关键词: 钾肥, 大白菜, 莴苣, 重金属, 硝酸盐

Abstract: 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.

Key words: Potash fertilizer, Chinese cabbage, Lettuce, Heavy metal, Nitrate