污泥施用量对滨海盐渍土肥力的改良效果

摘要

The sewage sludge produced from Bailonggang wastewater treatment plant was collected as fertilizer to improve the fertility of alkaline soil in coastal area.Compared with the control group,soil pH was decreased with different degree during the whole experiment.The highest pH drop (4.79％) was found in group applying 2.5％(wt％) of composting sludge in alkaline soil,after one years of application,the soil pH was decreased by 0.41 unit.There had no significant difference on soil pH in other treatment groups (P＞0.05).After fertilizing the sewage sludge,the soil electrical conductivity (EC) still below the limit value (1.3mS/cm) for plant normal growth,indicating that the salt content of sludge was not the limiting factor of sewage land use.Application the composting sludge for one year,the soil organic matter (SOM),including alkali-hydrolysable N,available P,TN,TP and TK all increased to different degree except available K.The soil bulk density had a slightly downward trend after fertilizing composting sludge,illustrated that the composting sludge could improve the soil structure to a certain extent.The influence of composting sludge on soil bulk density was also depended on the fertilizing quantity.%以白龙港污水处理厂产生的生活污泥为研究对象,采用田间试验开展了污泥土地利用对滨海盐渍土肥力改良效果的研究.结果表明:(1)与对照处理相比,施用熟化污泥后,在整个试验过程中,土壤pH均可不同程度降低,其中施用2.5％(质量分数,下同)熟化污泥的处理,一年后与对照处理相比,pH降低了0.41个单位,降幅达到4.79％,而其他处理间差异不显著(P＞0.05).各处理的土壤电导率(EC)均在植物正常生长限值(1.3mS/cm)内,表明熟化污泥中盐分含量不是其土地利用的限制因子.(2)熟化污泥施用土壤一年后,除速效钾外,均可不同程度增加土壤中有机质(SOM)、碱解氮、有效磷、全氮、全磷、全钾含量.(3)施用熟化污泥后,土壤容重总体有略微下降的趋势.这说明,熟化污泥可在一定程度上改善土壤结构,但不同的污泥施用量,对土壤容重影响程度不同.