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  • Hostile climatic conditions and cashew production in West Africa: how to manage the impact 06/28/2023

    Jun 28th, 2023

    Since its introduction to Africa by Portuguese explorers in the 16th century, cashew has spread across the continent, especially in tropical West Africa. Cultivated to counter desertification and erosion a few decades ago, cashew has now become an important economic product. Today, the cashew industry contributes significantly to the economic growth of several African countries, including Côte d'Ivoire, Guinea Bissau, Benin and Ghana, among others, notably through the creation of jobs and income generation through the export of cashew nuts. The cashew nut grows well in tropical and subtropical regions of the world. This explains why around 60% of the world's Raw Cashew Nuts (RCN) are produced in Africa, with West Africa producing over 45% of the world's cashew nuts. For the average citizen, cashew being resistant to drought, the difficult climatic conditions in West Africa should not affect production. However, African Cashew Alliance (ACA) weekly reports from various West African cashew producing countries, as well as research, have shown that adverse weather conditions affect cashew production. This article examines why weather conditions in West Africa affect the production of cashew, a crop widely known to be drought resistant, and how this can be managed. According to a senior researcher from the Cocoa Research Institute of Ghana (CRIG), Dr. Paul K.K. Adu-Gyamfi, the drought resistance of cashew has been misunderstood. This, he explains, is because for a very long time “the cashew tree was grown as an afforestation crop to provide cover in a marginal environment with no interest in its fruit or nuts” . So there has not been much interest in the yields and productivity of cashew trees. But in recent years, cashew has become an important commodity whose fruits and nuts attract great economic interest. He explains that “the variable yields and survival rates of cashew plants in different ecologies in most West African producing countries suggest that the cashew tree is drought sensitive, although it is more hardy. than other tree crops such as cocoa”. For optimum cashew productivity, a positive combination of several environmental factors is needed. Citing several studies, Dr. Adu-Gyamfi highlighted the importance of the right proportion of rainfall, temperature and dryness required for optimum productivity. “The cashew tree requires an annual rainfall range of 1500 – 2000 mm (Sys et al. 1993) and a temperature range of 25 – 28 ᵒC (Dendena and Corsi 2014) with a pronounced dry period of 5 – 6 months (Dedzoe et al. 2001) for optimal productivity ,” he pointed out. However, due to recent climatic changes, some cashew producing countries are experiencing unfavorable weather conditions for cashew productivity. In Benin, for example, Dr. Joseph TOKORE, program officer (Benin) of the USDA PRO-Cashew project for West Africa and cashew researcher, explains that the average annual rainfall in recent years is between 800 and 1100 mm, which is sometimes lower than the level necessary for cashew trees. The situation is not so different in several cashew producing countries. This situation, together with the high temperature and long drought usually experienced, affected the cashew tree at the most critical stages of production, resulting in poor growth of seedlings during the vegetative phase, leading to a high mortality rate, and by the withering of flowers during the reproduction phase. This therefore affects the growth rate and yield of cashew, An analysis of the relationship between the amount of rainfall and the yield of cashew nuts in Benin for example shows that, although yields do not evolve systematically according to rainfall, a good distribution of rainfall over time is necessary for a good yield and therefore a good production, analyzed Dr TOKORE. Furthermore, the harmattan in Benin and in some West African countries is generally characterized by “a dry wind, cold at night and hot during the day, carrying dust particles from North to East, which contributes strongly to the destruction of cashew flowers”. “In fact, this dust is made up of vegetable particles (grass, dry flowers, pollen), animal particles (bird feathers, waste of all kinds), germs, viruses, parasites and microscopic fungi, which are source of plant and human diseases” , he underlined. MANAGING THE IMPACT OF HOSTILE CLIMATIC CONDITIONS ON CASHEW NUT PRODUCTION For the African Cashew Alliance (ACA), while cashew farmers cannot control weather conditions, they can certainly manage their impact on cashew production. According to doctors Adu-Gyimffi and TOKORE, three key points are necessary in this regard: the use of improved planting material, the increase in soil fertility and the fight against pests and diseases. Through research, improved cashew planting materials have been developed by various agricultural research institutes in West Africa. These improved cashew varieties are not only high yielding and resistant to pests and diseases, but are also, according to Dr Adu-Gyamfi, “tolerant to moisture and temperature stress”. The use of improved grafted clones and recommended seedlings reduces the impact of hostile climatic conditions on production. Also, farmers should increase the soil fertility of their cashew plantations, especially young plantations less than five years old, by using organic manure. This increases the rate of soil moisture retention and helps reduce mortality, especially during the vegetative phase of cashew production in the face of hostile temperatures. Drip irrigation, according to Dr. TOKORE, is highly recommended during the dry season, especially for young cashew plantations in the first two years after planting, to reduce the impact of harsh weather conditions. Because the harmattan in West African countries like Benin carries dust particles that bring pests and diseases to cashew plantations, proper pest and disease control is necessary to reduce the impact on production. This requires adherence to the use of recommended and reliable pest and disease control mechanisms that do not compromise the safety of cashew consumers and have a “minimal effect on the environment”.