Agriculture Reference
In-Depth Information
Jones and Cree (1965) reported that high temperature during the June
drop period (May to June) can be very detrimental to the crop size of
navels. Later, Jackson and Hamer (1980) showed that three climatic fac-
tors accounted for 64% variation in yield of Cox orange between seasons.
Moss and Muirhead (1971) indicated a negative effect of high September
temperature on yield of Navel Orange in Australia, but had a positive ef-
fect of high temperature during November. Models have been developed
through long-term field experiments in Western Georgia to separate ef-
fect of fertilizer from climate and other incidental factors (Tsanava et al.,
1989). At low altitude in subtropical California, Valencia matures in about
9.5 months of anthesis in the hottest and about 14 months in the cool-
est climate zone (Monselise, 1981). Quantification analysis regarding the
contribution of environments, soil and management factors on yield of
Satsuma mandarin revealed that yield is more affected by physiographic
environment than either climate or even fertilizer application (Egashira et
al., 1990).
Tubelis and Salibe (1988) observed that production is correlated with
the orchard age and total rainfall received in 16 months, before picking
season the relationship (HA/CA = −18.91 + 20.35I + 0.8190P8 - 1.3788P9
+ 0.5805P10 - 0.149615, where HA/CA stand for production express in
kg plant -1 ; I, orchard's age expressed in years; P8, P9, P10, and P15, to-
tal rainfall received, respectively during the month of August, September,
October, and March of the year before picking) showed the best determi-
nation coefficient up to 98% up to year to year variation in yield, having a
good yield forecast ability, with substantial advance at blooming. Haggag
and Maksoud (1996) later developed a mathematical model for yield fore-
casting in navel orange in Egypt. Similar to above models, various other
mathematical models were developed for predicting temperature require-
ment for Texas citrus (Chance and Rathewell, 1979) and California Citrus
(Pehrson, 1966).
11.3
CLIMATE CHANGE AND CITRUS
Recent concerns about the “greenhouse effect” and damage to the ozone
layer have resulted in more concerted studies on the quantities, kinds, dis-
tributions, and behavior of climate in the different systems (Johnson and
Kerns, 1991). India is one of the 27 countries which are more likely to be
 
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