.
1. INTRODUCTION
Climate change has now become a reality and several researchers
are working on this burning issue by working out the future
projections as well as assessing the impact in several sectors
including agriculture. While some researchers especially IPCC are
working on global climate change and its implications, researchers
in different countries are working on the regional scale climate
Figure 1. Agroclimatic Zones of Chhattisgarh State in India
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Chhattisgarh state is primarily an agrarian state with rice as a main
crop cultivated in about 3.6 million hectares during wet season.
Only about 20-22 per cent area is under irrigation and the rest of
the area is under rainfed conditions. As such any decline in rainfall
adversely affects the rice productivity and thereby the state’s
economy. Thus assessment of the regional climate changes at
micro-regional level and their impact on agriculture is necessary
for developing strategies for its mitigation. In view this, an
analysis has been made to find out the changes, if any, in the
rainfall pattern of the state in order to assess the impact and work
out mitigation techniques for the same. For this purpose about 58
stations in the state with availability of historical rainfall data in
different districts of the state have been considered. The rainfall has
been analysed month-wise as well as annual basis too. The rice is
cultivated in the state under a typical system of cultivation locally
known as ‘ direct seeded biasi’( Fig 2). Under this system the rice
seeds are broadcast in a pre-ploughed rice fields after the arrival of
monsoon rains. After 30-35 days after sowing and when sufficient
water is impounded in those bunded rice fields, the fields are
ploughed in the standing rice crop. This operation is called ‘biasi’.
This biasi operation is performed for two main reasons. The
number one is for weed control and secondly for creating semipuddled condition for minimizing the percolation losses.
Figure 2. Biasi Type of rice Cultivation Prevalent in
Chhattisgarh
Any delay in rainfall during the period of biasi (usually 20 July to
5 August), the biasi operation is delayed and hence the productivity
declines due to heavy weed-rice competition.
2. RAINFALL CHANGES
When the national scenario of rainfall changes in India were
analysed by Rupa Kumar et al (2002), it was found that the rainfall
in Central India is in decreasing trend while the same is in
increasing trend in Western and South-west India (Fig 3). As per
this macro-regional (national) analysis, attempts were made to
analyse the rainfall trend in Chhattisgarh region of Central India.
N
Figure 3. Annual Rainfall Trends Over India ( Rupa Kumar 2002)
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ISPRS Archives XXXVIII-8/W3 Workshop Proceedings: Impact of Climate Change on Agriculture
It was observed that in some stations the rainfall is decreasing in a
very alarming way and thus, the rice crop is often failing in those
areas. For example the annual rainfall of Mahasamund had
decreased from 1800 mm in the beginning of the century to about
800-900 by the end of 20th century. (Also at Kanker the annual
rainfall decreased from 1600 mm to about 900 mm during the last
century (Fig 3a and 3b)
the desertification process in the district (Sastri and Urkurkar
1996).
Climatic fluctuations in Mahasamund durig 1906-2000
80
Trend line
Moisture index (%)
Average rainfall annual rainfall 1371 mm
20
Moist sub-humid
0
Dry sub -humid
-20
2000
-40
1800
-60
Semi arid
1999
1996
1993
1990
1987
1984
1981
1966
1963
1960
1957
1954
1951
1948
1945
1942
1939
1936
1927
1924
1921
1918
1915
1912
1909
1933
Arid
-80
1400
1930
1600
1906
Years
1200
Figure 4a. Climate Change Scenario at Mahasamund
1000
Clim atic fluctuations in K anker during 1927-2000
800
80
Trend line
y = -0.5152x + 2.1103
R 2 = 0.2329
60
y = -8.4896x + 1522.4
R2 = 0.2539
0
1957
1967
1977
1990
2000
Years
Pattern
During
Last
Century
at
M oist sub-hum id
0
D ry sub hum id
-20
-40
Sem i arid
-60
Pattern of annual rainfall and its 5 year moving average
and trend line at Kanker from 1927-2000
Arid
2000
1997
1994
1991
1987
1981
1978
1975
1972
1969
1966
1963
1960
1957
1954
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
1951
1927
-80
1948
Figure 3a. Rainfall
Mahasamund
20
1945
1947
1942
1937
1933
1927
H um id
Trend line
40
Moisture index (%)
200
1930
400
1939
600
1936
R a in fa ll(m m )
2200
Years
Figure 4b. Climate Change Scenario During Last Century at
Kanker
When the long term rainfall records of about 58 stations of
Chhattisgarh state were analysed it was found that the rainfall is
changing in the state from 35 per cent in some localities to as low
as 5 per cent in some other localities (Fig 5).
