Intercropping in Cashew Orchards

2. • Growing one or more crops with a major crop is known as
intercropping.
• The perennial crops such as cashew, coconut, mango etc. have a
long gestation period compared to the annuals before coming to
the bearing stage.
• Therefore, income is not generated from young cashew plants
until bearing, which takes 3 to 5 years from planting.
• During this period, a considerable amount of money has to be
spent on cultural practices such as fertilizer application, weed
management, pest and disease control etc.
Introduction

3. • Therefore, the growers face the problem of incurring expenditure
without any income during this gestation period.
• When young cashew is planted, the land remains exposed to the
vagaries of weather until a canopy is formed to provide an
adequate ground cover.
• As a result, these fields are subjected to erosion, excessive evapo-
transpiration, and proliferation of weeds.
• In order to minimize such undesirable effects, it is necessary to
provide a ground cover by planting cover crops or using suitable
mulches.

4. • However mulching is restricted due to the unavailability of
recommended materials in adequate quantities and the high cost
involved (Wijeratne et al., 1994).
• Furthermore, growing cover crops and/or mulching will not provide
any direct financial gain to the farmers.
• As the inter row space of cashew is around 7-8 meters, this space
could be utilized to plant intercrops until it is fully covered by the
cashew canopy.
• Hence the farmers will be able to gain a considerable income by
intercropping cashew plantations during the unproductive, early
periods of 3 / 5 years after planting.

5. Potential of intercropping young cashew plantations
• Perennial crops such as coconut, rubber and cashew are
normally planted wide apart which permits optimum growth
and development of the canopy.
• During the immature period of these crops, considerable land
area is unutilized.
• Cashew is normally planted at a spacing of 7.6 X 7.6 m.
• Hence, the wider inter row space can be used for raising
intercrops until cashew canopy covers the inter row space.

6. • Rainfall, light and soils are the major factors influencing
successful intercropping systems with cashew.
• Cashew is grown predominantly as a rain fed crop in dry zone
areas of Sri Lanka.
• In the dry zone there are two rainy seasons from September to
January (Maha) and April to July (Yala).
• During the two rainy seasons these areas receive sufficient
rainfall, which reduces competition petition for soil moisture
between cashew and intercrops.

7. • Further these areas receive sample amounts of sunlight
throughout the year.
• In Sri Lanka over 80% of grain legumes are grown under rain fed
conditions in the dry zone and in some parts of intermediate zone
(Jayasekera et al., 1992).
• Therefore inter-row space of young cashew plantations could be
utilized to intercrop annual grain legumes and cereals.
• Abeysinghe (2001) reported that annuals such as grain legumes
and cereals can be successfully intercropped in young cashew
plantations.

8. Benefits of intercropping in cashew plantations
1) Extra income for farmers.
2) Smother weed growth.
3) Improve soil fertility.
4) Protect soils from erosion.
5) Conserve soil moisture.
6) Efficient utilization of resources to improve productivity of the land.
7) Create more employment opportunities.
8) Provide food for home consumption.

9. 1) Extra income for farmers
• The age at which a cashew tree starts flowering is influenced by
the growing conditions and probably by genetic factors.
• Cashew trees growing under favorable conditions may produce
their first crop at the age of 3 to 5 years (Mandal, 1997).
• Therefore, income is not generated from young cashew fields
during the first 3 to 5 years of the immature period.
• Cashew small holders are typically recognized as low-income
group who live in the dry zone with limited financial resources
and infrastructure.

10. • However various cultural practices such as land preparation,
fertilizer application, weed control and pest and disease control
need to be carried out during this immature period of cashew.
• Therefore, the growers are facing problems of bearing high
expenditure for cultural practices without any income during this
unproductive gestation period, even though subsidies are
available from the Sri Lanka Cashew Corporation.
• Hence, without an additional income during the immature stage
of cashew, the smallholders are little reluctant to cultivate
cashew in their lands.

11. • As there is no any income, often young cashew fields are
neglected and it leads to proliferation of weeds and casualties.
• During this period of immaturity, however, it has been possible to
utilize the inter-row space for growing selected annual crops that
would generate an income to the growers until cashew trees are
brought into bearing.
• However, results showed that crops cannot successfully be
intercropped with cashew beyond three years after the
establishment of cashew (Abeysinghe, 2001).

12. 2) Smother weed growth
• The main task after establishment of cashew plants is to control
excessive weed growth, which might otherwise severely deplete
soil moisture and compete for nutrients.
• Weed growth is seen to be maximum after monsoons and
harvesting becomes a problem if weeds are not removed.
• The production as well as productivity of cashew plantations in
Sri Lanka is quite low due to many factors including the problem
of weeds.

13. • Weed control is also the main problem especially in young cashew
plantations.
• The development of cashew seedlings in unweeded plantations is
very slow.
• Due to competition for light, water and nutrients, shoots of
cashew plant develop slowly and as a result, root development is
also slow.
• Depending upon the severity of weed infestation the yield
reduction of cashew is recorded to be between 60% and 70% (Abdul
Salam et al., 1993).

14. • Generally weed control is often the principal operation in tropical
cropping fields.
• Over 50% of total labour and 40% of production costs are spent on
weed control (Akobundu, 1980).
• Therefore the management of weed is needed in the cropping
fields.
• Sickle and slash weeding are the most common methods of weed
control adopted in cashew plantations.
• However, the cost and availability of labor are generally limited to
carry out these methods.

