Heavy metal pollution impacts on soil microorganisms are of growing concern. This study employed high-throughput sequencing and qPCR to investigate rhizosphere microbial communities and functional genes responses in ryegrass (Lolium perenne L.) under cadmium (Cd) stress. Results showed dose-dependent shifts in microbial diversity, metabolic pathways and functional gene abundance. The relative abundances of bacterial classes Alphaproteobacteria and Bacteroidia and genera Cellvibrio and Algoriphagus increased with Cd levels, suggesting roles in Cd adaptation. The classes Actinobacteria, Saccharimonadia, and Acidimicrobiia and the genera Rheinheimera, Pseudomonas, and Sphingomonas decreased. The fungal genera Acremonium, unclassified Hypocreales, Cladosporium and Paramyrothecium increased under high Cd, while Albifimbria, Fusarium, and Ramichloridium decreased. Differential adaptive strategies to Cd toxicity were observed between bacterial and fungal phyla. Redundancy analysis identified pH, EC, TN, and Cd as key determinants of microbial variation. FAPROTAX prediction revealed significant changes in dominant functional groups involved in nutrient cycling, and FunGuild analysis indicated increased saprophytic fungi with elevating Cd levels, potentially enhancing detoxification. Functional genes related to nitrogen and carbon cycling also varied with Cd gradients. This study systematically elucidated the response of rhizosphere soil microbial communities and functional gene abundance to Cd stress, providing mechanistic insights for developing ryegrass tolerance strategies.

While previous studies have suggested that biochar, nitrification inhibitors, and urease inhibitors may reduce soil greenhouse gas emissions, their effectiveness in soils irrigated with alternative water resources remains unclear. To compensate for this, reclaimed water and livestock wastewater were utilized as alternative water resources alongside groundwater control. Nitrapyrin and N-(n-butyl) thiophosphoric triamide and biochar were applied to the soil either individually or in combination, and a no-substance treatment (NS) was included for comparison. The results revealed that reclaimed water and livestock wastewater irrigation exacerbated the global warming potential. Compared to the NS, all exogenous substance treatments suppressed nitrous oxide (N2O) emissions while increasing carbon dioxide (CO2) emissions, and affecting methane (CH4) emissions varied across treatments irrespective of the water types. Interestingly, the additional biochar reduced the inhibitory effect of the inhibitors on the greenhouse effect. Using nitrification inhibitors reduced the global warming potential by 48.3% and 50.1% under reclaimed water and livestock wastewater irrigation, respectively. However, when nitrification inhibitors were applied in combination with biochar, the global warming potential was increased by 52.1–83.4% compared to nitrification inhibitors alone, and a similar trend was also observed in the scenario of urease inhibitors, with increases ranging from 8.8 to 35.1%. Therefore, the combined application of biochar and inhibitors should be approached cautiously, considering the potential for increased greenhouse gas emissions.

Reclaimed water and sewage sludge as renewable resources are urged to be used in agriculture, but their reuse poses potential chemical and microbiological risks. As a waste biomass resource, sludge combined with reclaimed water irrigation is a major way to develop and utilize renewable resources and control environmental pollution. However, whether reclaimed water irrigation and sludge application have adverse effects on the agricultural environment and human health remains a controversial point of discussion. A greenhouse pot experiment was conducted to investigate the effects of reclaimed water and sewage sludge on rhizosphere soil and root endophytic bacterial communities, the abundance of selected genes, and to evaluate the soil quality of sludge application. The results of this study demonstrated that the application of sewage sludge could result in the accumulation of nutrients in soil. The rhizosphere soil and root endophytic bacteria possessed common dominant groups at phylum level, including Proteobacteria, Bacteroidota, Actinobacteriota and Chloroflexi. Reclaimed water irrigation had less effect on rhizosphere soil and root endophytic bacterial communities than sludge application. Pseudomonas showed a decrease in relative abundance in both rhizosphere soil and root endophytes following sludge application, whereas beneficial bacteria like Bacillus, Stenotrophobacter, Cellvibrio and Altererythrobacter experienced an increase. Redundancy analysis (RDA) showed that the diversity and composition of bacterial communities in rhizosphere soil among treatment groups were closely related to soil organic matter, total nitrogen and total phosphate contents. The functional prediction highlighted the participation of functional groups in nitrogen and carbon cycling as well as degradation processes at varying sludge application rates. The abundance of selected genes was more affected by sludge application. A considerable amount of sludge application to the soil resulted in a significant increase in the abundance of pathogens and antibiotic resistance genes, as well as functional genes, compared to unamended soil with sludge treatment. Direct or excessive application of sludge might aggravate the dissemination and accumulation of deleterious genes in soil-crop systems irrigated with reclaimed water. Overall, our study results may provide valuable information on how sludge influences the microbial community characteristics and abundance of specific genes, guiding the assessment of biological quality and the appropriate use of sludge in agriculture irrigated with reclaimed water.

