The cashew tree (Anacardium occidentale) originates from South and Central America. Cashew nuts consist of 35-45% seeds and around 55-65% shells. The shells contain 15-30% oil. A ton of nuts contains around 200kg seeds and 180kg oil. Cashew nut oil or Cashew Nut Shell Liquid (CNSL) is used as oil in industry. Cashew nuts are dried before being sold. The cashew apple can be sold fresh as soon as they have been picked, and then used as a culinary ingredient, or further processed into drinks (juice, wine), marmalade or vinegar. In India, rubber is sometimes harvested from the trunk, and used instead of rubber arabicum.
Due to the wide variety of ecological sites for cashew trees, general recommendations can be offered for diversification. It is possible to develop a multitude of combination possibilities for each and every site, which include local tree and bush species for agroforestry systems.
Crops such as hibiscus, peanut, dry rice, sesame, beans and soya beans, as well as various vegetable crops can also be planted. Ricinus (Ricinus communis) is also possible, whereby this plant can be integrated as a green fertiliser.
Pineapple can be included among the crops mentioned above, as a secondary plant among the bottom crops.
Mangoes, as fruit trees, are suitable partners in a cashew garden. It should be noted that both grow to roughly the same height and also have widely-spreading crowns, therefore, they need to be planted at a sufficient distance from one-another. Crops that could be planted as middle crops include Annonaceae ssp. (Annona squamosa L.), as well as guavas (Psidium guajava L.), as they thrive in the shade of cashew nut trees.
Arable fruits can also be planted between the rows, especially in young cashew gardens. Intensity, species and crop rotation are dependent on the specific site conditions and the market access for each crop. In West Africa, good results have been gained from using peanuts and soya beans as bottom crops. Grains and arable fodder crops are also possibilities. The bottom crops need to be integrated within a crop rotation system.
Under no circumstances should the system lack palm trees. The wide variety of different regional species on the planet makes it slightly difficult to offer any recommendations here. Even when no commercially viable varieties are available within the region, palm trees are generally excellent suppliers of building materials and fuel.
Crop cultivation and maintenance
Young cashew trees should be trimmed in the first 3-4 years to develop enough fruits growing laterally to the main stem. Afterwards, no further trimming is necessary. When branches reach down to the ground, or older trees are too widely spread, then a regeneration cutting should be performed. Dead branches should be regularly removed. In order to ease harvest work, tree grids with a diameter of 2-4m should be previously covered with mulching material.
Harvest and post-harvest handling
If the cashew tree apple is to be used, the ripened fruits need to be harvested twice a week. The fruits are taken to the processing site, where the nuts are separated from the rest of the fruit. If the apples are not to be used, then picking up the fallen nuts once per week is sufficient. The apple parts are then cut away from the nuts and left out on the site.
The processing method used depends on the amount of nuts harvested: if fewer than 10 tons of raw nuts have been harvested, then no special equipment is needed to roast them, and the nuts can be shelled by hand.
Between 10-50tons, the nuts can be processed with simple tools. The nuts can either be dry-roasted, or in a bath of CNSL.
The following is a list of quality characteristics with minimum and maximum values for cashew nuts that are usually required officially or by importers. Different minimum and maximum values can be agreed between importers and exporters, providing these do not clash with official regulations. Quality characteristics Quality characteristics Minimum and maximum values Appearance Specific, according to the quality Taste and smell According to the variety, fresh, not rancid, not stale Purity Free of foreign matter (sand, stones, shell parts, insects etc). Water content Max. 5.0% Peroxide value Max. 1.0milli-equivalent of peroxide per kg fat Free fatty acids Max. 0.7% Residues Pesticides Not measurable Bromide and ethylene oxide Not measurable Heavy metals Lead (Pb) Max. 0.50mg/kg Cadmium (Cd) Max. 0.05mg/kg Mercury (Hg) Max. 0.03mg/kg Micro-organisms Total number of parts Max. 10.000/g Yeasts and fungus Max. 500/g Enterobacteria Max. 10/g Coliforms Max. 10/g Escherichia coli Not measurable Staphylococcus aureus Max. 100/g Salmonella Not measurable in 25g Mycotoxins Aflatoxin B1 Max. 2 Vg/kg Total aflatoxins B1, B2, G1, G2 Max. 4 Vg/kg
To have quality requirements and no contamination of the cashew nuts, preparation should take place under clean, hygienic and ideal conditions, such as:
- Equipment (tubs, knives etc.), as well as working and drying surfaces (racks, mats etc.) and preparing and storage rooms, should be cleaned regularly.
- Personnel should be healthy, and have the possibility to wash themselves or at least their hands (washrooms, toilets) and wear clean, washable clothes.
- Water used for cleansing purposes must be free from faeces and other contaminants.
- Animals or animal faeces must not come into contact with the product.