Mudflat Soil Amendment By Sewage Sludge: Soil Physicochemical Properties, Perennial Ryegrass Growth, And Metal Uptake

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Chuanhui Gu Ph.D., Assistant Professor (Creator)
Appalachian State University (ASU )
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Abstract: The fast pace of cropland loss in China is causing alarm over food security and China’s ability to remain self-reliant in crop production. Mudflats after organic amendment can be an important alternative cropland in China. Land application of sewage sludge has become a popular organic amendment to croplands in many countries. Nevertheless, the land application of sludge to mudflats has received little attention. Therefore, the objective of the present work was to investigate the impact of sewage sludge amendment (SSA) at 0, 30, 75, 150 and 300 t ha-1 rates on soil physicochemical properties, perennial rye-grass (Lolium perenne L.) growth and heavy metal accumulation in mudflat soil. The results showed that the application of sewage sludge increased organic matter (OM) content by 3.5-fold while reducing salinity by 76.3% at the 300 t ha-1 rate as compared to unamended soil. The SSA reduced pH, electric conductivity (EC) and bulk density in mudflat soil, increased porosity, cation exchange capacity (CEC) and contents of nitrogen (N), phosphorus (P), exchangeable potassium ions (K+), sodium ions (Na+), calcium ions (Ca2+) and magnesium ions (Mg2+) in comparison to unamended soil. There were 98.0, 146.6, 291.4 and 429.2% increases in fresh weight and 92.5, 132.4, 258.6 and 418.9% increases in dry weight of perennial rye-grass at 30, 75, 150, and 300 t ha-1, respectively, relative to unamended soil. The SSA increased metal concentrations of above ground and root parts of perennial rye-grass (p < 0.05). The metal concentrations in perennial rye-grass were Zn > Cr > Mn > Cu > Cd > Ni, and the metal concentrations in roots were significantly higher than above ground parts. The metal accumulation in perennial rye-grass correlated positively with sludge application rates and available metal concentrations in mudflat soil. Land application of sewage sludge was proved to be an effective soil amendment that improved soil fertility and promoted perennial rye-grass growth in mudflat soil. However, heavy metal accumulation in plants may cause food safety concern.

Additional Information

Bai, Y., Tao, T., Gu, C., Wang, L., Feng, K., & Shan, Y. (2013). Mudflat Soil Amendment By Sewage Sludge: Soil Physicochemical Properties, Perennial Ryegrass Growth, And Metal Uptake, Soil Science and Plant Nutrition, vol. 59, issue 6, pp. 942-952. Version of record available from Taylor and Francis [ISSN: 0038-0768], [DOI: 10.1080/00380768.2013.866522].
Language: English
Date: 2013
Mudflat soil, sewage sludge, perennial rye-grass, biomass, heavy metals

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