Intercropping is a common practice in Africa, but the advantage compared to sole cropping depends on the crop plants and local agro-ecological conditions.
In Rwanda, maize has been intercropped with other legumes such as common beans or soybeans. Intercropping of maize with watermelon is new, and it is used where the availability of land is limited to optimally utilize the available land. Watermelon has emerged as a high-value crop that can replace traditional companion crops in maize cultivation due to high demand in the local market.
The technology is applied by planting maize at 0.25 meters within the rows and 1.0 meter between rows. Watermelon is planted at 1.0 meter between individual watermelon plants. The ‘Sugar Baby’ variety of watermelon, grown in these areas, takes 120 days to mature. It produces melons with bright red flesh. This means that both maize and the watermelon are harvested around the same time.
Watermelons like loamy, fertile, well-drained soil. Using a hoe, form mounds of earth (hills) to plant seeds in. Place 3 or 4 holes into the soil with a tool or your finger, about 2.5 cm deep. Place 1 to 4 seeds in each hole, then rake the soil flat over the top of the seeds and lightly press the soil to pack it sufficiently to keep the moisture from quickly evaporating around the seed. Plant the seed directly into the ground.
The major limitation for which farmers detest this technology is that both maize and watermelon take a lot of nutrients from the soil that need to be replaced periodically. Since watermelon, unlike beans and soybeans, requires spraying, the profitability of this technology may be reduced by these input costs. Furthermore, there are several varieties of watermelon that may perform differently in different soils and have different preferences by consumers. So, there is a need to evaluate the market potential of this technology.
Major Benefits of Intercroppong
- Increased income
- Employment
- An additional food source
- Minimization of production risks
- Reduction of production costs by having many fields
- Increased resilience and income security
- Watermelons provide soil cover while maize provides shade to the melons
Intercropping as an Effective Strategy
Intercropping is an effective farming strategy that enhances land use efficiency, improves soil fertility, and maximizes economic benefits. One of the most productive combinations is intercropping maize with watermelon, as it optimally utilizes available resources while reducing pest infestations and promoting biodiversity. Implementing this strategy requires proper planning, from selecting suitable land to effective crop management, to achieve high yields and sustainable farming.
Land Selection and Preparation for Planting Corn and Watermelon
Selecting the right type of soil is crucial for the success of intercropping maize and watermelon. The ideal soil should be well-drained and fertile, with a pH ranging between 6.0 and 7.0. Loamy or sandy loam soils work best due to their superior water retention capacity and rich organic matter content.
The first step in land preparation involves clearing the field of weeds, crop residues, and debris. Ploughing and harrowing are essential to create a fine seedbed that enhances root penetration and water infiltration. This preparation ensures optimal growth conditions for both maize and watermelon.
Optimal Planting Season - When is the best planting time
Timing is critical when intercropping maize and watermelon. The best season for planting is at the beginning of the rainy season. This timing ensures a consistent water supply, reducing the need for irrigation and enhancing germination rates for both crops.
Step-by-Step Guide to Intercropping Maize and Watermelon
- Planting Maize
Maize should be planted first, as it establishes a structured canopy that provides shade and support for the watermelon vines. The recommended spacing for maize is 75 cm between rows and 25 cm between plants. This arrangement allows adequate sunlight penetration and airflow, reducing competition for nutrients. - Planting Watermelon
Watermelon should be planted approximately two weeks after maize. This delay prevents the watermelon vines from overshadowing young maize plants. The recommended spacing for watermelon is 2 meters between rows and 1 meter between plants. Proper spacing ensures sufficient room for vine expansion and fruit development.
Crop Management Practices
Successful intercropping requires efficient crop management. Regular weeding is necessary to prevent competition for nutrients and water. Farmers should apply organic or chemical fertilizers based on soil nutrient needs. Ensuring adequate water supply through rainfall or supplementary irrigation is also crucial for healthy crop growth.
Pest and Disease Control
Intercropping maize and watermelon naturally reduces pest infestations by promoting biodiversity. However, regular monitoring is essential to detect any signs of pests and diseases early. Farmers should implement integrated pest management (IPM) techniques, such as biological controls and organic pesticides, to minimize chemical use while maintaining healthy crops.
Harvesting
Maize is ready for harvest when the cobs are dry, typically after 90-120 days, depending on the variety. Watermelon, on the other hand, is harvested when the fruits are fully ripe, usually 75-100 days after planting. Proper harvesting techniques ensure high-quality produce and maximum returns for farmers.
Additional Intercropping Options in Maize Farming
In many African countries, maize is commonly intercropped with legumes such as beans, pigeon peas, cowpeas, groundnuts, and soybeans. These crops complement maize growth by fixing nitrogen into the soil, enhancing fertility. Legumes should be planted during the first weeding stage to avoid competition with young maize plants.
Apart from legumes, other crops such as potatoes, cassava, and pumpkin have been intercropped with maize with varying levels of success. These combinations offer additional food security and economic benefits for farmers.
Pest Control Benefits of Intercropping
Intercropping maize with legumes and other crops plays a crucial role in pest control. Beans and squash, for instance, attract beneficial insects that prey on common maize pests, including leafhoppers, stalk borers, and fall armyworms. Canavalia species have been found to improve soil productivity when intercropped with maize, further enhancing yields.
A well-known intercropping strategy is the push-pull system, where Desmodium (Desmodium uncinatum) and molasses grass (Melinis minutifolia) are planted between maize rows. These plants emit chemicals that repel stem borer moths, preventing infestations. Desmodium also suppresses Striga hermonthica, a parasitic weed that affects maize growth.
Similarly, Napier grass (Pennisetum purpureum) and Sudan grass (Sorghum vulgare Sudanese) serve as trap crops for stem borers. Napier grass exudes a gum-like substance that traps larvae, preventing damage. These grasses also attract natural enemies such as ants, earwigs, and spiders, which help control pest populations.
Alternative Uses of Maize in Mixed Cropping Systems
Beyond intercropping for increased yields, maize can be used in mixed cropping systems to enhance the productivity of other crops. For example, planting maize in single rows between vegetables provides shade in regions with intense sunlight, improving vegetable yields. Additionally, maize plants serve as natural support structures for runner beans, which can be cultivated for local consumption or export.
Conclusion
Intercropping maize and watermelon presents a powerful strategy for maximizing land productivity, improving soil fertility, and enhancing economic benefits. By following best practices in land preparation, planting, and crop management, farmers can achieve high yields while promoting biodiversity. Furthermore, integrating additional crops, such as legumes and pest-repelling plants, enhances sustainability and long-term soil health. As a result, intercropping stands out as an efficient, low-input, and high-yield farming technique that ensures food security and economic stability for farmers worldwide.
Reference:
https://qcat.wocat.net/af/wocat/technologies/view/technologies_2872/
Further reading
What is intercropping and why is it better than monoculture?
