Accumulation of Essential Mineral and Toxic Trace Elements in Crops and Soils of Vegetable Cropping Systems in Central Highlands of Sri Lanka

Abstract Background and Aims Vegetables are widely cultivated in high rainfall and mountainous regions in Sri Lanka with poor soil conservation practices. Accumulation of essential mineral and toxic trace elements in these soils and widely cultivated vegetable crops are not known. Methods One hundred soil and vegetable (i.e. cabbage, carrot and potato) samples were collected at the time of harvest and analysed for element concentrations. Key Results Soils contained very high concentrations of essential mineral and toxic trace elements. When compare edible parts, cabbage contained the highest concentrations of mineral and toxic trace elements, and potato contained lowest. Irrespective of the crop, edible parts contained high concentrations of N, P, K, (14-35, 2-6, 15-24 g kg−1, respectively), Cu, Zn, Mn (2.5-6.7, 11-30, 8-147 mg kg−1, respectively). Vegetables also contained As, Cd and Pb (0.04-1, 0.02-0.15, 0.02-0.26 mg kg−1, respectively), but didn’t exceed the maximum permissible limits. Irrespective of the crop 36-64 kg N, 6-11 kg of P, 35-45 kg K per ha were removed with the harvest. According to the current rate of vegetable consumption by a Sri Lankan adult (i.e. 240 g FW per day), per capita consumption of 0.05-0.2 mg Cu, 0.45-0.65 mg Zn and 0.5-2 mg Mn day−1through these vegetables was observed, i.e. 5-23% Cu, 7.5-11% Zn and 22-87% Mn of the recommended daily intake. Conclusion Vegetables grown in the region served as a key source of essential mineral elements. However, agronomic mitigation strategies are needed to improve soil health and sustainability of these cropping systems.