Aquaculture sediments amended with biochar improved soil health and plant growth in a degraded soil.

Sustainable and safe management of aquaculture sediments is of great concern. Biochar (BC) and fishpond sediments (FPS) are rich in organic carbon and nutrients and thus can be used as soil amendments; however, it is not fully explored how the biochar amended fishpond sediments can affect soil properties/fertility and modulate plant physiological and biochemical changes, particularly under contamination stress. Therefore, a comprehensive investigation was carried out to explore the effects of FPS and BC-treated FPS (BFPS) on soil and on spinach (Spinacia oleracea L.) grown in chromium (Cr) contaminated soils. Addition of FPS and BFPS to soil caused an increase in nutrients content and reduced Cr levels in soil, which consequently resulted in a significant increase in plant biomass, chlorophyll pigments, and photosynthesis, over the control treatment. The most beneficial effect was observed with the BFPS applied at 35 %, which further increased the antioxidant enzymes (by 2.75-fold, at minimum), soluble sugars by 24.9 %, and upregulated the gene expression activities. However, the same treatment significantly decreased proline content by 74.9 %, Malondialdehyde by 65.6 %, H2O2 by 65.1 %, and Cr concentration in spinach root and shoot tissues. Moreover, the average daily intake analysis showed that BFPS (at 35 %) could effectively reduce human health risks associated with Cr consumption of leafy vegetables. In conclusion, these findings are necessary to provide guidelines for the reutilization of aquaculture sediments as an organic fertilizer and a soil amendment for polluted soils. However, more future field studies are necessary to provide guidelines and codes on aquaculture sediments reutilization as organic fertilizer and soil amendment for polluted soils, aiming for a more sustainable food system in China and globally, with extended benefits to the ecosystem and human.

Hazardous toxic metal(loid)s in top- and deep-soils during the transformation of aquaculture ponds restored to farmland.

The pollution risks due to the soil migration of toxic metal(loid)s (TMs) are a greatly hazard to ecological environment as well as animal and human health. Previous studies have primarily focused on surface contamination while deep soil layers often contain dangerous levels of TMs. We used restored wheat and rice farmlands from aquaculture ponds as a case study to examine the ecological risk and distribution of TMs in soil profiles. The elements Cu, Zn, Cr, Cd, Hg and As were markedly enriched in the 60-180 cm soil layers of restored farmland, and their concentrations decreased in the several depths as follows: 120-180 cm > 60-120 cm > 0-60 cm. Concentrations of TMs were 9.5-128 % greater in the restored farmlands relative to farmlands not exposed to aquaculture practices. Cadmium and mercury were the most serious contaminants and increased the overall ecological risk. The subsoil of wheat farming system had the highest pollution risk versus the restored rice farmland at 60-120 cm due to elevated levels of Cu, Zn and Pb. Toxic metal(loid)s might be derived from natural sources in deep soil of conventional farmland whereas aquaculture practices were found to constitute the major contribution in the subsoil of restored farmland. Our results indicated that the TMs that were buried in deep soil layers migrated upward and were a significant pollution risk. Urgent actions should be taken to identify and alleviate the contamination sources of these deep soils in addition to the conventional leaching and migration processes of surface contaminants.

Sustainable Strategies for the Agricultural Development of Shaanxi Province Based on the Risk Assessment of Heavy Metal Pollution.

Heavy metal elements in farmland soil can be absorbed by crops and endanger food security. To assess the risk of heavy metal elements in farmland soil to crops in Shaanxi Province, we collected 693 soil samples and analyzed the concentrations of nine heavy metals (As, Hg, Pb, Cd, Cr, Mn, Cu, Zn, and Ni). According to the National Standard (GB 15619-2018) of the People's Republic of China, the proportions of soil sample points in which the concentration of heavy metals was higher than the risk screening value were 2.02% (Cd), 0.29% (Cr), 0.29% (Zn), 2.31% (Cu), 1.15% (Ni), and 0.14% (Pb). The proportions of areas in which the concentration of heavy metal was higher than the background value were as follows, from largest to smallest: Zn (53.20%) > Mn (49.86%) > Cd (29.51%) > Hg (26.77%) > As (26.58%) > Ni (14.95%) > Cu (13.90%) > Pb (6.49%) > Cr (1.40%). The assessment of the risk of heavy metal exposure (geo-accumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (RI)) determined that Hg was the most concerning heavy metal in the farmland soil of Shaanxi Province. Moreover, 11.56% of these areas had Hg contamination, and they were mainly distributed in the western Guanzhong region. The farmland soil in the Guanzhong region was the most contaminated, followed by the southern Shaanxi region and then the northern Shaanxi region. The main sources of heavy metal contamination causing large-scale farmland soil pollution are agricultural production activities, transportation, and air pollution caused by coal combustion in Shaanxi Province. Therefore, sustainable strategies for the prevention and control of heavy metal pollution and agricultural development must be applied in different regions. Heavy metal pollution should be managed, and relevant policies should be created and enforced, such as the standardization of the use of qualified pesticides and fertilizers, improved treatment of livestock and poultry manure, development of the clean energy industry structure, and promotion of renewable energy vehicles. In terms of the high-quality development of agriculture, developing modern and local agriculture in different regions should be based on local geographical, climatic, and economic conditions.

