以广东省佛山市南海区为例,研究了集约化露天菜地表层土壤盐分的累积状况和离子组成,对盐分的季节性消长规律及其变化原因进行了深入分析。结果表明:2006年春季土壤盐分的累积情况较为严重,5个集约化露天菜地样点中有3个样点(1、2、4号)的表层土壤盐分浓度较高,全盐质量分数超过1.0g·kg-1,已达到次生盐渍化的标准,其中又以2号样点(菜场)最为突出,全盐质量分数高至2.42g·kg-1;2006年春季到夏季为脱盐阶段,土壤盐分浓度下降明显;2006年夏季到秋冬季变化幅度不大。土壤盐分浓度的变化与降雨量有密切关系,虽然2006年降雨偏多,但佛山市南海区农业集约化水平较高,部分菜地连年种植蔬菜、复种指数极高、化肥施用量偏大,从而在遇到干旱年份和季节,集约化露天菜地土壤仍有发生次生盐渍化的风险。土壤盐分的离子组成上,阳离子以Ca2+为主,占全盐质量分数的11.0%~24.1%;阴离子以NO3-和SO42-为主,分别占全盐质量分数的8.9%~31.0%和10.9%~45.7%。研究结果可为控制土壤盐分累积、提高蔬菜生产能力及品质、保护和合理利用耕地资源,提供参考资料。 Taking Nanhai District of Foshan City, Guangdong Province as an example, the accumulation status and ionic composition of salinity in the surface soil of intensively cultivated pakchoi were studied. Seasonal changes of salinity and its causes were analyzed in depth. The results showed that the accumulation of soil salinity was more serious in spring 2006. Three samples (1, 2, 4) of the five intensive sampling plots were higher in surface soil and higher in salt content than 1.0g · kg-1, which reached the standard of secondary salinization. Among them, the No.2 sample (farmyard) was the most prominent, with the highest salt content of 2.42g · kg-1; the desalination Stage, soil salinity decreased significantly; summer 2006 to autumn and winter changes range. The change of soil salinity concentration is closely related to the rainfall. Although there was a lot of rainfall in 2006, the level of agricultural intensification in Nanhai District of Foshan City was high. Some vegetable fields planted vegetables in successive years, and the index of multiple cropping was very high. In the dry years and seasons, there is still a risk of secondary salinization of soils in intensive alluvial vegetable fields. The ion composition of soil salinity mainly consisted of Ca2 +, accounting for 11.0% ~ 24.1% of the total salt content. The anions were mainly composed of NO3- and SO42-, accounting for 8.9% ~ 31.0% and 10.9% of the total salt content respectively. ~ 45.7%. The results can provide references for controlling the accumulation of soil salinity, improving the vegetable production capacity and quality, protecting and making rational use of arable land resources.