Cocoa Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.
Cocoa Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.
Sci Total Environ. 2019 Nov 25;693:133563. doi: 10.1016/j.scitotenv.2019.07.369. Epub 2019 Jul 23.
Cocoa (Theobroma cacao L.) is an important neotropical tree crop grown for its seeds or beans used in global chocolate and confectionary industries. Following studies showing ill effects of long-term dietary exposure of cadmium (Cd) on human health, a number of countries including the European Union (EU) have developed stringent regulations to protect consumers from exposure to cadmium. Cocoa is capable of bioaccumulating Cd in the cocoa beans when grown in soils high in cadmium and hence livelihood of cocoa farmers can be at risk if methods to mitigate the bioaccumulation of Cd are not developed. In vitro, greenhouse and field experiments were established with four, three and three replications respectively to evaluate the effectiveness of soil amendments, biochar and lime, at various application rates (0, 0.5×, 1×, 1.5× and 2× of the recommended rate), on soil pH, Cd phytoavailability and Cd bioaccumulation in Theobroma cacao L. For the in vitro study, Cd-containing soil was amended with 5 levels of biochar and lime, while for the greenhouse and field study four application rates were tested. The study showed that while lower rates were effective under in vitro conditions as you progressed from in vitro to greenhouse to field conditions the application rates and application frequency had to be increased, as the effectiveness and longevity of the treatments were compromised by environmental factors. Our study implies that the two amendments were complementary in their action and can be used in the recommended rated to reduce Cd bioaccumulation. However further studies are required on the placement of amendments to improve their effectiveness and longevity particularly under field conditions.
可可（Theobroma cacao L.）是一种重要的新热带树作物，因其种子或豆荚而被广泛种植，用于全球巧克力和糖果工业。在研究表明长期饮食暴露于镉（Cd）对人类健康的不良影响后，包括欧盟（EU）在内的许多国家都制定了严格的法规，以保护消费者免受镉的暴露。当可可在高镉土壤中生长时，可可能够在可可豆中生物累积 Cd，因此，如果不开发减轻 Cd 生物累积的方法，可可农民的生计可能会受到威胁。在体外、温室和田间试验中，分别设置了四个、三个和三个重复，以评估土壤改良剂、生物炭和石灰在不同施用量（推荐用量的 0、0.5×、1×、1.5×和 2×）下对土壤 pH、Cd 植物有效性和可可中 Cd 生物累积的有效性。对于体外研究，用 5 个水平的生物炭和石灰对含 Cd 的土壤进行了改良，而对于温室和田间研究，测试了 4 个施用量。研究表明，虽然在体外条件下较低的施用量有效，但随着从体外到温室到田间条件的发展，必须增加施用量和施用量频率，因为环境因素会影响处理的有效性和持久性。我们的研究表明，这两种改良剂的作用是互补的，可以按推荐的用量使用，以减少 Cd 的生物累积。然而，需要进一步研究改良剂的施用位置，以提高其有效性和持久性，特别是在田间条件下。
