Phytomanagement of metal-contaminated agricultural land using sunflower, maize and tobacco

We investigated the long-term effectiveness of phytomanagement (the combination of profitable crop production with the gradual reduction of soil contamination by phytoextraction) to deal with moderately metal-contaminated agricultural land. In a 6-year field experiment, we grew maize (Zea mays L.), sunflower (Helianthus annuus L.) and tobacco (Nicotiana tabacum L.) in crop rotation. The addition of elemental sulphur (2136 kg ha−1 yr−1) decreased the soil pH from 7.4 to 6.7, increased the Zn accumulation by maize, sunflower and tobacco by factors of 1.3, 1.4 and 1.2, respectively, and increased the Cd accumulation by tobacco 1.3-fold. Neither the addition of ammonium sulphate (129 kg ha−1 yr−1) nor nitrilotriacetic acid (NTA, 430 kg ha−1 yr−1) significantly increased phytoextraction. The results show that phytoextraction for soil cleansing would require centuries. However, this land could be used to generate profitable crops, including the production of safe (low Cd) stock fodder fortified with Zn, green manure for micronutrient-deficient soils, or bioenergy.