The application of nitrification inhibitors (nitrapyrin) and urease inhibitors (N-(N-butyl) thiophosphoric triamide) under conventional water resources has been considered as an effective means to improve nitrogen utilization efficiency and mitigate soil greenhouse gas emissions. However, it is not known whether the inhibitors still have an inhibitory effect under unconventional water resources (reclaimed water and livestock wastewater) irrigation and whether their use in combination with biochar improves the mitigation effect. Therefore, unconventional water resources were used for irrigation, with groundwater (GW) control. Nitrapyrin and N-(N-butyl) thiophosphoric triamide were used alone or in combination with biochar in a pot experiment, and CO2, N2O, and CH4 emissions were measured. The results showed that irrigation of unconventional water resources exacerbated global warming potential (GWP). All exogenous substance treatments increased CO2 and CH4 emissions and suppressed N2O emissions, independent of the type of water, compared to no substances (NS). The inhibitors were ineffective in reducing the GWP whether or not in combination with biochar, and the combined application of inhibitors with biochar further increased the GWP. This study suggests that using inhibitors and biochar in combination to regulate the greenhouse effect under unconventional water resources irrigation should be done with caution.

Farmland ammonia (NH3) volatilization is an important source of NH3, and the application of chemical fertilizer nitrogen (N) is the main factor affecting NH3 volatilization. The optimal substitution of chemical fertilizer with organic manure and straw reportedly reduces NH3 volatilization, while reducing irrigation increases NH3 volatilization. However, the combined effect of nitrogen fertilizer substitution and reducing irrigation on NH3 volatilization and the role of microorganisms in this process remains unclear. In a soil column experiment, NH3 volatilization and microbial composition were measured under both multiple N sources and different irrigation levels by the vented-chamber method and metagenomic sequencing. The results revealed that multiple N sources application reduced cumulative NH3 volatilization by 16.5–75.4% compared to single chemical fertilizer application, and the decreasing trend of NH3 volatilization under reduced irrigation conditions was greater. Microorganisms had a more important effect on NH3 volatilization of reduced irrigation than conventional irrigation. The abundance of nirA, arcC, E3.5.1.49, and E3.5.5.1 (ammonia-producing) genes varied significantly at the two irrigation levels. Overall, multiple N sources could inhibit NH3 volatilization increasing under reducing irrigation compared to a single chemical fertilizer. Our findings contribute valuable insights into the combined effect of reduced irrigation and multiple N sources on NH3 volatilization.

