[Effects of Biochar Addition on Soil Nitrogen Mineralization and Leaching Characteristics in Riparian Zone of Taihu Lake].

Nitrogen mineralization in riparian soil changes the migration and utilization efficiency of nitrogen, which is closely related to the control of water eutrophication. The differences in soil properties caused by land use alter nitrogen retention and transport capacity. Therefore, the soil of three land use types (woodland, grassland, and cultivated land) in the western riparian zone of Taihu Lake were selected for research on the dynamic changes in nitrogen mineralization amount using an incubation experiment and a leaching characteristics by soil column leaching experiment, and their environmental effects were also studied under different biochar addition conditions (0%, 1%, and 5%).

[Comparison of Available Nitrogen and Phosphorus Characteristics in the Land-Water Transition Zone of Different Watersheds and Their Environmental Significance].

In order to explore the characteristics and environmental significance of available nitrogen and phosphorus in different land-water transition zones, soil and sediment samples from three study areas, including the upstream watershed of Minjiang River (MJU), western watershed of Hongze Lake (HZW), and western watershed of Taihu Lake (THW), were collected and analyzed. The results showed that the contents of total nitrogen and phosphorus in THW were higher than those of other two study areas. The contents of nitrogen and phosphorus in sediments were higher than those in soils of HZW.

[Effects of Biochar Input on Changes of Available Nutrient Elements in Riparian Soils with Different Landuse Types].

Biochar, as a new environmentally friendly material, has been used to improve soil quality and for pollution remediation. Biochar input has a significant impact on available nutrients in the soil. Based on the different land use types (forestland, grassland, cultivated land, and barren land) in the riparian zone of Taihu Lake, the effects of biochar application on the available content of nutrients in different land use types of soil were compared, and the dynamics of nutrient change was also discussed.

Soil microbiome-induced changes in the priming effects of C-labelled substrates from rice residues.

Knowledge gap exists to understand the soil CO emission and microbial group response to substrates of whole plant residues and derived biochar. We used C-labelled substrates (rice straw, roots and biochar) to track influences of their decomposition on soil priming effect (PE) and phospholipid fatty acid (PLFA) composition during one-year incubation. Organic substrates at 1% (w/w) level increased soil pH, available nitrogen (AN) and available phosphorus (AP), especially during the first 45 days of incubation.

Effect of amendments on soil Cd sorption and trophic transfer of Cd and mineral nutrition along the food chain.

Phytotoxicity of cadmium (Cd) and its trophic transfer along a terrestrial food chain have been extensively investigated. However, few studies focused on the role of amendments on the trophic transfer of Cd and related mineral nutrients. In a 60-day pot experiment, soil Cd availability, accumulation of Cd, mineral nutrients (Ca and Si) in lettuce, and subsequent trophic transfer along the lettuce-snail system were investigated with or without 3% (w/w) soil amendment (biochar or micro-hydroxyapatite, μHAP).

[Spatial Distribution of Organic Phosphorus in Sediment and Its Environmental Implication in the Upper Stream of Minjiang River].

In order to explore the effect of land use pattern on phosphorus distribution and the potential release capacity of stream sediment in the upper Minjiang River, this paper presented organic phosphorus forms and their spatial distribution characteristics of sediments in the upper Minjiang River by using the IVANOFF method and discussing the effects of physicochemical properties of sediments on the distribution of organic phosphorus forms. The results show that:①nitrogen and phosphorus contents of sediments in Jianxi and Shaxi catchments are higher than those in the Futunxi catchment, probably related to the large number of farmland runoff and municipal sewage near the Jianxi and Shaxi catchments and the large forest area around the Futunxi catchment;②contents in the sediments from three catchments and TP contents in the sediments from Jianxi and Futunxi catchments showed the order of upper reaches < middle reaches < lower reaches, which may be caused by the mountainous and forested areas in the upper reaches and the intensive human activities in the middle and lower reaches;③nitrogen phosphorus in sediments of the three catchments were mainly non-active organic phosphorus, which indicated that upper reaches of the Minjiang river were generally less affected by external pollution, and the relative proportion of organic phosphorus in the sediments of different catchments was relatively large, while the change in different sections of the same river was relatively small;④physicochemical properties of sediments had a significant impact on the morphology and distribution of organic phosphorus, among which the effects of organic matter, TP, and TN were the most obvious, but the effects on sediments in different river basins were different. Therefore, to protect the water quality of the upper Minjiang River, it is necessary to strengthen the control of the living and agricultural pollution sources near the catchments.

Effects of soil amendments on cadmium transfer along the lettuce-snail food chain: Influence of chemical speciation.

Cadmium (Cd) trophic transfer along the soil-lettuce-snail food chain was investigated using the root bags-based pot experiments. Two amendments (corn straw biochar and micro-hydroxyapatite (μHAP)) were investigated on Cd (0, 2.5, and 5 mg/kg soil) availability in soils, chemical distribution in plant cells and accumulation in snails.

Leaf aging effects on copper and cadmium transfer along the lettuce-snail food chain.

Metal bioavailability at root plasma membrane surfaces and chemical forms within cells putatively controls the trophic transfer processes. Accumulation and distribution of Cu or Cd in lettuce were investigated as a function of lettuce leaf aging through soil-solution culture experiments. Metal contents in snail tissues were examined after fed on young (interior) or old (exterior) age leaves for 15d, respectively.

[Spatial Distributions of Transferable Nitrogen Forms and Influencing Factors in Sediments from Inflow Rivers in Different Lake Basins].

It is necessary to investigate the distribution of nitrogen forms in river sediments to recognize the water environment quality. In this study, ion exchangeable form nitrogen(IEF-N), weak acid extractable form nitrogen (WAEF-N), strong alkali extractable form nitrogen (SAEF-N) and strong oxidation extractable form nitrogen (SOEF-N) in sediments were obtained by means of sequential extraction procedures.We analyzed the spatial variations of nitrogen forms in sediments from Taihu watershed (Dongtiaoxi River and Xitiaoxi River) and Hongzehu watershed (Anhe River and Suihe River), and expounded the influence factors of nitrogen form distribution.

Modeling the interaction and toxicity of Cu-Cd mixture to wheat roots affected by humic acids, in terms of cell membrane surface characteristics.

Responses of wheat (Triticum aestivum L.) seedling roots to the mixtures of copper (Cu), cadmium (Cd) and humic acids (HA) were investigated using the solution culture experiments, focusing on the interaction patterns between multiple metals and their influences on root proton release. A concentration-addition multiplication (CA) model was introduced into the modeling analysis.

[Characteristics and Pollution Source Analysis of Nutrients in Tributary Outlets of Xitiaoxi Watershed].

The input of tributary is the important source of nutrients to the main stream, and it is the key area for water pollution control of watershed. In order to explore the sources of nutrient and seek the effective measures to control the river pollution, the spatial and temporal variations of aquatic parameters and the output of nutrient flux in the tributary outlets of Xitiaoxi watershed were analyzed. The quantitative analysis concerning the contribution of pollution sources from 10 typical tributaries was carried out, using the PMF analytical model.

[Characteristics of heavy metals in sediments from different sources and their ecological risks in the lower reaches of the Yangtze River].

Characteristics of heavy metals in sediments from different sources are significant varied,which impact on the degree of damage for aquatic system. Samples from municipal, mining, industrial and port sources in the lower reaches of the Yangtze River were analyzed for major elements and Cu, Zn, Pb, Cd, Cr by ICP-AES and AAS. The results showed that the concentrations were moderately and relatively uniform for heavy metals in the municipal source, Cu, Pb were dominated for the mine source.