Plant metal concentrations in Theobroma cacao as affected by soil metal availability in different soil types

Efecto del pH sobre la concentración de nutrientes en cacao (Theobroma cacao L.) en la Amazonia Colombiana

“…La concentración de Fe, Mn, Zn y B en orden descendente para los tres tejidos fue hoja>cáscara>grano, mientras Cu, se almacenó en grano>cáscara>hoja. Lewis et al (2021) reportaron una correlación positiva entre la disponibilidad de Fe, Mn y Zn en el suelo y las cantidades acumuladas en hojas de cacao. En este orden de ideas, las hojas presentaron mayor concentración de micronutrientes y salvo de Cu; en contraste, el grano concentró mayor Cu y la cáscara presentó la menor concentración de Fe.…”

Effect of soil characteristics on cadmium absorption and plant growth of Theobroma cacao L. seedlings

“…However, other factors may also affect the absorption and accumulation of Cd in plants, such as competition with another metal ion, especially divalent ions, such as Zn, 18,27,58 Ca 52 or Mn. 54 Other studies have analysed between four or a maximum of 10 soil variables with available and foliar Cd, 18,22,[25][26][27]57 including pH, electronic conductivity, texture, cation exchange capacity, organic matter, clay and sand contents, and N, C, Zn, Fe, Mn, Ca, Mg, Ni and P, although they have failed to evaluate other variables important for the interaction between the soil and plants and the bioavailability of heavy metals and their absorption such as bulk and real density, porosity, moisture retention, and K, Na, S and Cu. In total, 21 soil variables were analysed in the present study, and there is agreement with some investigations reporting pH to be the most crucial factor involved in Cd availability.…”

“…Some studies report Cd concentrations in soils of between 0.50 and 3.74 μg g −1 in different areas of the country. 17,18 Many studies have shown that edaphic characteristics determine the availability of Cd in the soil, with pH, cation exchange, total organic matter, 15,[18][19][20][21][22] dissolved organic matter, 23 macronutrient content and type of clays having an important influence on availability. 4,24 In addition, physical characteristics such as porosity, texture, real and bulk density, and temperature also have effects.…”

“…19,24 The absorption of Cd by plants also depends on the soil's physical and chemical characteristics; for example, pH, cation exchange capacity, organic matter and calcium (Ca) concentration have been reported as important variables in the process of Cd absorption. 5,18,22,25 Even farm management practices can affect Cd uptake. 26,27 Available Cd is usually a good predictor of Cd absorbed by cacao plants.…”

“…26,27 Available Cd is usually a good predictor of Cd absorbed by cacao plants. Studies have been conducted with several extractants, such as ethylenediaminetetraacetic acid (EDTA), Melich 3, diethylenetriaminepentaacetic acid (DTPA), ammonium bicarbonate (AB)-DTPA and HCl, 22,28,29 in which correlation coefficients between available and foliar Cd ranging from 0.37 to 0.82 have been reported. By contrast, the total Cd content in the soil generally represents less than 50% of the variance of Cd uptaken by the plant; therefore, total Cd of the soil is a limited predictor of Cd absorption in crops.…”