The land-use of organic fertilizers is considered as an important sustainable method for resource utilization, which may have an impact on the microplastic behaviors in the soil. Here, a 240-d dark culture experiment was conducted to reveal the degradation and biofilm characteristics of degradable and refractory granule microplastics in soil and soil-fertilizer systems. The results indicated that microplastics generally exhibited a weak weight loss as well as a specific etiolation on the surface after the culture, especially polyvinyl-chloride and polyhydroxyalkanoates (PHA). Increase in carbon-oxygen functional groups and the changes of oxygen/carbon ratios were noticed, which implied that oxidation and degradation occurred on the surface of microplastics during the cultural process. The changes were more intense on the degradable PHA, and the fertilized-soil treatment than those of the refractory microplastics and the pure soil. Moreover, the addition of organic fertilizers enriched the community diversity of bacterial biofilm on multiple microplastic surfaces. In this regard, the animal fertilizers provided a stronger effect than the plant fertilizers. Overall, the soil, fertilizer and microplastic types affected the community structure and diversity of bacterial biofilm. The outcomes of this study would provide a theoretical basis for the utilization of organic matters for agricultural soil applications.

The conjugated steroid estrogens (CSEs), including estrone sulfate sodium (E1-3 S) and 17 & beta;-estradiol-3-O-sulfate sodium (E2-3 S), exhibit distinct metabolic behaviors in the aqueous and soil environments. However, their assimilation behaviors and metabolite formations in plant bodies (shoots and roots) remain poorly understood. Therefore, this study used a modified plant hydroponic system to explore the efficiency with which wheat (Triticum acstivnm L.) assimilated the two estrogen conjugates, E1-3 S and E2-3 S. Results indicated the potential of wheat to absorb E1-3 S and E2-3 S, with their assimilation in the root being significantly higher (104-105 ng/g dw) than in the shoot (103-104 ng/g dw). E1-3 S de-sulfated and transformed to estrone (E1) at a rate of 4%-45% in the root's oxidative environment, whereas E2-3 S converted to E1-3 S at 210%-570%. However, the root-toshoot transfer was impeded by a less potent metabolic activity within the shoot system. The co-exposure treatment revealed that E1 or 17 & beta;-estradiol (E2) affects the assimilation of E1-3 S and E2-3 S by wheat, with E1 inhibiting E1-3 S assimilation and E2 promoting E2-3 S assimilation in wheat bodies. Nonetheless, free-form steroid estrogens (FSEs), which typically have a significant hormone action, can oxidative-damage the wheat tissues, producing a progressive wilting of wheat leaf and so limiting the transpiration process. Co-exposure initially increased the assimilation amounts of E1-3 S (particularly in shoots) and E2-3 S (in both roots and shoots), but these values rapidly declined as exposure duration increased. The combined effects of E1-3 S and E23 S exposure also increased their assimilation. These findings suggest the need for further investigation into the cumulative impact of environmental estrogen contaminants. The findings of present study can potentially guide the development of strategies to prevent and manage steroid estrogen contamination in agricultural contexts.

Residual steroid estrogens (SEs) in soil may be absorbed by plants, and subsequently threaten human health via food chains. However, the environmental behavior of SEs in soil-plant systems remains unclear. In this study, a wheat pot experiment using rhizosphere bags was performed to investigate the uptake and dissipation of target SEs (17 beta-estradiol (E2) and estrone (E1)) in different soils. The results indicated that soils with higher organic matter and silt and clay reduced the plant uptake of estrogens. Compared with E1, E2 was less accumulated in plants, which was mainly correlated with its higher hydrophobicity and shorter half-life. Estrogens tended to concentrate in the plant roots instead of translocating to the shoots. In addition, plant cultivation enhanced estrogen dissipation in the rhizosphere with an improvement of 10-21%. This improvement mainly resulted from stimulating the activities of estrogen-degrading enzymes, increasing the total bacterial populations, and promoting the development of estrogen degraders. Furthermore, this promotion effect will increase with plant growth. These findings will help us understand the characteristics of SEs taken up by plants and the role of the rhizosphere in SEs elimination, and provide theoretical insights into reducing the pollution risk of SEs in agricultural soils.

