Abstract:

In view of the pollution caused by sludge to surrounding environment, in China, the sludge was increasingly made into fertilizer source by single use, composting, organic-inorganic fertilizer, bio-organic fertilizer and so on. Presently, the experimental practices of sludge-originated fertilizer applied to various crops have been increasingly conducted. In this paper, we discussed the efficacy of sludge application and the effect of sludge on soil quality. Published studies show that sludge application can promote growth and development of crops, including germination of seedlings, growth, and their relevant physiological and biochemical indicators, significantly stimulate the nutrition absorption from soil, and improve the grain yield and crop production, as well as crop quality. However, excessive application of sludge may inhibit seed germination rate of some species, while heavy metals accumulation in crops generally meet the national food hygienic standards except few heavy metal species. Sludge is rich in organic matter, various macro-medium and trace mineral elements, heavy metals and organic pollutants, which thereby results in differences for soil quality improvement under different sources, different applying quality and different dosage of sludge. After application, soil quality indicators including organic matter, pH, macro-medium and trace elements, aggregate structure, bulk density, electrical conductivity, soil enzyme and microbial activities, are generally improved. In general, domestic sludge contains heavy metals, organic pollutants and so on, of which heavy metals are unfrequent to exceed the standard of heavy metals. Based on rationale of resources maximal utilization, sludge application should be not only beneficial for the sludge recycled usage but also for non-adverse for environmental pollution. Owing to the content of heavy metals in sludge is much higher than that in soil, that the larger amount of sludge is applied will lead to the higher contents of heavy metals, so it is safer using the appropriate application dosage. This overview draws conclusion that the content of heavy metals can meet the pollutant control standard of agricultural waste things, but not for few heavy metal species. If it is properly treated, sludge can be used for crop production.

Key words: municipal sewage sludge, crop growth, quality, soil fertility, heavy metal, organic substance, transport

摘要：

为了消减污泥对环境的污染,中国在污泥利用方面采用了多种制肥技术,采用单独使用、堆肥、有机无机肥、生物有机肥等处理方式制成产品,而且在各种农作物上的试验越来越多。文章探讨了污泥施用对作物生长的效果和对土壤质量的影响。研究表明,施用污泥对作物生长发育都有良好的作用,相关的生理生化指标有一定程度提高;明显促进土壤速效养分的吸收,提高收获物产量和生物产量,改善品质。作物重金属的吸收积累量除个别例外都能达到国家食品卫生标准,但污泥施用超过一定量对有些作物品种的种子发芽率有抑制作用。城市污泥富含有机质、大中微量矿物质元素等,但不同来源、不同品质和不同用量的污泥对土壤质量的影响有所差异。土壤有机质、pH、大中微量元素、团粒结构、容重、电导率,以及土壤酶和微生物活性等土壤质量指标有所提高。污泥含有重金属、有机污染物等污染物,一般而言重金属超标是不常见的。按照资源化利用的原则,污泥施用既要有利于消化污泥量又要不造成环境污染,污泥中重金属含量比原始土壤中的高,施用量越多重金属含量也越高,所以在适宜的范围内才是安全的。许多试验证明,重金属含量除某些条件下极个别超出安全指标外,基本都能达到农用污泥污染物控制标准。综合来看,在正确处理下污泥是可以用于作物生产的。

关键词: 城市污泥, 作物生长, 品质, 土壤肥力, 重金属, 有机物, 运移