High-risk antibiotic resistance genes (ARGs) in reclaimed water-irrigated soil pose a potential threat to ecosystem and human health. Inorganic fertilization – including with nitrogen, a key ingredient in agricultural production – may affect the ARG profile in soil. However, little is known about nitrogen fertilization's influence on ARGs profiles in the soil–plant system. This study investigated the effects of different nitrogen fertilizer types (CO(NH2)2, NO3–-N (NaNO3) and NH4+-N (NH4HCO3)) and different nitrogen fertilizer application rates (low, medium, high) on the distribution of high-risk ARGs in reclaimed water-irrigated soil and plants using quantitative PCR, high-throughput sequencing and metagenomic sequencing. Soil microcosms results revealed that nitrogen fertilization significantly affected the pattern of high-risk ARGs in soil, and also affected high-risk ARGs abundance and transfer capacity in plants. Compared with nitrogen fertilizer application rate, nitrogen fertilizer types significantly contributed to enhancing the soil resistome, with the order of CO(NH2)2 > NO3–-N ≈ NH4+-N. The medium application of NO3–-N and NH4+-N significantly reduced high-risk ARGs abundance in the leaf endophyte. Bacterial community mainly drove the variation of ARGs in nitrogen-fertilized soil–plant system, and class I integron and metal resistance genes (MRGs) also had direct effects on these high-risk ARGs. A similar high-risk ARGs pattern was also found in field plot experiments, and several dangerous pathogens were observed as the main high-risk ARGs potential hosts in nitrogen-fertilized soil. Based on an economic assessment, application of NH4+-N (NH4HCO3) could reduce costs by $1,312.83 ha−1 compared with NO3–-N (NaNO3). These results showed that the more important role of nitrogen type might be an effective and economical way to control high-risk ARGs spread in soil–plant system under reclaimed water irrigation.

Treated livestock wastewater reuse for irrigation and straw return in arid regions have become common practices worldwide. However, many uncertainties still exist regarding the effects of the returning straw sizes on heavy metal accumulation in soil and plants under treated livestock wastewater irrigation. In a pot experiment growing maize and soybean, large (5–10 cm), medium (1–5 cm), and small (<1 cm) sizes of wheat straw were amended to assess the changes in Cu and Zn distribution in the rhizosphere, bulk soils, and plants. Groundwater and swine wastewater were used as irrigation water resources. The results showed that irrigation with swine wastewater significantly reduced soil pH and increased the concentration of soil-available potassium. Concentrations of Cu in soil were more sensitive to swine wastewater and straw application than those of Zn in soil. Swine wastewater irrigation increased the accumulation of Cu and Zn in plants with higher concentrations of Zn, while straw return tended to inhibit this increase, especially when a small size of straw was employed. In addition to providing a reference for revealing the interaction mechanism between swine wastewater irrigation and straw return, this study proposes feasible solutions to improve the efficiency of agricultural waste recycling and realize sustainable agricultural development.

High frequent detection of sulfamethoxazole (SMX) in wastewater cannot be effectively removed by constructed wetlands (CWs) with a traditional river sand substrate. The role of emerging substrate of hematite in promoting SMX removal and the effect of influent SMX loads remain unclear. The removal efficiency of SMX in hematite CWs was significantly higher than that in river sand CWs by 12.7-13.8% by improving substrate adsorption capacity, plant uptake and microbial degradation. With increasing influent SMX load, the removal efficiency of SMX in hematite CWs slightly increased, and the removal pathways varied significantly. The contribution of plant uptake was relatively small (< 0.1%) under different influent SMX loads. Substrate adsorption (37.8%) primarily contributed to SMX removal in hematite CWs treated with low-influent SMX. Higher influent SMX loads decreased the contribution of substrate adsorption, and microbial degradation (67.0%) became the main removal pathway. Metagenomic analyses revealed that the rising influent load increased the abundance of SMXdegrading relative bacteria and the activity of key enzymes. Moreover, the abundance of high-risk ARGs and sulfonamide resistance genes in hematite CWs did not increase with the increasing influent load. This study elucidates the potential improvements in CWs with hematite introduction under different influent SMX loads.