以西蓝花为对象,研究了露地菜田不同施肥方式下土壤氮转化酶、氮转化功能基因及氮吸收量的差异,监测了西蓝花生育期内不同时期0～100 cm 土壤硝态氮含量动态变化.结果表明:①施氮处理(CF、CU80％和CU60％)土壤脲酶活性是缺氮处理(PK)的1.78～3.11倍,差异显著(p＜0.05),并且其AOA、AOB、nirS、nirK和nosZ丰度分别较PK处理分别增加了26.35％～50.98％、57.69％～126.73％、50.76％～120.79％、31.41％～118.07％和39.45％～282.95％.减氮20％控释掺混肥一次性底施处理(CU80％和CU60％)与传统底追结合施肥处理(CF)之间的脲酶活性和氮转化功能基因丰度均无显著差异(p＞0.05).②不同施肥处理植株全氮含量和吸氮量无显著差异(p＞0.05).③与CF处理相比,CU80％处理提高了0～20cm土壤硝态氮供应,其含量是CF处理的1.97～15.22倍.④试验开始后第31 d,施肥、灌溉和降雨导致试验地块40～60 cm和60～80 cm土壤硝态氮平均含量分别增加到种植前的3.37倍和7.33倍,且80～100 cm 土壤硝态氮含量高达23.22 mg·kg-1.西蓝花采收后,试验区各土层硝态氮平均含量均降到8mg·kg-1以下,表明西蓝花种植期间发生了明显的硝酸盐淋溶.⑤追肥、灌溉和降雨导致CF处理40～60、60～80和80～100cm土壤硝态氮含量分别增加到55.98、51.69和36.04 mg·kg-1,而CU80％处理相应土层的硝态氮含量分别仅为CF处理的5.91％、18.61％和26.69％.综上结果表明,减氮20％控释掺混肥一次性底施(CU80％)在满足土壤氮转化、耕层氮供应和作物吸氮的前提下,有效削减了硝态氮淋溶,显著降低了农田面源污染.

The use of organic fertilizers is becoming a routine measure of soil improvement in China, and therefore organic fertilizers are considered an emerging contributor to microplastic accumulation in farmland soils. However, little is known regarding the microplastic contents in organic fertilizers used across China. Here, we investigated the occurrence and distribution of microplastics in 102 organic fertilizer samples across 22 provincial administrative regions of China to serve as a basis for the development of better microplastic management strategies. Organic fertilizers are made of a wide variety of feedstocks, including livestock manure (chicken, cow, goat, and pig manure) and bacterial residues etc., and are mainly produced via aerobic composting. In present study, microplastics within a 0.1-5 mm range in different types of organic fertilizers were separated using a general sequential density flotation method. Microplastic abundances ranged from undetectable to 2550 items/kg, with an average value of 325 ± 511 items/kg and a detection frequency of 80.4 %. The highest microplastic abundances were detected in Beijing City (758 items/kg) and in compound organic fertilizers (average of 386 items/kg). The microplastics in organic fertilizer were primarily white/transparent (75.9 %), 1-3 mm in size (55 %), and film-shaped (39 %). Interestingly, microplastics were not detected in cow dung fertilizer, suggesting that cow dung-based fertilizers might generally contain lower microplastic levels. Moreover, organic fertilizer microplastics tended to be concentrated in provincial areas with intensive agriculture, and the input flux of microplastics from organic fertilizer into fertilized soils reached an average of 5.07 × 1012 items per year. Collectively, our findings provide key insights into the current state of microplastic levels in organic fertilizers in China and serve as a basis for the creation of novel microplastic mitigation strategies in farmland soils.

