Risk assessment of China's Eastern Route of the South-to-north Water Diversion Project from the perspective of Phthalate Esters occurrence in the impounded lakes.

Phthalate esters (PAEs) are widely utilized and can accumulate in lacustrine ecosystems, posing significant ecological and human health hazards. Most studies on PAEs focus on individual lakes, lacking a comprehensive and systematic perspective. In response, we have focused our investigation on characteristic lakes situated along the Eastern Route of the South-to-north Water Diversion Project (SNWDP-ER) in China. We have detected 16 PAE compounds in the impounded lakes of the SNWDP-ER by collecting surface water samples using solid-phase extraction followed by gas chromatography analysis. The concentration of PAEs were found to between 0.80 to 12.92 µg L-1. Among them, Bis (2-ethylhexyl) phthalate (DEHP) was the most prevalent, with mean concentration of 1.56 ±â€¯0.62 µg L-1 (48.44%), followed by Diisobutyl phthalate (DIBP), 0.64 ±â€¯1.40 µg L-1 (19.87%). Spatial distribution showed an increasing trend in the direction of water flow. Retention of DEHP and DIBP has led to increased environmental risks. DEHP, Dimethyl phthalate (DMP) etc. determined by agriculture and human activities. Additionally, Dibutyl phthalate (DBP) and DIBP mainly related to the use of agricultural products. To mitigate the PAEs risk, focusing on integrated management of the lakes, along with the implementation of stringent regulations to control the use of plasticizes in products.

Effects of Common Biochar and Acid-Modified Biochar on Growth and Quality of Spinach in Coastal Saline Soils.

The rational development and efficient utilization of saline soils can alleviate the problem of insufficient arable land faced by agricultural production in China. A prominent problem is improving soil salt and water conditions for promoting land resources' productivity in coastal areas. Biochar is widely used for soil improvement, as it has remarkable properties. A pot experiment was conducted to study the effects of two kinds of biochar (common biochar and acid-modified biochar) with three addition rates (2%, 4%, and 8%) on the growth, yield, photosynthetic characteristics, and quality of spinach. The results revealed that 2% and 4% common biochar increased the plant height, stem diameter, and leaf area index, effectively improving the yield of spinach and water productivity, while 8% common biochar was detrimental to the growth of spinach to some extent. Acid-modified biochar significantly benefited the growth and increased the water productivity of spinach, ensuring high yields, while also improved quality. Similarly, acid-modified biochar was less effective at high additions than at low-to-medium additions. The integrated biological response version 2 (IBRV2) values under acid-modified biochar treatments were all significantly higher than those under common biochar, but there is no significant difference among three treatments in the same biochar group, which suggested a pronounced amelioration in spinach growth within saline-alkali soil upon the incorporation of acid-modified biochar. Overall, applying acid-modified biochar at the rate of 4% exhibited enormous potential for increasing the yield and quality of spinach in saline soils.

Effects of different colors of film mulch on soil temperature and rice growth in a non-flooded condition.

BACKGROUND: Rice cultivation under film mulching with no flooding is widely used as an effective water-saving technology. Different colors of film mulch have different effects on the soil hydrothermal environment and crop growth because of their different optical properties. However, the effects of different colors of film mulch on soil temperature and rice physiological growth are not clearly understood. RESULTS: Field experiments were conducted in 2019 and 2020 to investigate the effects of different color mulches on soil temperature and rice growth in a non-flooded condition. Transparent film (TM), black film (BM), two-color film (BWM, silver on the front and black on the back), and no film (NM) in a non-flooded condition were designed. Soil temperature variation at different soil depths of 0-0.25 m and rice plant height, stem thickness, dry matter, yield and quality were monitored. The results showed that compared to no mulching, the mulching treatment effectively increased the average soil temperature during the whole rice growth stage with the soil temperature ranked TM > BM > BWM. Compared with NM, the BM and BWM treatments increased rice yield by 12.1-17.7% and 6.4-14.4% in 2019 and 2020, respectively. The BWM had 18.2% and 6.8% greater gel consistency than NM in 2019 and 2020, respectively. CONCLUSION: Transparent film should be applied with care because of the high soil temperature stress. Black film and two-color film (silver on the front and black on the back) could be better option for rice yield, increasing and quality improving in a non-flooded condition. © 2023 Society of Chemical Industry.

Combined remediation effects of biochar and organic fertilizer on immobilization and dissipation of neonicotinoids in soils.