The reduction of greenhouse gas releases from agricultural systems is of great significance in mitigating climate change. It is necessary to implement measures to mitigate carbon dioxide (CO2) and methane (CH4) emissions from soils irrigated using alternative waters, promoting the reuse of livestock wastewater and reclaimed water. The use of nitrapyrin, a nitrification inhibitor, and N-(N-butyl) thiophosphoric triamide, a urease inhibitor, has been explored to reduce greenhouse gas emissions. However, the impact of the inhibitor application on the soil carbon cycle as well as CO2 and CH4 emissions under alternative water irrigation remains unclear. To address this, a pot experiment with two consecutive cycles, irrigated with reclaimed water, livestock wastewater, and groundwater control was conducted. Nitrapyrin and/or N-(N-butyl) thiophosphoric triamide were applied to investigate the impacts of inhibitors on carbon cycle functional genes, soil properties, and CO2 and CH4 releases under alternative water irrigation. The results showed that inhibitor application increased the enrichment level of carbon degradation functional genes (xylA and cdh) and CO2 emission in the first cycle of this experiment, but had the opposite effect in the second cycle, regardless of the water type. The effects of increasing the relative abundance of methane-oxidizing genes (mmoX and mxaF) and lessening CH4 emissions were more pronounced when the nitrification inhibitor was applied alone. The combined application of inhibitors did not significantly promote the suppression of CO2 and CH4 emissions compared to a single application. Based on the structural equation model, soil NH4+-N and labile organic carbon were identified as key factors influencing the enrichment level of carbon cycle functional genes, as well as CO2 and CH4 emissions. This study suggests that soil labile organic carbon may influence the modulation of CO2 and CH4 releases by inhibitors and that multiple cycles of studies should be adopted when assessing the environmental impacts of inhibitors and alternative water irrigation.

The deep migration of soil nitrogen (N) poses a significant risk of N leaching, contributing to non-point-source pollution. This study examines the influence of microbial networks on the deep migration of chemical fertilizer N under varying irrigation management and multiple N fertilizer sources. A soil column experiment with eight treatments was conducted, utilizing 15N isotope labeling and metagenomic sequencing technology. The findings revealed that reduced irrigation significantly curbs the deep migration of chemical fertilizer N, and straw returning also mitigates this migration under conventional irrigation. Microbial network complexity and stability were markedly higher under reduced irrigation compared to conventional practices. Notably, network node count, average degree, and modularity exhibited significant negative correlations with the deep migration of chemical fertilizer N. The network topology indices, including node count, average clustering coefficient, average degree, modularity, and edge count, were found to be relatively more important for the deep migration of chemical fertilizer N. In conclusion, microbial networks play an important role in reducing the deep migration of chemical fertilizer N.

Agricultural utilization of reclaimed water is considered to be an effective way to solve water shortage and reduce water environmental pollution. Silicon fertilizer can improve crop yield and quality and enhance crop resistance. The effect of foliar spray with silicon fertilizer on phyllosphere microbial communities remains lacking. In this study, a pot experiment was conducted to explore the effects of different types of silicon fertilizer on the composition and diversity of a phyllosphere bacterial community and the abundances of related functional genes in rice irrigated with reclaimed water. The results showed that Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, and Verrucomicrobiota dominated the phyllosphere bacteria of rice. The relative abundance of Bacillus was higher than that of other treatments in RIS3. Reclaimed water irrigation significantly increased the relative abundances of the potential pathogens Pantoea and Enterobacter. The unclassified bacteria were also an important part of the bacterial community in the rice phyllosphere. Bacillus, Exiguobacterium, Aeromonas, and Citrobacter were significantly enriched by silicon fertilizer treatments. Functional prediction analysis showed that indicator species were mainly involved in metabolism and degradation functions, and the predicted functional groups of phyllosphere bacteria were attributed to chemoheterotrophy, aerobic chemoheterotrophy, nitrate reduction, and fermentation. Quantitative PCR results showed that AOA, AOB, and nifH genes were at low abundance levels in all treatments, and nirK genes was not significantly different among treatments. These results contribute to the in-depth understanding of the effects of foliar spray silicon fertilizer on the bacterial community structure and diversity of rice phyllosphere and provide a theoretical basis for the application of silicon fertilizer in reclaimed water irrigation agriculture.

