Comparative Study on the Growth and Cadmium Absorption of Three Glutinous Sorghum Varieties under "A Two-Harvests"

  Objective  The purpose of this study was to investigate the absorption and removal effects of three kinds of glutinous sorghum on cadmium-polluted paddy soil.

  Method  "Chuannuoliang1 (CCN-1)", "Xingxiangliang 2 (XXL-2)" and "Jinnuoliang 5 (JNL-5)" were selected as experimental materials. The differences of cadmium absorption in growth and above-ground parts of three kinds of glutinous sorghum and their effects on soil nutrients and soil cadmium content were studied by using "A Two-Harvests" planting method with fallow as control.

  Results  The results showed that the annual straw biomass of XXL-2 was the highest (19,461.0 kg hm⁻²), followed by JNL-5 (19,143.5 kg hm⁻²) and CNL-1 was the lowest (18,982.5 kg hm⁻²). The annual grain yield of XXL-2 was the highest (11887.0 kg hm⁻²), followed by CNL-1 (11527.5 kg hm⁻²) and JNL-5 was the lowest (10929.5 kg hm⁻²). The cadmium absorption of straw and grain of XXL-2 was 15342.0 mg hm⁻² and 186.0 mg hm⁻², respectively. The annual cadmium absorption of straw of XXL-2 was significantly higher than that of CNL-1 and JNL-5. There were no significant differences in Cd content, soil pH and available Cd content between the first and regenerated seasons of 3 glutinous sorghum varieties.

  Conclusion  The results showed that the planting mode of glutinous sorghum with "A Two-Harvests" in slight cadmium-polluted paddy fields was a reproducible and popularizing management mode, which could provide technical support for regional heavy metal control. In addition, xxl-2 was a more suitable variety for promotion in this area.