y = -8.4896x + 1522.4
2
R = 0.2539
1927
1930
1933
1936
1939
1942
1945
1948
1951
1954
1957
1960
1963
1966
1969
1972
1975
1978
1981
1987
1990
1993
1996
1999
Rainfall (mm)
Humid
40
2600
2400
y = -0.6396x - 1.5383
R2 = 0.3733
60
Years
Series1
5 years moving average
Trend line
Figure 3b. Rainfall Pattern During Last Century at Kanker
3. CLIMATE CHANGES
As a result of the decreasing rainfall the climate of Mahasamund
had changed from moist sub-humid type to semi-arid type and if
the same trend continues the climate of Mahasamund may change
even to arid type of climate (Figure 4a). In the other words the
desertification process has just started in Mahasamund district of
Chhattisgarh state. Also, the soils of this district are sandy and
sandy loam as it is called the Trans-Mahanadi area and Mahanadi
the biggest river of Central India. The other characteristics of
deserts are raising dust, rainfall concentrated in a couple of months
and rest of the year, it is dry. All these characters of desert confirm
Figure 5. Spatial Variation of Rainfall Pattern in Chhattisgarh
4. FARMERS’ ADAPTATION
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ISPRS Archives XXXVIII-8/W3 Workshop Proceedings: Impact of Climate Change on Agriculture
Even in November month the maximum temperature started
increasing and hence, the wheat sowings in November is affected
even though the farmers take early duration rice varieties
The farmers earlier used to grow long duration tall varieties of rice,
which flower in mid-October and mature by mid November. As a
consequence of decreasing rainfall trends, especially in the month
of October (Fig 6), the long duration varieties started failing and
farmers started taking early or medium duration rice varieties since
last few years (Table 1)
Year
Local Varieties
(Area: ‘000 ha)
Transplanted
2008
2002
166.8
176.2
Improved Varieties
(Area: ‘000 ha)
Direct
Seeded
1422.7
1779.4
Transpla
-nted
1361.9
584.2
Direct
Seeded
1672.8
1356.7
Table 1. Changes of Local Varieties to Improved Varieties in
Chhattisgarh During Last 6 Years.
Figure 7b. The Temperature Pattern in November at Raipur
Thus the area under local varieties started decreasing since last few
years.
6. CHANGES IN CROPPING PATTERN
Post-monsoon (October-November) rainfall at Raipur
Due to changes in rainfall during kharif season and temperature in
rabi (winter) season, there are changes in the crops and crop
rotations in the state For example, the rice area in the state in
continuously decreasing. Because of decreasing rainfall pattern ,
rice is failing in fragile ecosystems like upland areas and as a result
the rice area is decreasing as shown in figure 8.