Neonicotinoid (NEO) pesticides have become a potential risk to ecological safety and human health after application. The combined use of biochar and organic fertilizer (OF) is a promising approach to reduce pesticide adverse effects and improve soil fertility in agricultural soils. However, the combined remediation effects of biochar and OF on immobilization and dissipation of NEOs in soils have not previously been systematically investigated. In this study, biochars derived from peanut shell prepared at low/high pyrolysis temperatures (PS400 and PS900) were combined with composted chicken manure (CCM) as an example for OF to remediate contaminated soils toward six typical NEOs, nitenpyram (NIT), thiamethoxam (THIA), clothianidin (CLO), imidacloprid (IMI), acetamiprid (ACE), thiacloprid (THI). Results shown that both biochars and CCM were effective in improving soil sorption capacity and immobilization efficiency. The Freundlich affinity parameters (Kf) of NEOs in soils increased 7.2-12.0 times after the combined remediation of biochar and CCM, and the Kf of six NEOs had negative correlation with their lipophilicity (p < 0.05), which followed by THI > ACE ≈ IMI > CLO > THIA > NIT. Meanwhile, NEOs-abiotic degradation was accelerated by biochar, CCM and their combined addition by adjusting soil pH and stimulating hydrolysis action. Biotic degradation was dominant in NEOs dissipation processes in amended soils, and the contribution ratios of biotic degradation (CRbio) were in the range of 25.4-99.0%. The combined use of biochar and CCM selectively stimulated the relative abundance of NEOs-degraders, which simplified abiotic degradation of -NO2-containing NEOs (viz., NIT, THIA, CLO, and IMI), but inhibited -C≡N-containing NEOs (viz., ACE and THI). The combined remediation provided a strategy for immobilizing NEOs and facilitating dissipation of -NO2-containing NEOs in soils. The results in this study provide valuable information for policymakers and decision-makers to choose appropriate soil remediation approaches with respect to the NEO types.

Quantifying the interaction of water and radiation use efficiency under plastic film mulch in winter wheat.

Local natural resources, (e.g., precipitation, solar radiation) are important for developing environmentally and scientifically sound management practices in dryland agroecosystem. Maximizing water use efficiency (WUE) in dryland farming systems remains a challenge. The objectives of this study were to assessing the robustness of radiation use efficiency (RUE) during different periods and investigate the interaction between RUE and WUE from water loss pattern and canopy development during wheat growth under different agricultural practices (non-mulched control, CK; transparent film mulching, TF; and black film mulching, BF) from 2013 to 2016 on the Loess Plateau, Northwest China. Results showed that RUE was mainly improved during post-anthesis under PM treatments. PM treatments contributed to elevated canopy photosynthesis and a delayed RUE peak during the reproductive period. Due to the increased spike number and ratio of plant transpiration to soil evaporation, TF and BF treatments had relatively stable photosynthetic activity relative to the CK treatment even those during dry periods. Initially, no relationship was found between WUE and RUE under the CK treatment. On the other hand, RUE and WUE were positively related in TF and BF treatments following a power function. RUE values increased with WUE rapidly to stabilize at a plateau value of 5.5 g MJ-1 under TF and BF treatments, and thus, the wheat WUE had a higher improvement potential than RUE as it did not have an apparent plateau value. PM treatments enhanced the wheat production by taking full advantage of local solar radiation and precipitation (improving RUE and WUE). This higher use efficiency of resources produced more photoassimilates for wheat than that under the CK management, increased source size (LAI) and sink size (spike number) during wheat growth seasons, and thus increased the final grain yield.

Deciphering the mechanism of medium size anammox granular sludge driving better nitrogen removal performance.

In this study, an integrated investigation to the microbial activities, extracellular polymeric substance (EPS), microbial community and function of anammox granular sludge (AnGS) was performed.Results showed that AnGS at 0.5-1.0 mm had the highest average specific anammox activity (SAA) of 345.9 mg NH4+-N·gVSS-1·d-1, but AnGS at 1.0-1.5 mm with higher SAA might lead to better nitrogen removal efficiency. The content of slime EPS and SAA achieved positively correlation with R2 of 98.11%, while protein/polysaccharide ratio of slime EPS and sludge volume index achieved negatively correlation with R2 of 99.13%. Cadidatus Broccadia and Denitratisoma were positive correlations and most abundant in AnGS 0.5-1.0 mm of 20% and AnGS 1.0-1.5 mm of 37%, respectively. AnGS at 0.5-1.0 mm exhibited higher energy metabolism which mostly contributed to produce protein. The study provides new insights into the mechanisms of AnGS about 1 mm playing more important role in nitrogen removal performance.

Effects of residue removal and tillage on greenhouse gas emissions in continuous corn systems as simulated with RZWQM2.

