Why you should practice intercropping

By Maureen Kamore

Farmers are encouraged to practice intercropping as it not only helps in effective utilization of land but also facilitates better utilization of soil moisture and nutrients. Other reasons for intercropping include: repelling pests, reducing weeds and providing nutrients for the neighbouring crops.

Intercropping offers smallholder farmers the opportunity to use the same land available and yield more as well as diversify their produce. In addition, the family is able to enjoy a variety of nutrients from the farm, compared to monocropping, where the farmer only grows stapple crops depriving the family of other types of food that would ensure supply of nutrients and a balanced diet in meals. As the planting season approaches, you can plan to practice any of the following types of intercropping to enjoy the benefits mentioned above.

Different types of Intercropping

In deciding which crops to intercrop, farmers should consider their density, required period of maturing, irrigation needs  of each crop, as well as sunlight and nutrients needs.

1. Mixed cropping

Mixed cropping involves planting two or more plants simultaneously in the same field, with no distinct arrangement so that they grow together and can be harvested together. Mixed cropping is best suited for small-scale farming where harvesting is done by hand. Mixed intercropping helps in additional protection to the primary crop against adverse weather. The following crops can be intercropped in this way:

• cashews, coconuts and mangoes 
• cassava and bananas
• maize, sorghum, millets and sesame
• vegetables and legumes such as cowpeas, pigeon peas and green grams 
• cotton with legumes

 2. Row cropping

It’s the growing of two or more crops at the same time alternated in rows. It allows for substantial interspecific interactions, such as shading, root mingling, and competition for water and nutrients. Crops that would do well in row cropping include cereals with legumes, for example maize and beans. The benefit here is additional nitrogen fixing by legumes benefitting the cereal.

Other common combinations include: 

• tomatoes with onions
• tomatoes with brassicas
• cabbage or kale with lettuce 
• cabbage or kale with onions

Relay intercropping
Is planting a second crop type into an existing standing crop once it’s reached the reproductive stage. This method of planting reduces temporal overlap in harvesting different species. When choosing crops to intercrop in this way, ensure that the second crop is tolerant of the shade of the first one. Crops that are suitable for this method of intercropping include maize and cotton, or chick peas and rice, in upland areas. Other examples are:

• maize and soybean
• maize and sweet potato

4. Alley intercropping

Is the cultivation of food, forage or any other crops between rows of trees. Higher plants protect the lower ones from winds and shelter from extra sunlight as well as prevent soil erosion with their vigorous root systems.

5. Trap intercropping

Is the planting of a trap crop to protect the main crop from a certain pest or several pests. A trap crop is a plant that attracts agricultural pests, usually insects, away from nearby crops. Examples of plants used for trapping pests include marigold and mustard. The trap crops attract the pests and fungi, drawing them away from the value crops in the farm.

6. Strip intercropping

Strip intercropping is similar to row intercropping but in strip intercropping, a close-growing crop is alternated with one that leaves a considerable amount of exposed ground. This can be practiced by large scale farmers as it allows for machine operation. Examples of crops that are intercropped in this way include wheat, maize and soya beans.

7. Push-pull technology

Push–pull technology is an intercropping strategy for controlling agricultural pests by using repellent “push” plants and trap “pull” plants. For example, cereal crops like maize or sorghum are often infested by stem borers. Grasses planted around the perimeter of the crop attract and trap the pests, whereas other plants, like Desmodium, planted between the rows of maize, repel the pests and control the parasitic plant striga.

Fig 01: Maize push-pull technology showing intercrop strategy

 Suitable Intercropping Combinations

Crop	Intercrop with
Tomato	Onion family, Carrots, Asparagus
Maize	Desmodium, Napier grass
Spinach	Beans, Strawberry
Pumpkins	Corn, Beans
Potato	Cabbage, Beans, Corn
Asparagus	Basil, Tomato, Parsely
Celery	Onion, Cabbage, Tomato
Carrots	Radishes, Lettuce, Tomato, Nasturtium
Onion family	Beets, Carrots, Lettuce, Cabbage family
Parsely	Tomato, Asparagus

The idea of intercropping is for crops to complement each other in growth. When intercropping consider the following:

• The height of the crops; tall crops should shelter ground, bushy crops from excessive sunlight.
• Shallow rooted crops should be intercropped with deep rooted crops to avoid competition for nutrients.
• Crops that require heavy irrigation such as cabbages should not be intercropped with crops that are affected by too much water.
• Crops selected should be of different families to avoid overpopulation of various pests and diseases.

Advantages of Intercropping

• Plant diversity creates overall plant health.
• Greater income due to increased yields.
• Reduction in chemical/fertilizer application.
• The fertility of the soil is maintained.
• Optimum utilization of resources.
• Trap cropping for pest control.
• Maximum utilization of nutrients present in the soil.

• A complementary sharing of plant resources, such as Nitrogen from N fixing plants.
• Weed suppression and a reduction in susceptibility to insects and disease.

Disadvantages of intercropping

• When maturity time differs, sometimes harvesting becomes difficult.
• Some intercrops might be alternate hosts for certain pests, contributing to higher infestation.
• Controlling pests and diseases takes more efforts in intercropped farms.
• It is labour intensive and using farm machines may be difficult.
• Allelopathic effect where one organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms, may have adverse effects on intercropped plants.

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