钾肥对大白菜和莴苣产量、重金属和硝酸盐含量的影响

Effects of Potash Fertilizer on Yields, Contents of Heavy Metal and Nitrate in Chinese Cabbage and Lettuce

采用田间小区试验研究了酸性土壤上两种钾肥不同用量对大白菜和莴苣产量、重金属和硝酸盐含量的影响。结果表明:施用两种钾肥均明显提高了大白菜和莴苣的产量,分别增产9.0%～20.0%和8.7%～52.0%,增产作用最大的处理均为高钾处理〔30kg·(667m2)-1〕。中量硫酸钾配施泥炭(K2S+M)处理较单施硫酸钾处理使大白菜和莴苣显著增产,分别增产14.6%和12.1%。施用钾肥明显降低了大白菜硝酸盐含量,但对莴苣硝酸盐含量以提高作用为主,且随着钾肥施用量的增加呈递减趋势。施用钾肥显著降低了大白菜砷和铅含量,明显降低了莴苣铬含量,对其余重金属的作用不一致。中量硫酸钾配施泥炭处理明显降低了大白菜和莴苣的重金属含量(大白菜汞和莴苣镉除外),提高了蔬菜的食用安全性。

Field experiments were carried out to study the effects of two kinds potash fertilizer with different dosages on yield,contents of heavy metal and nitrate in Chinese cabbage(Brassica campestris L.spp.pekinensis)and lettuce(Lactuca sativa L.)under acidic soil cultivation.Results indicated that two kinds potash fertilizers could significantly increase the yields of Chinese cabbage and lettuce,which reach 9.0 %-20.0 % and 8.7 %-52.0 %.And the maximum yield was at the high potassium level(450 kg·hm-2)for Chinese cabbage and lettuce.Combination of medium potassium sulfate and peat(K2S+M)could markedly increase yields of two vegetables as compared with potassium sulfate which reach 14.6 % and 12.1 %.Potash fertilizers could significantly decrease nitrate content of Chinese cabbage as well improve the content of lettuce.Potash fertilizers could greatly decrease arsenic and lead content of Chinese cabbage as well chromium and lead of lettuce.The effects of potash fertilizers on other heavy metals in two vegetables were discrepancy.Combination of potassium sulfate and peat could significantly decrease the heavy metals content(except mercury in Chinese cabbage and cadmium in lettuce)in two vegetables and improve their food safety.