Fluorescence and molecular signatures of dissolved organic matter to monitor and assess its multiple sources from a polluted river in the farming-pastoral ecotone of northern China.

The sources and composition of dissolved organic matter (DOM) in rivers are critical to water quality and aquatic ecosystems. Studies on detailed composition of organic matter in rivers in the farming-pastoral ecotone are relatively limited in the research community. To better understand the characteristics and dynamics of DOM, Yang River in North China was selected as the study area because of its profound influences on the farming-pastoral ecotone nearby. A combination of fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) techniques revealed that the DOM composition of Yang River is driven by land use. DOM in Yang River is predominantly imported from allochthonous inputs, together with agricultural runoff, pastureland, and urban sewage, causing a comprehensive impact on DOM. In detail, DOM associated with cropland inputs was dominated by lignin-like species, with higher nitrogen content. In comparison, DOM related to grassland is more diverse and susceptible to degradation. An increase in urban areas led to an increase in sulfur-containing compounds, while their oxygen, nitrogen, and aromaticity contents were significantly lower than those in cropland. Interestingly, urban-influenced lignin-like compounds may be associated with the effluents from the pulp and paper mill. Additionally, synthetic surfactants from the lower section of the river were also structurally identified by tandem mass spectrometry. Overall, this study could provide valuable insights into the DOM sources and their transformation dynamics at a molecular level, which could be an indicator for riverine water quality management and be applied to other farming-pastoral ecotones straightforward.

Re-utilization of Chinese medicinal herbal residues improved soil fertility and maintained maize yield under chemical fertilizer reduction.

Excessive utilization of chemical fertilizers (CF) is not a sustainable agricultural development strategy due to adverse effects on soil health. In contrast, a combination of organic and mineral fertilizers has a positive effect on both soil health and productivity. Chinese medicinal herbal residues (CMHR) is the plant material wastes remaining after drug extraction but has not been extensively used as fertilizer. We evaluated application of CMHR to maize fields over 3 consecutive growing seasons in the presence and absence of standard CF to assess improvements in soil fertility, maize yields and sustainable development. CMHR fertilization increased soil organic matter and total N and K when mixed with chemical fertilizer at 50 and 75% the standard application rate. Soil organic matter increased by 27.0-51.4% and available -N, -P and -K levels and grain yields as well as N and P use efficiency in the presence of CMHR mixes were similar to levels obtained with chemical fertilizer only. These increases in production were due to increased leaf areas, photosynthetic rates, grain number and 1000-grain weights. The addition of CMHR to fields posed a slightly risk of toxic-metal pollution. Overall, we found that (1) CMHR can be used as an effective organic fertilizer and replace up to 50% of the amount of chemical fertilizer normally applied to fields without hampering maize grain yields and (2) CMHR application to agricultural fields is an effective recycling strategy and nutrient management practice to improve soil fertility under CF usage reduction.

Microbial characteristics response to the soil quality of newly created farmland on the Loess Plateau.

Microbiome plays an important role in evaluating soil quality for sustainable agriculture. However, the suitability of biological indicators in reclaimed farmland is less understood. Using high-throughput sequencing, we evaluated the soil microbial community of the newly created farmland (NF) after reclamation with two local high-yield farmlands (slope farmland (SF), check-dam farmland (CF)) on the Loess Plateau. Soil enzyme activities and the amount of culturable microorganism were also quantified to assess the soil quality. Results showed that the microbial diversity, cultural microorganism abundance, and soil enzyme activities indicated poor soil quality in NF. The dominant bacterial phyla were Proteobacteria, Bacteroidetes, Acidobacteria, and Cyanobacteria. The abundance of Acidobacteria was significantly lower in NF (13.31%) than in SF (27.25%) and CF (27.91%). Soil enzyme activities had a significant correlation with the abundance of culturable microorganism, Proteobacteria and Bacteroidetes, soil organic matter, total nitrogen, cation exchange capacity, and pH, suggesting that soil microbes have driven the formation of nutrition and further mediated crop growth. Therefore, the application of bacterial fertilizers could be a potential way to improve the soil quality of reclaimed farmland for crop growth.

Assessment of heavy metal(loid)s contamination risk and grain nutritional quality in organic waste-amended soil.