再生水灌溉是缓解水资源矛盾的有效途径,为表征再生水灌溉后土壤粒度分布(Soil particle size distri-bution,PSD)特性,通过室内土柱模拟试验,设置生活污水(W1)、再生水 1(W2)和再生水 2(W3)共计 3 种灌溉水质,并以自来水(W4)作为对照,采用马尔文激光粒度仪测定灌溉 1a后各处理土壤颗粒百分比,运用分形理论分析了 4种水质处理下土壤PSD的分形特征.结果表明:(1)4 种水质处理下土壤PSD呈单峰分布;与W4 处理相比,W1、W2、W3 处理下土壤黏粒含量增加 0.40%～6.38%,砂粒含量降低 1.58%～13.80%,土壤非均匀性增强,但各处理间差异不显著.(2)再生水灌溉下土壤颗粒呈细粒化趋势,土壤PSD多重分形参数增大,土壤PSD趋于不均匀.在 0～10 cm土层,W3 处理下土壤PSD多重分形参数容量维数D(0)、信息维数D(1)、相关维数D(2)和多重分形奇异谱宽Δα(q)最大,分别为 0.943、0.837、0.823 和 1.035;在 10～20 cm土层,W2 处理下D(0)、D(1)、D(2)和Δα(q)最大,分别为0.943、0.851、0.852 和1.009.(3)土壤PSD的多重分形参数D(0)、D(1)、D(2)、Δα(q)和α(0)与土壤黏粒含量呈显著正相关,与砂粒含量呈显著负相关,土壤分形特征由土壤中黏粒与砂粒的相对含量控制.研究表明,在试验期内,再生水灌溉下土壤PSD的空间异质性与非均匀性增大,可以通过多重分形参数进行定量表征.

Environmental hazards and remediation of pharmaceuticals and personal care products（PPCPs）have recently received growing attentions. Thus, investigating the purification effect of azolla on domestic sewage containing PPCPs is important. Representative PPCPs gemfibrozil, carbamazepine, and azolla were used as test materials, and indoor simulation culture tests were conducted to investigate the growth of azolla in domestic wastewater at both different incubation times（1, 2, 4, and 8 d）and different initial concentrations of PPCPs(0,1, 10, 100, and 1 000 μg·L -1 ), as well as the removal rates of conventional pollutants（ammonia nitrogen, NH3-N; nitrate nitrogen, NO 3 --N;total phosphorus, TP; chemical oxygen demand, COD）and PPCPs. With an increase of the initial concentration of PPCPs in domestic wastewater, the relative growth rate and tolerance index of azolla showed a trend of first increasing and then decreasing, and the growth of azolla was inhibited under the treatment of 100 and 1 000 μg · L -1 PPCPs. Compared with the control, the removal effect of azolla on nitrogen and phosphorus was significantly enhanced under 1 and 10 μg·L -1 PPCPs treatment（P＜0.05）, but was significantly weakened under100 and 1 000 μg·L -1 PPCPs treatment（P＜0.05）. When treating with different initial concentrations of PPCPs, the effect of azolla on COD removal was significant, and the COD removal rate increased with the increase of the initial concentration of PPCPs. The removal effect of azolla on gemfibrozil and carbamazepine was enhanced with increasing incubation time. The removal rate of gemfibrozil increased with increasing initial concentration of PPCPs(except for 1 000 μg·L -1 PPCPs treatment), whereas the removal rate of carbamazepine decreased with increasing initial concentration of PPCPs. Azolla has a good removal effect on both PPCPs and conventional pollutants other than ammonia nitrogen in domestic wastewater and can be used as a remediation treatment plan for domestic wastewater containing typical PPCPs.

The transfer of antibiotic resistance genes (ARGs) in soil under reclaimed water irrigation poses a potential environmental risk. Regulation of NPK fertilizer could influence the behavior of bacterial communities, mobile genetic elements (MGEs), and soil properties, which determine the fate of ARGs. To identify the key element in NPK fertilizer and realize efficient regulation, we explored the effect of individual N, P, K fertilization on ARG variation in tomato rhizosphere and bulk soils. Compared with an unfertilized treatment, N fertilization resulted in greater decreases in the abundance of ARGs (decreases of 24.06%-73.09%) than did either P fertilization (increases of up to 35.84%, decreases of up to 58.80%) or K fertilization (decreases of 13.47%-72.47%). The influence of different forms of N (CO(NH2)2, NaNO3, and NH4HCO3), P (Ca(H2PO4)2 and CaMgO4P+), and K (KCl and K2(SO4)) fertilizers was also investigated in this study, and showed the influence of NaNO3, CaMgO4P+, and K2(SO4) on reducing ARGs abundance was greater in different types of N, P, K fertilizers. Bacterial communities showed the strongest response to N fertilization. The reduced bacterial diversity and abundance of ARG-host and non-host organisms explained the decline of total ARG abundance in soil. In soils fertilized with either P or K, the effect of soil properties, especially total nitrogen and pH, on ARG variation was greater than that of bacterial community and MGEs. These results suggest that N regulation of in NPK fertilizer may be an effective way to reduce the risks of ARGs in soil associated with reclaimed water irrigation.

