Cashew nut cultivation: the importance of good irrigation

The cashew industry (cashew nut production) is looking promising, thanks to growing global demand. According to the Groupement des industriels du casjou en Côte d’Ivoire (GIC-CI), 2023 was an exceptional year for cashew nut production and processing in West Africa. Raw cashew nut production exceeded 3 million tonnes, representing a significant 23% increase over 2022. (see source)

Innovation and diversification are certainly the keys to a more sustainable and ethical industry. These include genetic improvement, increasing farmers’ performance, adding value to by-products, and modern farming practices such as irrigation and fertirrigation.

Although cashew trees are resilient, judicious irrigation management, adapted to local conditions and the tree’s specific needs, can significantly improve productivity.

Cashew trees prefer well-drained soils. Regular monitoring of soil moisture is essential to adapt water inputs, avoiding both water stress and excess water. Installing capacitive or tensiometric probes in the soil enables you to keep an eye on these parameters in real time.

To promote the development of cashew seedlings, it’s important to adopt a regular watering approach adapted to the specific needs of the plants and environmental conditions.
Careful monitoring of soil humidity will enable you to adjust the frequency and quantity of watering to support healthy growth without risk of water stress (Cashew Nursery Technical Sheet).

Drip irrigation is recommended for cashew nurseries. This method uses pipes with small emitters that deliver water directly to the plant roots. The drip irrigation system is highly efficient because it minimizes evaporation and runoff, thus saving water. Ideal for medium to large nurseries.

Cashew trees’ water requirements vary according to age, soil type and climatic conditions. It is generally recommended to apply moderate doses of fertilizer, avoiding excesses that could saturate the soil and harm the tree. An appropriate net watering dose should be applied, adjusting the frequency according to rainfall and soil humidity.

Remember that the basic principle of drip irrigation is to maintain a moist bulb around the crop roots throughout the irrigation period, preventing it from drying up.

Among the most widely used of these methods are drip and micro-sprinkler irrigation. These two irrigation methods are relatively “water-efficient”.

The choice of one or other of the systems will be the result of technical expertise coupled with consultation on the needs and expectations of the farmer in relation to his irrigated system. In all cases, the design office’s expertise will help define the project’s financial approach, while guaranteeing secure production for the farmer.

Research by the Centre National de Recherche (CNR location: India.), has shown that yields are higher when drip irrigation is chosen. In fact, cashew trees cannot withstand too much water stagnation at root level, which has enabled the CNR to establish the period when it is important to irrigate plants properly.

This extends from flower initiation (becoming a flower bud) to fruit set (initial phase of fruit formation).

Various studies have highlighted the need to use mineral fertilizer to boost cashew nut yields in cashew plantations that are subject to declining soil fertility (Cashew fertilizer data sheet).

Coupled with irrigation, fertirrigation enables nutrients to be applied with great precision according to crop needs. This method has two advantages:

1. It increases a crop’s yield potential through the precise and timely application of nutrients.
2. It reduces the amount of nutrients applied by minimizing leaching and volatilization losses.