Citrus trees grow in almost any soil that is well-drained, sufficiently
aerated and allows tap root to penetrate to the desired depth.
Planting of citrus trees in unsuitable soils and sites has often led
to early decline and sometimes total failure of many orchards in Andhra
The decline of Batavian orange plantations in Palacol area, the reduction
in area under cultivation of Vadlapudi orange in parts of Guntur, Krishna
and Godavari districts and the extremely short life of Sathgudi plantations
in Anantapur district, revealed that presence of a hard pan formed due
to calcium carbonate concretions in the soil determines the depth of
the active root system and age at which citrus decline starts.
Early decline (even before 6-7 years after planting) was found in
soils where the hard pan occurred in the soil, within a depth of 30
In order to allow the tree to develop a sufficiently deep root system,
care should be taken to select deep, well-drained and medium-loamy soils
without any hard pan in the sub-soil within the root zone.
The hard pan restricts the root system and creates stagnant moisture
conditions within the root zone for prolonged periods, causing root
rot and early decline of trees.
In shallow soils, "die-back' of twigs and sparse foliage and low yields
are common symptoms in sweet orange.
Decline of trees is generally associated with soils containing excess
i.e. more than 10 % free lime.
Presence of lime does enhance growth of citrus plants for a few years
but the problems of die-back begins when feeding roots come into contact
with calcium carbonate pan.
Further, excess presence of free lime reduces the availability of
phosphorus, iron, manganese and zinc and increases deficiencies/disorders
associated with these elements.
Heavy soils with high clay content (more than 30%) will have inadequate
drainage and insufficient aeration. Poor aeration of the soil reduces
the absorption power of roots and may hasten the decline or trees.
Presence of a free water table within the reach of the root zone also
represents a hazard.
In general, the roots of citrus tree do not get injured so long as
the water table remains beneath 0.45m.
The main threat to the health of an orchard is a fluctuating water
A water table below 1.5 metres in all seasons is conducive for citrus.
Because of a comparatively shallow root system, acid lime performs
well in high water table areas like that of Tenali.
Soil reaction (pH) has a marked influence on the availability of plant
Citrus prefers soils with a pH range of 6 to 7.
However, by adopting suitable management practices, citrus crop is
being raised successfully in soils with a pH between 5.5 to 8.5.
Soils with a pH of more than 8.5 are unsuitable for successful growth
and productivity of citrus.
Citrus trees are extremely susceptible to salt injury to should never
be planted in saline soils.
Further, in alkaline, saline and acid soils, citrus trees suffer from
several nutritional disorders and root diseases, remain unthrifty and
exhibit early die-back symptoms.
Inadequate drainage and salinity aggravate leaf mottling disorders.
In light textured soil, the electrical conductivity of 1:2 soil water
suspension should not be more than 0.8 m mhos/cm during monsoon season.
Although citrus plants grow well in tropical and subtropical climates,
the commercial yields of citrus orchards in tropical regions are commonly
50% or less than that of those obtained in sub-tropical regions.
In tropical areas, citrus fruit tend to bloom sporadically whereas
in sub-tropical regions it tends to bloom profusely in the spring, after
winter dormancy, resulting in only one major crop in a year.
This is because in sub-tropical regions the shoots are dormant during
the winter and when spring comes and with it the change in temperature;
a major portion of the shoots flower at one time.
In tropical regions on the other hand, dormancy is not natural but
induced by creating moisture stress (with-holding water supply for 4-6
weeks) to synchronize the flowering of a major portion of the shoots.
This is a common practice followed in Peninsular India.
Production technology generated at various research centres in India
during the last five decades has helped a great deal in the rapid development
of commercial citri-culture in the country.
The agro-techniques developed for the sweet orage and acid lime at
the Fruit Reasearch Station, Ananthrajupet (Kodur) made it possible
to obtain exceptionally high yields in certain well managed citrus orchards
in the state.
Citrus species make little or no shoot elongation at temperatures
below 120C or above 450C.
For sweet orange and lime, temperatures between 280 - 320C
are considered ideal for optimum growth and productivity.
In the arid and semi-arid areas of Andhra Pradesh, while high moisture
stress often limits growth, more often than the temperature, high temperatures
at the time of flowering result in a low fruit set in sweet oranges.
Further, hot winds tend to cause excessive evopo-transpirational losses
and often result in fruit drop.
Citrus species do best in regions with an annual rainfall of 1250
to 1850 mm.
As much, in arid and semi-arid areas, an adequate irrigation water
supply is required for maintaining desirable soil moisture conditions.
In the humid tropics, citrus fruit tend to be large, with thin and
smooth rind, has high juice content as compared to those grown in arid
and semi-arid regions.
However, high humidity or rains, after a prolonged dry spell often
causes the fruit to spilt.
In the tropics, lack of cold temperature causes very low breakdown
of chlorophyll and synthesis of carotinoids in the rind, so the fruit
may be pale green or at best pale yellow at maturity.
Also, fruit tend to have lower total soluble solids and acid concertarions
in the juice in the arid tropics.
However, acid lime produced in the tropics develop a quite attractive
colour and is ideal for export.
The acid concentrations are equally high in tropical and sub-tropical