土壤盐渍化问题已成为制约新疆地区农业发展的主要因素,近年来生物炭在改良土壤方面发挥了极大优势.为研究不同生物炭施用量对土壤理化性质以及盐分分布的影响,于2018-2020年在新疆地区开展生物炭改良盐碱土试验,种植作物为棉花-甜菜间作,模式为当地传统"一膜两管四行"栽培模式.2018年试验设置4个生物炭水平,分别为0、10、50、100 t/hm2o 2019年增加设置25 t/hm2.综合分析2018年和2019年的试验结果,2020年生物炭施用量调整为0、10、25、30t/hm2.生物炭混合深度为30 cm.在作物的不同生育期对各个处理不同剖面深度取土测定电导率、pH值和有机质含量,分析不同生物炭施用量对土壤pH值、有机质和盐分的影响.结果表明,添加生物炭显著降低生育初期和生育末期0～30 cm 土层的pH值,且降低幅度与生物炭施用量成正比.生物炭对30～40 cm 土层的pH值有降低作用,但效果不显著.因生物炭自身有机质丰富,生物炭施用10～100 t/hm2可增加土壤有机质含量31.8％～135.8％.土壤含盐量在垂直方向上,表现出浅层大、深层小的一致性规律;在水平方向上,膜间土壤含盐量大于滴头附近的土壤含盐量.与对照处理相比,生物炭处理增加了 0～10 cm、0～40 cm和0～100 cm深度的加权平面含盐量,3年分别增加13.9％～79.2％、6.6％～133.6％和4.7％～103.5％.施用生物炭后可促进盐分淋洗,当施用量为10、25t/hm2时,脱盐率为14.7％～22.3％,较其他生物炭处理高.综合考虑盐分淋洗和生物炭施用的经济成本,生物炭适宜用量推荐为10 t/hm2.

Due to reclaimed water, irrigation can cause human health and environmental risks. Soil amendments are applied to reveal the abundance of pathogens and antibiotic resistance genes in rhizosphere soil irrigated by reclaimed water and to better understand the effects of environmental factors on the rhizosphere soil bacterial composition, which has guiding significance for the reasonable use of soil amendments. In this study, the effects of biochar, bioorganic fertilizer, humic acid, loosening soil essence, and corn vinasse on bacterial community diversity and certain gene abundances in rhizosphere soil under drip irrigation with reclaimed water were studied using high-throughput assays and quantitative PCR. The results showed that biochar significantly increased pH, organic matter, and total nitrogen contents in the rhizosphere soil. The corn vinasse significantly decreased soil pH and increased the contents of total nitrogen and total phosphorus but significantly increased the soil EC value (P<0.05). The effects of the five soil amendments on the α-diversity of rhizosphere bacteria were not significantly different. The bacterial community structure and diversity of rhizosphere bacteria were similar at different taxonomic levels, but their relative abundance was different. α-Proteobacteria, γ-Proteobacteria, Bacteroidia, Actinobacteria, Acidimicrobiia, and Anaerolineae were the dominant bacteria in all treatments. The dominant genera consisted of Pseudomonas, Sphingobium, Sphingomonas, Cellvibrio, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Flavobacterium, and Algoriphagus (relative abundance>1%). Correlation analysis of environmental factors showed that the composition of the rhizosphere bacterial community was strongly correlated with pH, EC, total nitrogen, and total phosphorus content. The abundances of pathogenic bacteria and antibiotic resistance genes were 103-107 copies·g-1 and 104-108 copies·g-1, respectively. There were significant differences in the detection levels of pathogens and antibiotic resistance genes. Bioorganic fertilizer, loosening soil essence, and corn vinasse significantly increased the abundances of some antibiotic resistance genes, whereas humic acid and corn vinasse significantly decreased the abundances of Pseudomonas syringae, Ralstonia solanacearum, and total coliforms (P<0.05). A significant correlation was found between pathogens (Arcobacter, Bacillus cereus, Pantoea agglomerans, and Fecal bacteroidetes) and antibiotic resistance genes (tetA, tetB, tetO, tetQ, sul1, ermB, and ermC). In conclusion, while monitoring pathogens and antibiotic resistance genes in the agricultural environment under reclaimed water irrigation, attention should be paid to the rational application of soil amendments to avoid exacerbating the spread of biological contamination.

