Influence of organic and chemical fertilizers on tomato yield, quality, and the content of available heavy metals in soil.

In this study,a series of experiments were conducted to investigate the influence of organic and chemical fertilizers on the yield,quality of tomato(Solanum lycopersicom L.)and on the content of available heavy metal elements in tomato fruit and soil.The results showed that incorporated application of organic and chemical fertilizers significantly increased the tomato yield when nitrogen application was identical.The highest total yield of tomato was found in the treatment which combined rate of organic and chemical fertilizer was 6:4,and the total yield increased by 15.6% compared with the control.We found that the contents of soluble sugar and organic acid in fruit increased in chemical fertilizer treatment,but the content of Vc was the highest in the organic fertilizer treatment.Comparatively,the fruit taste and nutritional quality of fruits were the best in organic fertilizer treatment.However statistical results indicated there were no obvious relativity between the content of soluble sugar,organic acid or Vc and the treatments of fertilizer.In addition,the nitrate concentration of fruit was lower in treatment of organic fertilizer than that of in treatment of organic or in incorporated treatment of organic and chemical fertilizer,but the nitrite concentration of fruit was comparatively lower in the chemical fertilizer treatment or in low rate of organic fertilizer treatment.Our study also indicated that(1)In incorporated treatment of organic and chemical fertilizer,the content of Hg in tomato fruits significantly decreased comparing with the control treatment,but the contents of Pb and As increased,meanwhile concentration of Cu,Zn,and Cd in tomato fruits did not have obvious change.In the same treatment,the contents of available Pb decreased;the concentration of available Cr,As did not have obvious change(.2)In treatment of organic fertilizer,content of available Cu in soil was decreased significantly,but content of available Hg decreased.(3)In treatment of chemical fertilizer,the concentration of available Cu in soil could be raised.