Combined effects of water retaining agent and green manure on trace elements concentration in tobacco farming purple soils

Green manure (GM) is widely adopted for agricultural productivity and sustainability. The present study supplemented the GM effect with that of water retaining agent (WRA) to enhance sustainability tobacco planting purple soils in Sichuan Province, China. employed three legumes varieties (Trifolium repens, Vicia villosa Medicago sativa), while WRA used was polyacrylamide at different application rates (0, 30, 90, 150 210 kg/ha). results revealed average concentration trace elements ranged from 0.86 1.18 mg/kg, 22.2 26.5 g/kg, 78 426 16 to19 69 76 mg/kg Mo, Fe, Mn, Cu, Zn, respectively. Compared actual soil concentration, Mn increased by adding or kg/ha M. sativa fertilized soil. Zn combining any rate V. T. repens. combination 90 sativa, 30 either repens decreased Fe. Then, all treatments reduced Mo Cu. Therefore, these affected environmental conditions associated responses individual elements. Key words: manure, agent, soil,