随着药品和个人护理品(Pharmaceuticals and Personal Care Products,PPCPs)生产和使用量的增加,PPCPs及其代谢产物在再生水中的检出种类、检出量不断增多,再生水灌溉可影响PPCPs在土壤-作物(蔬菜)系统中的分布及累积,但其规律及驱动机制尚不明确.为探明再生水滴灌条件下滴头布置方式对PPCPs在土壤-作物(蔬菜)系统累积的影响,该研究采用盆栽试验比较2种滴头布置方式(在番茄根部、在两番茄中间)对土壤剖面及番茄各器官中PPCPs累积量的影响,并进一步分析PPCPs在土壤-作物(蔬菜)系统累积的驱动机制.结果表明,再生水灌溉条件下不同滴头布置方式造成了PPCPs在土壤、作物(蔬菜)中累积规律的差异性,滴头布置在两番茄中间处理较其他处理而言增加了0～5 cm土层吉非罗齐累积量(P<0.05),降低了番茄叶部卡马西平和根部吉非罗齐的累积量(P<0.05),较滴头布置在番茄根部处理降低了番茄叶部吉非罗齐和根部三氯生的累积量(P<0.05);不同再生水灌溉方式通过影响土壤微环境指标导致了土壤中PPCPs分布规律的差异性,滴头布置在植株中间处理较其他处理增加了0～5 cm土层pH值,导致该土层下吉非罗齐的累积量高于其他处理(P<0.05).研究可为基于新兴污染物PPCPs防控的再生水农业安全利用提供理论依据.

随着药品和个人护理品(PPCPs)生产和使用量的增加,PPCPs及其代谢产物在水体、土壤环境中的检出量、检出种类与日俱增.本文基于国内外已有的相关文献,总结了典型PPCPs通过不同途径进入土壤-作物系统的环境风险,并从PPCPs在土壤-作物系统中的降解行为特征和迁移累积规律等方面对PPCPs环境行为及归趋的最新研究进展进行了综述,指出目前研究存在的PPCPs种类、浓度、输入方式以及环境背景的单一性等突出问题,并对该领域未来研究趋势进行了展望,如不同类别PPCPs的环境行为特征、与土壤微环境的互作机制、降解或螯合产物及其环境行为与风险等方面的研究,对于探明PPCPs对生态环境的影响规律及对人类健康的潜在危害具有重要意义.

