猪粪中铜、锌与等量水溶性盐对两种叶类蔬菜的植物有效性比较

Phytoavailability comparison of Cu and Zn in two types of leaf vegetables after application with manure and their equivalent water-soluble salts

选取潮棕壤、红壤和灌漠土为试验用土,采用盆栽试验研究了猪粪中重金属Cu、Zn对空心菜和小白菜的植物有效性,并与添加等量Cu、Zn水溶性盐的植物有效性进行了比较。结果表明:当猪粪施用量为50 g·kg^(-1)时,空心菜地上部Cu、Zn含量均低于等量水溶性重金属盐的处理。猪粪中Cu、Zn在潮棕壤、红壤和灌漠土上种植的空心菜的植物有效系数分别为48.95%、89.77%、67.81%和22.40%、10.1%、54.24%,在第二季作物小白菜上的植物有效系数较空心菜均有较大幅度的提高,分别为91.38%、135.97%、128.32%和59.06%、15.23%、99.94%。当猪粪施用量为100 g·kg^(-1)时,三种土壤上空心菜和小白菜地上部Cu含量均高于等量水溶性Cu盐处理。猪粪中Cu的植物有效系数均大于100%,而Zn有效性系数除个别处理外,均低于100%。猪粪中Cu、Zn有效性系数总体呈现随施用量增加、施用时间延长而显著升高的趋势。此外,猪粪中Cu、Zn的植物有效系数在三种供试土壤之间亦有明显差异,猪粪中Cu有效系数为红壤>灌漠土>潮棕壤,Zn有效系数则为潮棕壤>灌漠土>红壤。综上,施用猪粪增加了空心菜和小白菜地上部Cu、Zn的含量。

Pot experiments with aquic brown soil, red soil, and irrigated desert soil as experimental soils were conducted. The phytoavailabil-ities of Cu and Zn in pig manure for water spinach（Ipomoea aquatica）and pakchoi（Brassica chinesis）were determined and subsequently compared with their equivalents in water-soluble salts. As the pig manure application reached 50 g·kg^（-1）, the contents of Cu and Zn in water spinach shoots were lower than those of the treatment with their equivalent water-soluble salts. The phytoavailability coefficients in aquic brown soil, red soil, and irrigated desert soil were 48.95%, 89.77%, 67.81% respectively, for pig manure Cu and 22.40%, 10.1%, 54.24%,respectively, for Zn. The phytoavailability coefficients of pig manure Cu and Zn for pakchoi were significantly improved compared with those for water spinach, which were 91.38%, 135.97%, and 128.32%, respectively, for Cu and 59.06%, 15.23%, and 99.94%, respectively, for Zn. As the pig manure application reached 100 g·kg^（-1）, the contents of Cu in water spinach and pakchoi shoots were higher than those of the equivalent water-soluble Cu salts. The phytoavailability coefficients of Cu in pig manure were higher than 100%, while those of Zn were less than 100%, except in aquic brown soil. The phytoavailability coefficients of Cu and Zn increased with application dose and time. Furthermore, the phytoavailability coefficients of Cu or Zn were different among the three experimental soils. Cu phytoavailability coefficients were in the order of red soil, irrigated desert soil, and aquic brown soil from high to low, and those for Zn in the order of aquic brown soil, irrigated desert soil, and red soil from high to low. The results indicated that the application of pig manure significantly increased the contents of Cu and Zn in water spinach and pakchoi shoots compared with the control.