A Study on Producing Environment and Product Quality of Typical Organic Agriculture in East China
|School||Nanjing Agricultural College|
|Keywords||organic agriculture heavy metals evaluation soil fertility tea quality|
The top soil and irrigating water in the organic vegetable farm in Shanghai were sampled, in which the heavy metals were analyzed and evaluated. The results showed the single pollution index of As, Cd, Cr, Cu and Pb in the top soil were all less than 1. The combined pollution index of As, Cd, Cr, Cu and Pb was less than 0.7. In the irrigating water, the pollution index of these five heavy metals were all far less than 1, and the combined pollution index were less than 0.5, on clean level. The data indicated that the contents of heavy metals in top soil and irrigating water were up to the standard, the soil and irrigating water in this farm were suitable for organic farming.Through investigated and sampled, the tea and soil quality of organic and conventional tea gardens in Xiuning county and Tunxi county in Anhui province and Lishui county in Jiangsu province were analyzed and compared. For the soil quality aspect, the contents of soil pH, organic matter, total nitrogen, available nitrogen, available P and available K of organic tea garden were all less than conventional’s in Xiuning county and Lishui County. Except soil pH, the other five indexes of organic tea garden soil were 10.8%、76.5%; 18.5%、61.6%; 6.9%、54.6%; 70.8%、36.2%; 3.4%、74.9% less than conventional’s respectively. In Tunxi County, soil pH of organic tea garden were higher than conventional’s. Available K of organic tea garden were 50.4% less than conventional’s. The other four indexes of organic tea garden soil were 16.5%、10.0%、13.6%、151.1% more than conventional’s respectively. In these three areas, available K of organic tea garden were all less than that in conventional one.Meanwhile, it showed that soil quality in organic tea garden were less than that in conventional one in Xiu ning county and Li shui county in this study because of the lack of the fertilizer. Therefore, the fertilizer management of organic tea garden should be strengthened.For the tea quality aspect, the results showed that the contents of water extract,tea polyphenol and caffeine of organic tea were 5.2%、5.4%、4.2% more than conventional’s respectively, but water content、contents of amino acid and soluble sugar were 1.0%、7.8%、0.9% less than conventional’s in Xiuning county. In Lishui County, the water content、water extract and tea polyphenol of organic tea were 1.0%、6.1%、5.3% more than convetional’s respectively, but the contents of amino acid, caffeine and soluble sugar were 8.0%、0.6%、3.5% less than conventional’s. In Tunxi County, the contents of amino acid, caffeine and soluble sugar of organic tea were 5.5%、4.7%、4.9% more than conventional’s respectively, but the water content and content of water extract were 3.4%、0.3% less than conventional’s. In general, contents of water extract,tea polyphenol,caffeine, soluble sugar and the ratio of tea polyphenol to amino acid in organic tea were more than those in conventional tea. The opppsite was that the contents of amino acid in organic tea were less than those in conventional tea. It could be concluded that the brewing sustainability of organic tea was better than conventional ones. Besides, the main chemical constituents that could affect the quality in organic tea were more than those in conventional ones as well as the tea infusion taste, but the tenderness and fresh flavor were worse. According to the comparison of amino acid content of organic and conventional tea in these three areas,the organic tea gardens need to enhance N fertilizer.