为探索露地结球生菜轻简高效的养分管理措施,选择京郊生菜种植园区,设置不施氮对照(CK)、常规施肥(CF)、常规减肥(-20％CF)和控释掺混肥(-20％CU)4个处理,研究了控释掺混肥一次性减量施肥对结球生菜产量、品质、叶片生理特征、养分吸收、土壤硝态氮残留的影响.结果表明,与常规施肥相比,在氮、磷、钾肥减量20％的情况下,控释掺混肥处理的结球生菜总产量和经济产量分别提高2.32％和3.28％,硝酸盐含量显著降低29.98％.在结球生菜生长期内,控释掺混肥处理在不同生育期(苗期、莲座期、结球中期和收获期)的结球生菜叶片叶绿素含量和氮代谢酶活性(谷氨酸合成酶、硝酸还原酶、亚硝酸还原酶、谷氨酸合成酶、谷氨酸脱氢酶和谷氨酰胺合成酶)与常规施肥差异不大,在结球生菜收获后,所有处理在0～100 cm土体内的残留硝酸盐含量总体不高,相对来说,控释掺混肥处理有一定的硝酸盐淋洗风险.综上所述,控释掺混肥一次性减量施肥在稳定结球生菜产量的前提下,可显著提升生菜品质,在规模化结球生菜生产中具有较大的应用价值.

以2014年、2017年260份调查问卷和582个土壤样品及年度农用化肥总量为依据,梳理了昌平区年际间施肥量、土壤养分、氮磷环境风险和污染源变化,以期为北运河上游化肥面源污染防控提供理论依据.结果表明,相比于2014年,2017年粮食、果类蔬菜、叶类蔬菜和草莓的化肥平均用量分别减少了26.3％、25.5％、20.4％和15.0％,蔬菜和草莓的有机肥平均用量分别减少了42.6％和6.67％.粮田和菜地氮盈余均为无风险,2017年氮素地下淋溶和地表径流损失相比于2014年分别减少了27.8％和56.0％.粮田不存在磷环境风险,菜地磷环境风险等级从2014年的高风险降至2017年的中风险.与2014年相比,2017年污染物流失量降低了47.8％.区域地表水环境均以总氮污染为主,其次是总磷和氨氮.本研究提出在夏玉米上推广环境友好型肥料和免耕措施;对果类蔬菜采取养分总量控制与分期调控的施肥策略;引导叶菜生产采用滴灌或微喷;开展草莓与多种作物间套作,加大土壤盈余氮、磷的吸收;探索建立推动土肥社会化服务的应用.

类固醇雌激素(steroidal estrogens,SEs)作为典型的内分泌干扰物,在环境介质中被广泛检出,其进入生物体后可模拟细胞内源性激素作用对生物体生长、发育、生殖等产生不利影响,因此越来越引起关注.目前关于SEs的研究报道多集中于粪便、土壤、水体等介质中的检出及环境行为,以及SEs在水生生物体内的迁移和转化,其累积效应及其机制研究较为系统和全面.相较而言,SEs在土壤-植物体系中的迁移累积报道较少,但是对于掌握农田系统中SEs迁移转化的需求更为迫切.结合现有的国内外相关研究,总结了SEs在土壤-植物体系中的吸收累积和迁移转化行为特征,概述了植物吸收代谢SEs的影响因素以及SEs对植物生长发育的毒理效应.目前针对SEs的植物体吸收大多数仍基于室内模拟实验,对于其在土壤-植物多相态体系中迁移转化机理尚不清楚.因此,对今后的研究方向提出以下几点建议:(1)除室内模拟实验外,对实际土壤-植物系统中的研究更具价值,特别是SEs土壤-土壤水-植物多相态体系中的迁移转化等过程;(2)应结合SEs的来源,探究畜禽粪便、城市污泥及污水等不同源SEs对植物吸收、累积污染物的影响及污染风险;(3)加强对农作物体内SEs残留的监测和风险评估,制定SEs农作物检出及人体摄入的相关标准.