Phenology is one of the prominent indicators for studying the impact of climate change on crop production. Based on cotton phenology and meteorological data from 79 agricultural weather stations in China between 1981 and 2017, the Pearson correlation, multi-variate linear regression and path analysis are applied to investigate the spatial and temporal changes of cotton phenological indices and climate variables (precipitation (Pre), sunshine duration (Sun), average (Tave), minimum (Tmin) and maximum temperatures (Tmax), influence degrees of Pre, Sun, and Tave on phenology, and isolated effects of climate change and crop management on cotton phenology. The results showed that: (1) Emergence (Eme), squaring (Squ), flowering (Flo), and boll opening (Bol) dates of cotton advanced by 0.026–0.351 days year−1, respectively. The cotton sowing (Sow) and maturity (Mat) dates were delayed by 0.170 and 0.337 days year−1. The average phenological stages from Sow-Eme, Squ-Flo, and Flo-Bol were shortened about 0.19–0.30 days year−1, Eme-Squ, Bol-Mat and the Sow-Mat were delayed by 0.11, 0.77, and 0.082 days year−1, respectively. (2) Pre had a positive effect on most of the lengths phenological stages of cotton except during Bol-Mat. The effect of Sun on the length of the various phenological stages of cotton was the opposite of that of Pre. Tave, Tmin, and Tmax on the general negative effects on the length of the cotton phenological stages. (3) Pre, Sun, and Tave had different influence degrees on the cotton phenological stages because of different regional climate characteristics. (4) The impact of climate change on cotton phenology was weaker than crop management or combined effects of climate change and crop management. Under the combined impacts, and isolated impact of crop management, the lengths of the stages from Sow-Eme and Squ-Flo were shortened while other phenological stages were extended. The isolated impact of climate change shortened the lengths of stages from Sow-Eme, Eme-Squ, and Flo-Bol, extended Squ-Flo, Bol-Mat, and Sow-Mat, implying that the longer-duration cotton varieties in a changing climate might be a better choice for planting. This could be a viable strategy for adapting to climate change. In addition, the study found that Seed cotton yield (Scy) decreased with the delay of Sow, Eme, Squ, Flo and Bol dates, increased with the increase of the lengths of Sow-Eme, Flo-Bol, Bol-Mat and Sow-Mat. And the change trend of Scy affected by climate change was less than that affected by crop management or combined effects.

为了探讨淡水资源匮乏地区微咸水与再生水的安全合理利用，通过盆栽上海青试验，以清水灌溉为对照，设置再生水灌溉（T1）、微咸水—再生水1∶2灌溉（T2）、微咸水—再生水1∶1灌溉（T3）、微咸水灌溉（T4）4种灌溉方式，研究了不同比例微咸水与再生水混合灌溉对土壤水盐、作物生物量（地上部和地下部）、叶片叶绿素含量、可溶性蛋白含量、丙二醛（MDA）含量、过氧化氢酶（CAT）活性、超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性的影响。结果表明：（1）上海青收获后，不同比例微咸水与再生水混合灌溉处理土壤含水率和含盐量较清水灌溉（CK）均有所升高，其中T1、T2、T3处理土壤含水率与CK差异不显著，T4处理土壤含水率较CK差异显著（P<0.05），而各处理土壤含盐量与CK均差异显著；与T1处理相比，随着灌溉水中微咸水比重的升高，土壤含水率逐渐升高，且至T4处理时差异显著。（2）微咸水与再生水混灌对上海青地上部鲜重有一定影响，而对地上部干重以及地下部生物量无显著影响。与T1相比，T2、T3、T4处理上海青地上部鲜重均显著降低（P<0.05），降幅为24.78%~26.36%，地上部干重亦均降低，但差异不显著，降幅为19.14%~24.54%，地下部鲜重和干重无显著性变化。（3）微咸水与再生水混灌对上海青生理指标（叶绿素含量、可溶性蛋白含量、MDA含量、POD活性、CAT活性）没有显著影响，对SOD活性具有显著的提升作用。与T1相比，T2、T3、T4处理叶绿素a含量分别降低4.98%，3.82%和9.26%，叶绿素b含量分别降低10.88%，8.20%和13.46%，叶绿素总量分别降低9.76%，6.12%和10.15%，CAT活性分别提高8.51%，8.51%和-19.15%，POD活性分别提高1.92%，17.24%和-2.87%，SOD活性分别提高104.07%，62.20%和41.67%。随着混合液中微咸水比重的升高，上海青可溶性蛋白含量先降低后升高，MDA含量先升高后降低。（4）基于第二代综合生物响应指数（integrated biological response version 2，IBRv2），综合考虑土壤水盐、作物生理指标以及再生水资源本身的局限性，在淡水资源匮乏地区利用微咸水灌溉时，可以考虑用再生水作为替代清水水源与微咸水配合使用，微咸水—再生水混灌比例以1∶1为宜。研究结果可为淡水不足地区利用微咸水（3 g/L）灌溉提供参考。