15. • Weed control can be achieved by mulching (Othieno, 1980) and alley
cropping practices (Jama et al., 1991, Rosecrance et al., 1992).
• However intercropping has the potential to control weeds.
• Plunekette et al., (1977) and Shetty and Rao (1980) have reported
that intercropping suppress weed growth.
• This is because of early canopy closure, which prevents light
penetration.
• The extent of this effect will depend on the leaf area index of the
component crops.

16. • It has been observed that well spread. dense canopy of pigeonpea
suppressed weed growth.
• Rao and Shetty (1976) reported that maize and cowpea were
more weed suppressive than groundnut.

17. 3) Improve soil fertility
• Soil fertility status can be improved by the incorporation of
intercrop residues with soil.
• The nutrient status of the soil is commonly improved by
intercropping (Onim et al., 1990), due to intercropped biomass, which is
incorporated into soil.
• Intercropping helps to improve soil fertility characteristics (Kendaragama
and Handawela, 1994).

18. • Improvement of soil organic matter and soil plant nutrient contents
could be seen by the incorporation of plant biomass with soil and it
substantially improves soil fertility. Gunaratne and Heenkende (1994)
• Better retention of soil fertility and lower soil temperatures in
intercropping systems lead to increased earthworm activity (Hulugalle and
Ezumah, 1991).
• Reduced soil temperature and improved moisture conditions due to
intercropping may favor multiplication and growth of some soil
microorganisms.
• Greater populations of active soil bacteria under maize/ legume
intercrops. Singh et al., (1986)

19. 4) Protect soils from erosion
• Intercrops cover the ground and protect soils from soil erosion.
• Improved ground cover contributes to reduce soil erosion,
particularly when species with spreading growth habits are used
as intercrops (Stoop, 1986).
• Alley cropping also helps to check soil erosion (Dharmasena, 1992).

20. 5) Conserve soil moisture
• Water infiltration to the soil and porosity of soil are improved due
to root activity of intercropping.
• The moisture environment immediately below the soil surface is
commonly improved by intercropping (Fukai and Trenbath, 1993),
as the soil surface under an intercrop is not as exposed
as in the sole crops.

21. • Therefore evaporative water loss from the intercropped area is
reduced. Lal (1989) has reported that soil moisture content in the
top 0-5 cm layer in agroforestry systems was generally
higher than that in control plots during both wet and dry
seasons.
• This is due to the reduced soil moisture evaporation and the
effect of shade provided by the intercrop.

22. 6) Efficient utilization of resources to improve
productivity of the land
• The cashew is a seasonal crop.
• It produces fruits once a year usually from March to July in Sri
Lanka (Pushpakumara, 1999).
• The national average yield of cashew is approximately 4-5
Kg/tree/year, which is far below the potential yield (8-10
Kg/tree/year) that obtained by many other countries (Wijeratna and
Jayasekera, 2000).

23. • Therefore productivity of cashew lands is very low when
maintained as monocultures, which is recognized as an inefficient
form of land use, providing low returns to growers.
• The excess land, soil nutrients, moisture and light which are not
used by cashew plants during the early period of cashew can be
utilized efficiently and there by increase productivity of the land.
• Annual food crops when intercropped with newly planted and
two year old cashew received 100% and 89.4% incident radiation
respectively (Abeysinghe 2001).

24. • This is expected because cashew plants are not tall enough to
provide shade during first two years.
• Hence, inter row space of newly planted and two year old cashew
plantations could be used for cultivation of other crops as
intercrops.
• In young cashew plantations, it has been reported that the
unutilized land area is as high as 80-90% (Abeysinghe, 2001).
• Therefore this unutilized land in young plantations could
effectively be utilized to raise intercrops.

25. 7) Create more employment opportunities
• Since cashew is a seasonal bearer, harvesting season is confined
to one to two months per year.
• It requires more Laboures only during harvesting and planting
seasons.
• Due to this reason most of the plantations and small holders use
temporary laboures.
• This creates an excess labour force during rest of the year
specially in cashew growing areas like Puttalam, Anuradhapura
and Hambantota.

26. • By planting intercrops in cashew plantations more employment
opportunities can be created.

27. 8) Provide food for home consumption
• Most of the small holding farmers who are in cashew growing
areas are poor and have limited land to cultivate.
• Hence, planting the field crops as intercrops or mixed planting
with cashew may provide not only an added income, but also
some food for daily consumption

28. Crops suitable for intercropping
with cashew
• Since only the immature period of cashew plantations (eg. first
two to three years) is recommended for intercropping, short term
crops such as annuals and semi perennials can be used as
intercrops.
• It is difficult to recommend a plantation crop or two for
intercropping with cashew.
• Many types of crops can be cultivated as intercrops.

29. • Selection of a crop depends on variety of factors such as, area,
rainfall, temperature, ability of the farmer to cultivate, availability
of planting material, marketing facilities, resources etc.
• The most common annual and semi perennial crops grown during
the immature phase of cashew are as fallows.

30. Annuals
Cereals : Maize, Finger millet (Kurakkan)
Legumes : Cowpea, Mungbean, Blackgrame
Oil seed crops : Soyabean, Groundnut, Sesame (Gingelly)
Vegetables : Bushsitao, Chilli, Brinjal, Okra
Roots & tuber crops: Ginger, Turmeric

31. Selection of crops
• The annuals that are suitable for intercropping with cashew
normally be cultivated as rain-fed crops.
• Hence, suitable intercrops for different agro- ecological zones
and cultivations seasons should be identified.

32. Thank You..