Plantation Crops

Soil and Climatic Requirements

Soil
Cashew being a hardy crop, it can be grown on a wide range of soils.
Avoid soils which are Heavy, Water logged and Excessive alkaline and saline soils (Z˼ÀÄ) as tap root will bend when reaching heavy soil.

Roots of cashew
Cashew has
1) Tap root --- Penetrates deep into soil,
2) Extensive network of lateral root system: Because of deep tap root and network of both primary and secondary roots plant gets adequate nutrition and water even during the period of prolonged drought.
Rhizosphere of cashew :
Depth : 60 cm contains over 70 per cent of active roots
Surface spread : upto 2 m radius from the base.

Climate for cashew
It is a sun loving tree and does not tolerate excessive shade. It cannot tolerate temperature above 450C during fruit set and development stage. Cashew is a tropical crop, loving warm and humid /moist climate of tropics.
1. Vicinity to the sea:

   • Mainly because minimum temperature is high. Cashew is a coastal tree (Particularly low land mainly because of low temperature range i.e., night temperature range of 13 to 18 º C) and closeness of sea is a favourable factor for cashew though it comes up in other areas i.e., even at about 1000 km away from the sea coast in India, Tanzania, Brazil etc.
2. Latitude:

   • Hopkin’s Bioclimatic law: Geographical co-ordinates (Latitude, Longitude and altitudes) influence flowering. For perennial trees flowering is influenced by these geographical co ordinates i.e., for every
     a) Every 400 feet altitude
     b) Every 1º Latitude and
     c) Every 5 º Longitude (From West to East) there will be delay in flowering by four days.
     Cashew comes up well between latitude of 25 º N and 24º S.
3. Altitude:

   • lower is the altitude better will be the performance: Many of the commercial plantations are up to an elevation of 600 -700 m. and lower is the altitude better will be the performance. There will be about three days delay in flowering for every 100 m altitude. At higher altitudes flowering and fruit setting is delayed i.e., delayed harvest than the coast. However, plantations are seen upto an elevations of 1000 m. asl.
4. Temperature:

   • Minimum Temperature is most important:
     A) Minimum temperature should not come down below 10ºC during flowering period.
     B) Maximum temperature of more than 35 ºC during reproductive / flowering period cause nut drop in cashew (East coast). In cashew though cashew can adopt a wide range of temperature from 15 º C to 45 º.
     C) Best range of temperature in 19 ºC to 35 º C. Cashew is very sensitive to low temperature i.e., frost injury.
   • The meteorological factors like night temperature (<10?C) and day maximum temperature (>35?C) during the reproductive phase of cashew may not be conducive for better flowering and nut weight across the east coast.
5. Sunshine/ Phototropism:

   • Cashew is a sun loving crop like coconut. It requires about 2000-2400 hr sunshine per year (i.e., > 6 hours per day). It requires about 1285 hr. sunshine in the flowering /fruit set period (Nov-March). In India sunshine recorded above 9 hours per day from Dec – May on the west coast during Flowering /Flushing and fruiting season.
   • Pest incidence vs sunshine: The major threat to cashew production across the west coast is the incidence of tea mosquito bug complex. It is, again, triggered by favourable weather. Cloudy weather during flowering enhances tea mosquito infestation.