Agriculture Reference
In-Depth Information
6.3
IMPACT OF CLIMATE CHANGE ON CASHEW
Climatic variability like increase in temperature and moisture stress con-
ditions during flowering, fruit setting and nut development cause heavy
yield losses and adversely affect the nut quality even under better manage-
ment conditions. Any change in weather has direct effect on reproductive
phase of cashew. Cashew requires relatively dry atmosphere and mild win-
ter (15 to 20 °C minimum temperature) coupled with moderate dew during
night for profuse flowering. High temperature (>34.4 °C) and low RH
(<20%) during afternoon cause drying of flowers and thereby reduction in
yield. Unseasonal prolonged rainfall coupled with high wind velocity dur-
ing flushing and flowering resulted in significant nut yield losses as large
proportion of lateral branches remained as nonflowering laterals (Yaduku-
mar et al., 2010). Unseasonal rainfall and heavy dew during flowering and
fruiting also intensify the incidence of pests and diseases. In order to visu-
alize the climate change scenario at DCR farm, temperature and humidity
trends in last six years is furnished in Tables 6.3a and
6.3b.
TABLE 6.3A
Temperature and Relative Humidity Trends in Last Six Years at DCR
Month
2006-2007
2007-2008
2008-2009
Temp (°C)
RH (%)
Temp (°C)
RH (%)
Temp (°C)
RH (%)
Max
Min
FN
AN
Max
Min
FN
AN
Max
Min
FN
AN
September
25.4
17.8
75
53
30.5
-
94
75
32.1
-
94
72
October
33.0
21.8
93
59
32.0
-
93
67
34.7
-
93
57
November
33.3
17.3
90
43
33.8
-
91
60
35.4
-
90
56
December
34.5
17.1
95
51
33.9
-
86
45
34.8
-
91
56
January
34.9
18.4
93
45
34.3
-
94
58
35.4
-
92
52
February
36.2
22.3
92
45
34.8
-
91
52
37.3
-
92
46
March
36.8
29.4
88
46
34.5
-
93
52
38.0
-
90
44
April
36.8
-
90
49
35.1
-
91
54
37.8
23.8
89
49
May
34.5
-
90
59
35.0
-
92
58
36.6
23.6
93
55
June
29.3
-
96
79
29.6
-
96
87
32.8
23.1
96
79
July
28.7
-
96
86
31.1
-
94
78
29.9
22.5
96
80
August
29.8
-
94
79
31.0
-
94
73
31.3
22.9
97
80