试验选取基质栽培番茄与青椒,进行为期两年的施肥试验,研究京郊 日光温室简易基质栽培模式下果类蔬菜产量与表观养分平衡.结果表明:①基质栽培处理较土壤栽培处理节水53.4％、减少化肥投入21.1％～26.4％、增产11.1％～23.8％、化肥偏生产力提高45.7％～61.4％;②基质栽培处理降低了 74.2％～81.0％氮盈余、66.6％～71.2％磷盈余,并且降低了 70％以上土壤硝态氮、速效磷累积,可以有效减少进入水体的氮磷养分.简易基质栽培是符合日光温室环境条件,并且高产、环境友好的栽培模式,本研究为北京市日光温室基质栽培果类蔬菜生产、肥料面源污染防控提供生产模式与科学依据.

为探索包膜尿素掺混肥料在露地西蓝花规模化生产中的应用潜力,提高西蓝花大规模生产中轻简化施肥水平,对比研究了包膜尿素掺混肥料一次性底施和常规施肥方式下,西蓝花的产出(综合采收指数和产量)、品质(硝酸盐和维生素C含量)、成本、净经济效益以及不同生育期土壤耕层硝态氮供应和植株养分吸收量变化.结果 表明,包膜尿素(释放期60天)与磷酸二铵、硫酸钾掺混一次性底施,西蓝花综合采收指数为54.67,亩产量为1.65 t,较常规施肥增加3.96％;硝酸盐含量为634.52 mg/kg,较常规施肥降低2.14％;维生素C含量为335.45 mg/kg;亩节省追肥用工成本180元,亩增加肥料成本32.73元,综合亩节本147.27元,亩增加净经济效益373.2元,增幅12.28％;苗期和莲座期耕层土壤硝态氮含量分别是常规施肥方式的2.7倍和3.2倍;苗期、莲座期和花球采收期植株的养分吸收量与常规施肥方式无差异.综上,包膜尿素掺混肥一次性底施,可稳定西蓝花产量和品质,保障不同生育期土壤的氮素供应和植株的养分吸收,节本增效效果显著,在露地西蓝花规模化生产中具有较大的推广应用价值.

为探讨生物炭对农田化肥面源污染的防控效果,本文以北运河流域(北京段)下游"上壤下砂"、施肥量大、易漏水漏肥菜田为研究对象,分析了田间条件下不同用量生物炭配合化肥底施和施炭基肥对土壤氮磷纵向迁移、结球生菜产量品质及土壤微生物数量的影响.结果表明:与单施化肥(T1)相比,①化肥配施生物炭750 kg·hm-2(T2)、2250 kg.hm-2(T3)、4500 kg.hm-2(T4)和施炭基肥(T5)处理20～40 cm 土壤硝态氮含量分别降低41.20％、39.60％、24.20％和 13.78％,0～20 cm土壤有效磷(Olsen-P)含量分别提高26.30％、24.70％、32.60％和 11.20％,40～60 cm土壤Olsen-P含量分别减少27.30％、26.10％、33.50％和41.30％,T3和T5处理20～40 cm土壤Olsen-P含量分别减少19.90％和12.50％,表明农田配施生物炭或者施炭基肥可提高耕层土壤供磷量,并有效阻控耕层硝态氮和Olsen-P向下层土壤淋溶迁移;②化肥配施生物炭(T2～T4)对结球生菜产量、维生素C(Vc)和硝酸盐含量均无显著影响,施炭基肥(T5)处理结球生菜生物产量显著增加了14.36％(p<0.05),Vc含量显著提高了20.00％(p<0.05);③T4和T5处理土壤细菌数量分别减少57.49％和47.50％(p<0.05),且T5处理土壤真菌数量减少46.67％(p<0.05).综合考虑不同土层氮磷、结球生菜产量品质及土壤微生物数量变化,推荐生物炭配施量为750?2250 kg?hm-2,并建议进一步加强生物炭对农田土壤微生物群落的影响监测.