200.0
Post-monsoon rainfall
Trend line
5 years moving average
180.0
160.0
Rainfall (mm)
140.0
120.0
100.0
y = -0.8219x + 77.646
R2 = 0.0316
3 9 0 0 .0
R ic e
80.0
Area ('0 00 h a )
T re n d lin e
y = -2 6 .4 3 6 x + 3 6 6 5
2
R = 0 .2 4 4 4
3 8 0 0 .0
60.0
40.0
Area ('000 ha)
3 7 0 0 .0
20.0
19
71
19
72
19
73
19
74
19
75
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
0.0
3 6 0 0 .0
3 5 0 0 .0
Years
Figure 6. Pattern of October Rainfall at Raipur
3 4 0 0 .0
5. TEMPERATURE CHANGES
3 3 0 0 .0
2 0 0 0 -0 1
2 0 0 1 -0 2
2 0 0 2 -0 3
2 0 0 3 -0 4
2 0 0 4 -0 5
2 0 0 5 -0 6
2 0 0 6 -0 7
Y e a rs
During winter months the temperatures started slightly increasing
in the state during last 2-3 decades( Fig 7a & 7b)
Figure 8. Decreasing Trend of Area of rice Crop During Last
Few Years
The decreased area of rice is being replaced with other pulses and
oilseed crops like soybean ( Fig 9)
150.0
Soybean
Area ('000 ha)
Trend line
y = 11.374x + 28.534
2
R = 0.8479
Area ('000 ha)
120.0
90.0
60.0
30.0
0.0
Figure 7a. Decreasing Pattern of December Temperature
at Raipur
2000-01
2001-02
2002-03
2003-04
2004-05
2005-06
2006-07
Years
Figure 9. Increasing Trend of Soybean Crop in Chhattisgarh
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ISPRS Archives XXXVIII-8/W3 Workshop Proceedings: Impact of Climate Change on Agriculture
Similarly during winter (rabi) season, the area of wheat is in
decreasing trend as evidenced by the decreasing growth rates of
wheat during 90s decade as compared earlier decades as shown in
figure 10
7. FUTURE STRATEGIES
In view of t6he changing climate scenario both from decreasing
rainfall in wet season and increasing temperatures during winter
season, there is a need to review the existing cropping pattern at
micro-regional level and work out strategies for improvement in
the agricultural economy of the state. Some of the strategies to be
considered are
Shift in wheat area during last three decades (1971-2000)
In Chhattisgarh
Growth Rate
(%)
1971-1980
1991-2000
1981-1990
Figure 10. Decreasing Growth Rates of Wheat in 90s Decade as
Compared to 70s and 80s Decade
Trend line
Changes in crop rotation
¾
Water conservation through rainwater harvesting and
recycling
¾
Breeding drought resistant varieties suitable to a given
location
¾
Managing the village tanks with proper maintenance of
catchment area as well the de-siltation of the tanks.
Rao G.G.S.N, Rao, A.V.M.S. M., Vanaja, Rao, V.U.M. and
Ramakrishna, Y.S. 2008: Impact of regional climate changes
over India: In G.S.L.H.V. Prasad Rao, G.G.S.N. Rao, V.U.M.
Rao and Y.S. Ramakrishna (Eds) ‘Climate change and
agriculture over India’. AICRP on Agrometeorology, CRIDA,
Hyderabad pp: 13–48
y = 25.825x + 147.96
2
R = 0.6379
320.0
Area ('000 ha)
¾
REFERENCES
400.0
Area ('000 ha)
Change in cropping pattern
Thus, the regional climate changes are detrimental for crops and
crop production and necessary location-specific technologies need
to be developed.
The decreased area under wheat is mainly being replaced with
chickpea crop (Fig 11) which requires less water as well as
short and mild winters as compared to wheat
Gram
¾
240.0
Rupa Kumar, K, Krishna Kumar, K. and Pant, G.B. 2002.
Climate change- The Indian Scenario, In: Background paper
prepared by FICCI, International Conference on Science &
Technology, October 20 – 22, New Delhi 5-17
160.0
Sastri, A.S.R.A.S. and Urkurkar, J.S. 1996. Climatic variability
and crop productivity for Chhattisgarh region in Central India.
In: Abrol Y.P., Sulochana Gadgil and G.B. Pant (Eds) Climatic
variability and agriculture. Narosa Publishing House, New
Delhi pp 394–410
80.0
0.0
2000-01
2001-02
2002-03
2003-04
2004-05
2005-06
2006-07
Years
Figure 11. Increasing Area Under Chickpea During Last
Decade in Chhattisgarh State
160