| Cichorium intybus L.and Pennisetum clandestinum Hochst.ex Chiov.are perennial plants,which are mostly used as high quality feed for animal husbandry because of their rich nutritional value.Both silicon and selenium can promote plants growth and alleviate various environmental stresses.In recent years,it has been widely reported that the silicon and selenium fertilizer application alleviate the toxicity of soil pollutants to plants.In this study,pot experiments were conducted to investigate the effects of silicon and selenium fertilizer application on the growth and elements absorption of forage in multi-contaminated soil.Thus,this study aims to screen out effective fertilization methods and provides a theoretical basis for forage cultivation.Experiment 1 Effects of silicon fertilizer application on chicory growth and element absorption in multi-contaminated soil.This experiment set five treatments:control（CK）,two soil application levels of 0.5 g Si kg-1(Sis1),1.0 g Si kg-1(Sis2)and two foliar spray levels of 0.3 g Si L-1(Sif1),0.6 g Si L-1(Sif2).The results are as follows:（1）Sis1and Sis2treatments had significant effects on the shoot biomass,shoot Cd,Pb and Zn concentrations of chicory and soil p H.Compared with CK,Sis1and Sis2treatments increased shoot biomass by 5.70 times and 7.00 times,increased p H by 0.69 units and 1.10units,and decreased shoot Cd,Pb and Zn concentrations by 68.25%,69.70%,74.67%and88.88%,69.70%,90.99%,respectively.However,the shoot biomass,shoot Cd,Pb and Zn concentrations and soil p H were not remarkably affected in Sif1and Sif2treatments.（2）Soil application and foliar spraying treatments had the same effect on the absorption of pollutant by chicory.The shoot Cd,Pb and Zn concentrations reduced with the increase of silicon fertilizer application.Experiment 2 Effects of silicon and selenium fertilizer alone or in combination on the growth and elements absorption of kikuyugrass in multi-contaminated soil.This experiment had ten treatments:control（CK）,three soil application levels of 1.0 g Si kg-1（Sis）,10 mg Se kg-1（Ses）,1.0 g Si kg-1+10 mg Se kg-1（Sis+Ses）and three foliar spray levels of 0.6 g Si L-1（Sif）,6.4 mg Se L-1（Sef）,0.6 g Si L-1+6.4 mg Se L-1（Sif+Sef）and three soil application combined with foliar spray levels of 0.5 g Si kg-1+0.6 g Si L-1（0.5 Sis+Sif）,5 mg Se kg-1+6.4 mg Se L-1（0.5 Ses+Sef）,0.5 g Si kg-1+5 mg Se kg-1+0.6 g Si L-1+6.4 mg Se L-1（0.5[Sis+Ses]+[Sif+Sef]）.The results are as follows:（1）Sisand 0.5[Sis+Ses]+[Sif+Sef]treatments had a positive impact on shoot biomass,total biomass,plant height and soil p H.Compared to CK,Sisand 0.5[Sis+Ses]+[Sif+Sef]treatments increased shoot biomass,total biomass,plant height and p H by 43.63%,30.97%,25.19%,1.23 units and 38.79%,30.98%,25.76%,0.74 units,respectively.0.5 Sis+Siftreatment notably increased shoot biomass,plant height and soil p H.In contrast,Sisand Sis+Sestreatments indicated a reduction in root biomass was 39.18%and 67.44%,respectively.Additionally,there were no significant differences in biomass,plant height and soil p H between Ses,Sif,Sef,Sif+Sefand 0.5 Ses+Seftreatments.（2）Different treatments had no significant influence on As and Cu concentrations in shoot.Sistreatment had significant effects on Cd,Pb and Zn concentrations in the shoot,which were 22.06%,46.17%and 80.70%lower than those of CK,respectively.Ses,Sif,Sif+Sefand 0.5 Sis+Siftreatments significantly reduced the concentration of Pb and Zn in the shoot.In addition,shoot Zn concentration was significantly decreased in Sis+Ses,Sef,0.5 Ses+Sefand 0.5[Sis+Ses]+[Sif+Sef]treatments.In summary,soil application of 0.5 g Si kg-1and 1.0 g Si kg-1could significantly increase shoot biomass of forage and soil p H value,while significantly decrease the concentration of Cd,Pb and Zn in the shoot of forage,thereby effectively alleviating the pollutants toxicity on forage.However,the application of selenium fertilizer did not markedly affect the growth and element absorption of forages. |
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