类固醇雌激素作为一种典型的内分泌干扰物,在环境介质以及植物体内不断被检出,具有极大的生态风险.按形态划分,类固醇雌激素可分为自由态和结合态,本文围绕类固醇雌激素的形态特征,从以下3个方面对以往的相关研究进行了综述:总结了人类和畜禽动物类固醇雌激素的排放特征,阐述了自由态和结合态雌激素理化性质的异同之处;系统描述了自由态和结合态雌激素在土壤和水体两种环境介质中的吸附、降解、迁移、转化等环境行为和相关影响因素;针对两个不同的排放源——城市污水厂污水、污泥以及畜禽养殖场粪污,分析并总结了类固醇雌激素的控制技术和方法.

To understand the potential environmental influence of animal manure under freeze-thaw cycles, pig manure was used to conduct a simulation experiment to explore the effects of freeze-thaw cycles on heavy metal distribution and form transformation. Thirty cycles of freezing and thawing were performed alternately by freezing at − 18 ± 2 °C for 24 h and thawing at 20 ± 2 °C for 24 h. By a serial wet sieving procedure, manure samples were separated into different sizes of 1000, 250, 75, 38, and < 38 μm. Solid samples were collected from the dry matter at each stage of sieve; then the washing waters were collected as liquid samples accordingly. The concentrations of heavy metals in solid/liquid samples and their five forms were analyzed. It showed that the concentrations of heavy metals in the solid and liquid samples gradually increased because of organic matter degradation during freezing and thawing cycles. The distribution of heavy metals on particles of different sizes was also affected by the degradation and breakup of pig manure; the metals showed a tendency to aggregate in small particles (< 38 μm). Among them, the percentage of Cu and Zn on < 38 μm particles increased by 162.3% and 554.1%, respectively. After several freeze-thaw cycles, the concentrations of EXCH-X (metals of exchangeable form) increased significantly, those of CARB-X (carbonate-bound form) and Fe/Mn-X (Fe/Mn oxide-bound form) decreased accordingly. These form transformations may be largely influenced by the enhancement of dissolved organic matter (DOM) and the reduction of pH value. Therefore, frequent freeze-thaw cycles may promote the mobility and bioavailability of heavy metals in pig manure. The results are significant for understanding the pollution risk of pig manure in the freeze-thaw regions.

Applying sewage sludge or animal manure onto agricultural land can result in estrogen pollution, which increases the risk of human exposure to steroid estrogens (SEs) via the food chain. However, the uptake and accumulation mechanism of SEs by plants is still unclear. In this study, the uptake, accumulation, and translocation of 17β-E2, a representative SE, were investigated through a series of wheat hydroponic experiments. Various inhibitors were applied to explore the uptake pathways of 17β-E2 by wheat. In addition, the effects of exposure concentrations, coexisting 17α-ethynylestradiol (EE2) and plant properties on the uptake of 17β-E2 were examined. The results indicated that the accumulation of 17β-E2 in wheat roots mainly resulted from adsorption and active uptake that involved aquaporins and anion channels transport. The chlorophyll and protein contents of plants were positively correlated with the uptake of 17β-E2, whereas competitive inhibition occurred when 17β-E2 and EE2 coexisted in the same solution. Nevertheless, the results of a split-root experiment showed that 17β-E2 absorbed by wheat could further migrate in plant via long-distance transport and ultimately was discharged from plants, suggesting that 17β-E2 was still at risk of being released even though it had been absorbed by plants. These results could provide valuable insights into the risk assessment and risk control of the uptake of SEs by plants.

Soil erosion on sloping land induces soil and water loss and non-point pollution, causing serious adverse effects on ecology and environment quality in hilly areas. Use of plant hedges or filter strips is an effective method to prevent soil and water loss and to protect ecology and environment quality. It can effectively increase soil infiltration and reduce the runoff, sediment, nitrogen (N), phosphorus (P), and pollutants through the combined action of plants, soil, and microorganisms. This manuscript summarizes the effectiveness of different plant hedges and filter strips in reducing the runoff, sediment, N, P, and pollutants, analyzes the associated impact factors, discusses the interrupting mechanisms, and, finally, proposes contents that need further study in the future. It can provide a reference for further research and the application of plant hedges or filter strip technology and provides evidence for sustainable utilization of cultivated land and ecological agriculture construction in hilly areas.