Agricultural production is a major source of carbon dioxide (CO2) and nitrous oxide (N2O) globally. The effects of conservation practices on soil CO2 and N2O emissions remain a high degree of uncertainty. In this study, soil CO2 and N2O emissions under different residue and tillage practices in an irrigated, continuous corn system, were investigated using the Root Zone Water Quality Model (RZWQM2). Combinations of no/high stover removal (NR and HR, respectively) and no-till/conventional tillage (NT and CT, respectively) field experiments were tested over the four crop-years (Apr. 2011-Apr. 2015). The model was calibrated using the NRCT, and validated with other treatments. The simulation results showed that soil volumetric water content (VWC) in the NR treatments (i.e., NRCT and NRNT) was 1.3%-1.9% higher than that in the HR treatments (i.e., HRCT and HRNT) averaged across the four years. A higher amount of CO2 and N2O emissions were simulated in the NRCT across the four years (annual average: 7034 kg C/ha/yr for CO2 and 3.8 kg N/ha/yr for N2O), and lower emissions were in the HRNT (annual average: 6329 kg C/ha/yr and 3.7 kg N/ha/yr for N2O). A long-term simulation (2001-2015) suggested that the CO2 and N2O emissions were closely correlated with the stover removal degree (SRD), tillage, VWC, soil temperature (ST), years in management (Y), and fertilizer application. Stover and tillage practices had cumulative effects on CO2 emissions. The simulated annual CO2 emissions in 1st year from NRCT, NRNT, and HRCT were 7.8%, 0.0%, and 7.7% higher than that from HRNT, respectively; then the emissions in 15th year were 63.6%, 47.7%, and 29.1% higher, respectively. Meanwhile, there were no cumulative effects on N2O emissions. The results also demonstrated that the RZWQM2 is a promising tool for evaluating the long-term effects of CO2 and N2O emissions on different conservation practices.

Quantifying long-term responses of crop yield and nitrate leaching in an intensive farmland using agro-eco-environmental model.

Quantitatively ascertaining and analyzing long-term responses of crop yield and nitrate leaching on varying irrigation and fertilization treatments are focal points for guaranteeing crop yield and reducing nitrogen loss. The calibrated agricultural-hydrological RZWQM2 model was used to explore the long-term (2003-2013) transport processes of water and nitrogen and the nitrate leaching amount into groundwater in summer maize and winter wheat rotation field in typical intensive plant area in the North China Plain, Daxing district of Beijing. Simulation results showed that application rates of irrigation and nitrogen fertilizer have couple effects on crop yields and nitrogen leaching of root zone. When both the irrigation and fertilizer for summer maize and winter wheat were 400mm and 400kgNha-1, respectively, nitrate leaching into groundwater accounted for 47.9% of application amount of nitrogen fertilizer. When application amount of irrigation is 200mm and fertilization is 200kgNha-1, NUPE (nitrogen uptake efficiency), NUE (nitrogen use efficiency), NPFP (nitrogen partial factor productivity), and Wpi (irrigation water productive efficiency) were in general higher than that under other irrigation and fertilization condition (irrigation from 104-400mm, fertilizer 104-400kgNha-1). Irrigation bigger than 200mm could shorten the response time of nitrate leaching in deeper soil layer in different irrigation treatment.

Neural networks to simulate regional ground water levels affected by human activities.

In arid regions, human activities like agriculture and industry often require large ground water extractions. Under these circumstances, appropriate ground water management policies are essential for preventing aquifer overdraft, and thereby protecting critical ecologic and economic objectives. Identification of such policies requires accurate simulation capability of the ground water system in response to hydrological, meteorological, and human factors. In this research, artificial neural networks (ANNs) were developed and applied to investigate the effects of these factors on ground water levels in the Minqin oasis, located in the lower reach of Shiyang River Basin, in Northwest China. Using data spanning 1980 through 1997, two ANNs were developed to model and simulate dynamic ground water levels for the two subregions of Xinhe and Xiqu. The ANN models achieved high predictive accuracy, validating to 0.37 m or less mean absolute error. Sensitivity analyses were conducted with the models demonstrating that agricultural ground water extraction for irrigation is the predominant factor responsible for declining ground water levels exacerbated by a reduction in regional surface water inflows. ANN simulations indicate that it is necessary to reduce the size of the irrigation area to mitigate ground water level declines in the oasis. Unlike previous research, this study demonstrates that ANN modeling can capture important temporally and spatially distributed human factors like agricultural practices and water extraction patterns on a regional basin (or subbasin) scale, providing both high-accuracy prediction capability and enhanced understanding of the critical factors influencing regional ground water conditions.

[Effects of non-sufficient irrigation with saline water on soil water-salt distribution and spring corn yield].

A field experiment was conducted to study the effects of sufficient and non-sufficient irrigation with saline water on the soil water-salt distribution and spring corn yield in the middle reach of Shiyanghe River Basin. The results showed that under both sufficient and non-sufficient irrigation, the peak value of soil water content all appeared during irrigation period, and the variation range of the water content was higher under sufficient than under non-sufficient irrigation. Soil salinity was positively correlated with the salinity of irrigation water. At the same salinity of irrigation water, the soil salinity under non-sufficient irrigation was lower than that under sufficient irrigation. Under non-sufficient irrigation, the soil layer with salt accumulation was moved up, but the water and salt contents in 80-100 cm soil layer were less affected by the amount and salinity of irrigation water. Comparing with that under fresh water irrigation, the spring corn yield under saline water irrigation was decreased by 15%-22%. Under non-sufficient irrigation with 9 g x L(-1), 6 g x L(-1), and 3 g x L(-1) of saline water, the average salt content in 1 m soil layer after harvest was decreased by 8.1%, 12.4%, and 18.4%, and the corn yield was only decreased by 3.4%, 6.8%, and 3.0%, respectively, compared with those under sufficient irrigation.