Studies that evaluate the human health risk of heavy metal(loid)s pollution have not been widely performed for organic waste-amended soils on the Loess Plateau of China. With this respect, we conducted a 3-year field trial to estimate the heavy metal(loid)s contamination of soil and maize, the resultant nutritional quality of maize grains and the health risk under treatments of conventional fertilizer (CF), traditional Chinese medicine residue (TCMR) and sheep manure (SM). We found that protein, amino acids and lysine in maize grains were increased by 12.3, 11.3 and 5.88 % under TCMR treatments relative to SM application, respectively. Meanwhile, this treatment reduced the levels of Cr, Pb, Cd, As and Hg in soil and maize grains. All fertilization regimens resulted in greater health risks for children, with HI values ranging from 1.06 to 1.52 and CR levels for Cr and As being ï¹¥1.0 × 10-4, especially higher in SM treatments. This presented the beneficial effect of TCMR than SM. The further investigated of toxic metal(loid)s level in SM and its application risks, based on meta-analysis and Monte Carlo simulation, indicated Cd, Hg and Pb were the most cautionary heavy metal(loid)s and contamination risk were greater on the southwest regions of China.

Ultrasensitive dual-color rapid lateral flow immunoassay via gold nanoparticles with two different morphologies for the serodiagnosis of human brucellosis.

Lateral flow immunoassays (LFIAs) are popular because they are rapid, convenient, stable, low cost, and easy to read. However, conventional LFIAs based on gold nanoparticles lack sensitivity, which hinders their widespread use. Here, we prepared durian-like gold nanoparticles (GNDs) and labeled them with staphylococcal protein A to detect brucella antibody. Then, the analytical performances of GNDs and gold nanospheres (GNSs) with the same diameter were compared. It was found that the sensitivity of GNDs was five to ten times higher than that of GNSs. The nonspherical morphologies of the nanoparticles greatly increased the sensitivity of the LFIA. On the basis of GNDs and GNSs, we developed an ultrasensitive dual-color brucellosis LFIA. GNSs labeled with streptavidin were used to demonstrate the control line. This dual-color LFIA had a diagnostic sensitivity and specificity of 100%. Human standard Brucella-positive serum (containing brucella antibody at 4000 IU/mL) could be detected in this system even for a dilution factor of 10-5. The detection limit was 0.04 IU/mL. This is two orders of magnitude better than conventional LFIA strips (detection limit 4 IU/mL). This dual-color LFIA contains all components of a conventional LFIA with no additional processing steps or reagents. It can detect antibodies in serum, plasma, and even whole blood without sample pretreatment or blood filtration pads. Both types of nanoparticles were synthesized in a simple and low-cost manner. This suggests that it will have utility for the early diagnosis of brucellosis and other diseases. Graphical abstract.

Effects of traditional Chinese medicine residue on plant growth and soil properties: a case study with maize (Zea mays L.).

Traditional Chinese medicine residue (TCMR) is the solid substances remaining after the extraction of pharmaceutical ingredients from medicinal plant materials, which include abundant soil nutrients. However, TCMR is nearly lost as domestic garbage, which not only occupies a large amount of land but also leads to the waste of resource, as well as causing the eco-environment potential pollution. Therefore, we implemented this study to assess whether TCMR could be used as an organic fertilizer in agricultural practices for realizing waste resource utilization, improving soil fertility, and enhancing plant growth. The results showed that (1) application of TCMR could improve soil fertility, particularly in enhancing the soil contents of SOM, TN, NaOH-N, NaHCO3-P, and HNO3-K; (2) the higher application ratios of TCMR (0.8-1.0%) that increased the soil EC values would cause the risk of soil secondary salinization; (3) the lower application ratios of TCMR (0.2-0.6%) has a better positive effect on improved the maize seedlings' physiological parameters and photosynthetic performance than the higher application ratios; (4) although application of TCMR lead to the heavy metal (Cr, Pb, Cd, As, and Hg) content increased in soil, there was no ecology risk under below 0.8% application ratio, compared with the China soil risk control standards, geo-accumulation index (Igeo), and pollution load index (PLI). Thus, TCMR could potentially be used as an organic fertilizer in agricultural practices. This approach is an effective strategy not only for achieving TCMR disposal but also for realizing waste resource utilization, as well as for improving soil fertility and plant growth.

Biochar can improve the soil quality of new creation farmland on the Loess Plateau.

The Loess Plateau is the most severely degraded soil area worldwide and represents one of the lowest areas of soil productivity. To solve the conundrum between increasing populations and decreasing agricultural acreage, enhancing the quantity of cultivated land, gully land consolidation projects has been implemented. However, the new creation farmland soil is not enough to satisfy the demand of agricultural production. An incubation experiment was conducted to determine the effects of biochar on the new creation farmland soil. Five levels of amendments (0, 1%, 2%, 5%, and 10% (wt%) biochar soil) were used, and the soil columns remained in the laboratory for approximately 2 months. The results show that biochar proportion was a more important factor than incubation time across all soils tested. The soil moisture content and particle size clearly increased as the amendment level increased; however, the soil pH decreased gradually with incubation time and tended to slow soil salinization. These findings will have to be verified under field conditions.