Accumulation of Heavy Metals, Yield and Nutritional Composition of Potato (Solanum tuberosum L.) Cultivars Irrigated with Fly-Ash-Treated Acid Mine Drainage

Abstract

This study compared the responses of two potato cultivars, Fianna and Lady rosetta (both determinate and indeterminate), to irrigation with various fly ash: acid mine drainage (AMD) amelioration ratios in two separate seasons. In order to calculate crude protein (CP), the nutritional composition (NC) of potato tuber samples was examined using the combustion method. The results showed that the NC of plants irrigated with AMD mixed with fly ash was significantly affected differently at harvest. In plants exposed to 75% AMD irrigation, the mean moisture content of Lady rosetta was reduced by twice more compared to Fianna. Concisely, our study has demonstrated that irrigation with AMD mixed with fly ash can promote plant growth of potato cultivars and reduce their crude protein (CP) by approximately 4% when irrigated with both 50% FA: AMD and untreated AMD (100% AMD) ratio being applied; nonetheless, it was decreased by 1% when watered with 75% FA: AMD treatment, lipids content, carbohydrates, fresh tuber weight and dry tuber weight. On average, plants from both cultivars irrigated with the 75% AMD had higher fresh tuber weight (FTW), higher dry tuber weight (DTW) and carbohydrates compared to the controls. Furthermore, Lady rosetta cultivar exhibited higher carbohydrate and crude fiber compared to the control at 75 and 50% AMD treatments, respectively. Use of AMD in agriculture is likely to reduce its devastating environmental conditions and assist in irrigation of food crops, thereby alleviating both water and food shortages. Last, all the FA-AMD-treated potatoes had Pb concentrations that were below the minimum standard limits, and this proves that FA was able to adsorb the Pb ions in the tuber samples. Importantly, fly ash reduces a metal’s concentration in AMD. However, presence of heavy metals in such potatoes needs to be explored. It is also important to relate the possible metal intake relative to the standards by World Health Organization (WHO).