Types of Inter-Cropping are:
a. Mixed intercropping: Growing two or more crops simultaneously with no distinct row arrangement.
b. Row intercropping: Growing two or more crops simultaneously where one or more crops are planted in rows.
c. Strip Inter-cropping: Growing two or more crops simultaneously in different strips wide enough to permit independent cultivation but narrow enough for the crops to interact ergonomically.
d. Relay inter-cropping: Growing two or more crops simultaneously during part of the life cycle of each. A second crop is planted after the first crop has reached its reproductive stage but before it is ready for harvest.
Inter-cropping may be divided into the following four groups (Singh 1990).
i) Parallel Cropping: Under this cropping two crops are selected which have different growth habits and have a zero competition between each other and both of them express their full yield potential. E.g. 1) Green gram or black gram with maize.
2) Green gram or soybean with cotton.
ii) Companion Cropping: In companion cropping the yield of one crop is not affected by other, In other words, the yield of both the crops is equal to their pure crops. That the standard plant population of both crops is maintained. E.g.1) Mustard, wheat, potato, etc. with sugarcane 2) Wheat, radish, cabbage, sugar beat etc., with potato.
iii) Multistoried Cropping: or Multi-tire cropping: Growing plants of different height in the same field at the same time is termed as multistoried cropping. It is mostly practiced in orchards and plantation crops for maximum use of solar energy even under high planting density. e.g.
1) Eucalyptus +Papaya + Berseem
2) Sometimes it is practiced under field crops such as Sugarcane + Potato + Onion.
3) Sugarcane + Mustard + Potato.
4) Coconut + Pineapple + Turmeric/Ginger.
Multi-tire Cropping: Inter-cropping is mostly prevalent in plantation crops like coconut and areca nut. The practice different crops of varying heights, rooting pattern and duration are called multi-tire cropping. The objective of this system of cropping is to utilize the vertical space more effectively. In this system, the tallest components have foliage tolerant of strong light and high evaporative demand and the shorter component(s) with foliage requiring shade and or relatively high humidity. E.g. Coconut + black pepper + cocoa + pineapple.
The multi-tire cropping plan is shown in Fig. below. In this system, coconut is planted with a spacing of 7.5m Rooted cutting of black pepper are planted on either side of coconut about 75 cm away from the base. On the coconut trunk at a height of about one meter from the ground level, the vines of pepper are trailed. A single row of cacao is planted at the center of space between coconut rows. Pineapple is planted in the inter-space. Coconut growing to a height of more then 10 m. Cacao with its pruned canopy of about 2.5 m height and pineapple growing o about 1 m. height form the first and ground floors, respectively.