The variations of phosphorus (P) in animal manure during freeze-thaw cycles (FTCs) profoundly influence on non-point source P loss in winter. Therefore, understanding how FTCs influence the physicochemical properties of animal manure and its P availability is crucial. In this study, the freeze-thaw treatment was performed by incubating the pig manure at -20 °C for 12 h and at 18 °C for 12 h. The freeze-only treatment was maintained at -20 °C as a control. In addition, the pig manure was kept at two moisture levels during the FTCs and sampled every five cycles. Six forms of P in the manure were extracted and analyzed. After 30 cycles, the dissolved organic carbon had increased from 10.49 to 13.56 g/kg, and the pH had decreased from 6.25 to 5.77. The particles originally >1000 μm were broken into particles <250 μm. The forms of P in manure shifted from Ca-P, occluded P, and residual P towards NH4Cl-P, Al-P and Fe-P, resulting in a 23% increase in bioavailable P. These variations were highly coincident with the increase in moisture content and FTC frequency. The proportion of particles <38 μm increased by more than 2% after the FTCs, and the manure P was mainly concentrated in these particles, which might be readily washed away by the melt water. Overall, the study indicated that FTCs could enhance the bioavailability of P in pig manure and the mobility of particle-associated P. These findings are significant for reducing animal manure pollution in freeze-thaw season.

秸秆还田是我国一项重要的粮田有机培肥措施,可以增加作物产量、提高土壤有机质含量,具有较好的经济效益和社会效益.该文介绍了秸秆还田技术的应用现状,分析了当前秸秆还田对生态环境效益的影响,以及秸秆还田中存在的问题,为推动秸秆还田技术应用,促进农业可持续发展提供参考.

连续2年在北京市房山区和大兴区4个基地,开展了设施菜田土壤不同盐分胁迫下对黄瓜的株高、茎粗、产量和品质影响的研究.以土壤电导率(EC)为指标,盐分胁迫处理分别为处理1(T1)0.21 dS·m-1、处 理2(T2)0.375 dS·m-1、处理3(T3)0.532 dS·m-1、处理4(T4)0.914 dS·m-1、处理5(T5)1.108 dS·m-1.结果表明:1)黄瓜苗期安全范围是EC值0.25～0.8 dS·m-1,幼苗缓苗快,株高与茎粗达到最佳水平.2)EC值在0.5～0.8 dS·m-1范围时,黄瓜的产量和维生素C含量随着土壤盐分的增加而增加;当EC值大于0.8 dS·m-1时,则随着盐分的增加而下降.硝酸盐变化趋势则刚好相反.黄瓜全生育期安全范围是EC值0.5～0.8 dS·m-1,可确保黄瓜高产与品质提高.3)土壤盐分与黄瓜产量呈负相关(y=-123.76x+164.86,r=0.870,P=0.002).当土壤盐分上升至0.8～0.9 dS·m-1,甚至超过1 dS·m-1时,可能会造成20％～60％的黄瓜减产.

The long-term use of animal manure in agriculture has resulted in estrogen pollution, which poses risks to facility vegetable soils. Owing to the complex soil composition, estrogen may exhibit a variety of behaviors at the water/soil interface. This study demonstrated the role of humic acid (HA) on the 17β-estradiol (E2) adsorption by clay minerals (montmorillonite, kaolinite, and hematite). The interfacial behaviors were investigated using adsorption kinetics and isotherms data. Then, the effects of temperature, pH, and bisphenol A (BPA) on the interactions between humic-mineral complexes and E2 were explored. The adsorption of E2 is an exothermic and spontaneous process, and the addition of HA to minerals significantly promoted their E2 adsorption capacities. Higher pH levels (>10) and the presence of BPA decreased the adsorption capacities of minerals and mineral complexes for E2. Moreover, intercalation, hydrophobic partitioning, π-π interactions and hydrogen bonding could dominate the E2 adsorption onto complexes. These results provided insight into the interfacial behaviors of E2 on the surfaces of humic-mineral complexes and promoted the understanding of the migration and transport of estrogens in soils.