Evaluation of Sewage Sludge Effects on Soil Properties, Plant Growth, Mineral Nutrition State, and Heavy Metal Distribution in European Larch Seedlings (Larix decidua)

Soil heavy metals along roadsides pose a great threat to ecosystems while their spatial variations and influencing factors still remain unclear in some regions, especially in tropical areas with complex landscape characteristics. Our study was carried out to determine how the land use, vegetation characteristics, topographical factors and distance to the road affect the soil heavy metal distribution. Taking Jinghong county in Yunnan Province, Southwest China as a case, soil samples were collected at different distances off roads and canonical correspondence analysis (CCA) methods were used to determine the relative importance of different factors. Our results showed that heavy metal sources were obtained mainly from the road, based on the principle component analysis (PCA) identification. There were no obvious trends of soil quality index (SQI) with distance to the road in natural soils, while SQI nutrients and SQI metals in farmlands had a decreasing and increasing trend, respectively, which could both be expressed by logarithm models. However, soil properties showed little differences for road levels while they showed significant differences under land use types. The CCA further showed that heavy metal variations in natural soils were jointly affected by distance, plant coverage, relative elevation and soil properties in decreasing order.

Download Full-text

Investigations on the Heavy Metal Distribution in the Turbidity Zone of the River Elbe Estuary (F.R.G.)

Water Science & Technology ◽

10.2166/wst.1986.0253 ◽

1986 ◽

Vol 18 (4-5) ◽

pp. 345-345

Author(s):

F. Schroeder ◽

R.-D. Wilken

Keyword(s):

Heavy Metal ◽

Metal Distribution ◽

Elbe Estuary ◽

Heavy Metal Distribution ◽

River Elbe

Download Full-text

Sewage sludge application enhances soil properties and rice growth in a salt-affected mudflat soil

Scientific Reports ◽

10.1038/s41598-020-80358-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yuhua Shan ◽

Min Lv ◽

Wengang Zuo ◽

Zehui Tang ◽

Cheng Ding ◽

...

Keyword(s):

Sewage Sludge ◽

Organic Carbon ◽

Plant Growth ◽

Root Growth ◽

Soil Fertility ◽

Soil Properties ◽

Soluble Sugar ◽

Soil Reclamation ◽

Rice Growth ◽

Promote Plant Growth

AbstractThe most important measures for salt-affected mudflat soil reclamation are to reduce salinity and to increase soil organic carbon (OC) content and thus soil fertility. Salinity reduction is often accomplished through costly freshwater irrigation by special engineering measures. Whether fertility enhancement only through one-off application of a great amount of OC can improve soil properties and promote plant growth in salt-affected mudflat soil remains unclear. Therefore, the objective of our indoor pot experiment was to study the effects of OC amendment at 0, 0.5%, 1.0%, 1.5%, and 2.5%, calculated from carbon content, by one-off application of sewage sludge on soil properties, rice yield, and root growth in salt-affected mudflat soil under waterlogged conditions. The results showed that the application of sewage sludge promoted soil fertility by reducing soil pH and increasing content of OC, nitrogen and phosphorus in salt-affected mudflat soil, while soil electric conductivity (EC) increased with increasing sewage sludge (SS) application rates under waterlogged conditions. In this study, the rice growth was not inhibited by the highest EC of 4.43 dS m−1 even at high doses of SS application. The SS application increased yield of rice, promoted root growth, enhanced root activity and root flux activity, and increased the soluble sugar and amino acid content in the bleeding sap of rice plants at the tillering, jointing, and maturity stages. In conclusion, fertility enhancement through organic carbon amendment can “offset” the adverse effects of increased salinity and promote plant growth in salt-affected mudflat soil under waterlogged conditions.

Download Full-text