Agriculture Reference
In-Depth Information
justifies the point that prevailing temperature of high elevations may have
a role in higher productivity, as rainfall by itself does not seem to have
much role as it is less compared to plains. Also, T
Tmin
of high elevations
had positive and both T
max
and T
Tmin
in plains had negative correlation with
pepper productivity indicating that climate change in terms of increase
in temperature may negatively influence black pepper productivity espe-
cially in plains whereas increase in T
Tmin
may have positive influence in
high elevations.
TABLE 11.3
Mean Temperature, Rainfall and Yield for Two Decades (1985-2004) in a
Few Black Pepper Growing Regions
Place
Temperature (°C)
Rainfall
(mm)
Mean yield
(kg/ha)
Mean Tmax
Mean Tmin
Difference
Wynad
27.3
17.6
9.7
1931
402
Idukki
27.5
15.6
11.9
1902
327
Cannanore
33.1
22.6
10.5
3348
241
Trichur
32.1
23.4
8.7
2752
239
Analysis of data of a decade on the extent of relationship between cli-
matic variables and productivity in six black pepper plantations in Coorg
indicated that one degree increase in maximum temperature can result in
up to 20.9 units (kgs) reduction in yield and one degree increase in mini-
mum temperature can result in up to 20.1 units increase in yield in differ-
ent plantations. One mm of rainfall can result in up to 0.05 units increase
in yield in different plantations. Tmin and rainfall showed positive influ-
ence on yield in 5 and rainy days showed positive influence in 4 out of 6
plantations (Krishnamurthy et al., 2011).
11.2.4 ELEVATED TEMPERATURE AND GROWTH OF BLACK
PEPPER
Plant height, leaf area and Photosynthetic rate of black pepper varieties
grown under elevated temperatures (2.7 degrees higher than ambient) was
less compared to those grown under ambient temperature during the initial
growth period. There was significant difference among varieties for leaf
area and diurnal variation in photosynthesis. Varieties such as Panniyur 5
