title: Sewage sludge as an initial fertility driver for rapid improvement of mudflat salt-soils.
abstract: Sewage sludge is by-product in the process of centralized wastewater treatment. Land application of sewage sludge is one of the important disposal alternatives. Mudflats in the interaction zone between land and sea can be important alternative sources for arable lands if amended by large amount of organic fertilizers. Rich in organic matter and other nutrients, sewage sludge has been considered as the economic choice for an initial fertility driver. However, sewage sludge amendment has been greatly hampered due to availability of potential toxic metals. Using sewage sludge in compliance with the national standards for agricultural usage could avoid the accumulation of heavy metals. Nevertheless, it is not clear whether massive input of sewage sludge would increase heavy metals concentration in crops. The objective of this study was to investigate impact of sewage sludge amendment (SSA) as an initial fertility driver by one-time input, with the rates of 0, 30, 75, 150, and 300tha-1, on biomass of green manures, soil chemical properties, and growth and heavy metals uptake of maize (Zea mays L.) grown in mudflat soil. Results showed that one-time sewage sludge amendment promoted an initial fertility for infertile mudflat soil, supported growth of ryegrass as the first season green manure. By tilled ryegrass, it modified the chemical properties of mudflat soil by increasing soil organic carbon, total and available N and P, and decreasing soil salinity and pH, which promoted subsequent growth of two green manures for sesbania and ryegrass. The sewage sludge as an initial fertility driver combined with planting and tilling green manures, increased dry matter of the aerial part and grain yield of maize grown in mudflat soil. Cd and Ni concentrations in grain of maize were positively correlated with sewage sludge amendment rates. Importantly, heavy metal concentrations in grain of maize at all SSA rates did not exceed the safety standard for food in China (GB 2762-2012). The study suggests that sewage sludge can be applied as an initial fertility driver for mudflat soil amendment, which provides an innovative solution for arable land resources and solid waste disposal.
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China; Institute of Agro-biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Bai
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Zang
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
authors.forename: Minjing
authors.initials: M
authors.lastname: Gu
authors.affiliation: Department of Geology, Appalachian State University, Boone, NC 28608, USA.
authors.forename: Chuanhui
authors.initials: C
authors.lastname: Gu
authors.affiliation: Institute of Agro-biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China. Electronic address: shaohongbochu@126.com.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Shao
authors.affiliation: Jiangsu Cultivated Land Quality and Agro-Environment Protection Station, Nanjing 210036, China.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Jiangsu Cultivated Land Quality and Agro-Environment Protection Station, Nanjing 210036, China.
authors.forename: Xukui
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhou
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China. Electronic address: shanyuhua@outlook.com.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Shan
authors.affiliation: College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Feng
mesh_terms: D002681:China; D005308:Fertilizers; D019216:Metals, Heavy / Q000378:metabolism; D054712:Salinity; D012722:Sewage; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000378:metabolism; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism
chemical_list: D005308:Fertilizers; D019216:Metals, Heavy; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants
keywords: Green manure; Heavy metals; Mudflat salt-soil improvement; Sewage sludge; Soil amendment