典型旱作农田土壤氧化亚氮排放的氨氧化微生物相对贡献          下载免费PDF全文

杨钰  赵永鉴  宋晓桐  张丽梅  巨晓棠 《土壤学报》2024,61(5)

氨氧化过程对氧化亚氮（N2O）排放具有重要贡献。在不同土壤类型和农田管理下,氨氧化微生物类群对N2O排放的相对贡献组成规律还缺乏系统的研究。本研究选取典型农田耕层土壤（潮土、黑土、砖红壤）,以及有机肥改良的砖红壤剖面土壤,采用选择性抑制法（乙炔和辛炔）研究氨氧化细菌（AOB）、氨氧化古菌和全程硝化菌（AOA+comammox）以及异养硝化菌对土壤硝化潜势、净硝化速率及N2O排放的相对贡献。结果表明,在耕层土壤中,潮土、黑土和砖红壤的pH分别是8.0、6.7和5.7,硝化潜势分别是N 32.5、6.6和4.8 mg?kg-1?d-1,净硝化速率分别是N 7.1、3.0和0.5 mg?kg-1?d-1,7天N2O累积排放量分别是N 38.0、35.4和8.7 μg?kg-1。AOB主导耕层土壤的硝化潜势,对硝化潜势的贡献分别是82%、58%和100%。对于净硝化速率,在潮土和砖红壤中,AOB和AOA+comammox贡献相当（均在30%~40%）,而黑土中由AOB主导（72%）。AOB主导耕层土壤的N2O排放,对N2O排放的贡献分别是72%、92%和58%。在改良的砖红壤剖面土壤中,在0~20 cm、20~40 cm和40~60 cm,pH分别是7.0、5.5和4.9,硝化潜势分别是N 6.6、2.0和1.1 mg?kg-1?d-1,净硝化速率分别是N 4.1、0.9和0.2 mg?kg-1?d-1,N2O排放分别是N 16.3、6.5和2.8 mg?kg-1?d-1。随土壤由深层至表层,硝化潜势、净硝化速率及N2O排放显著提高。AOA+comammox主导表层硝化潜势及净硝化速率的提高（分别贡献63%和54%）,AOB主导N2O排放的增加（贡献54%）。本研究为制定与土壤氨氧化特性及土壤性质相匹配的N2O减排措施提供了新的科学依据。  相似文献   

漏缝地板发酵床对育肥羊养殖气体排放的影响及微生物学机理     

耿仕呈  张伟涛  顾文源  姚惠娇  高志岭  何旭  刘春敬  范玉婧  代宇菲 《农业环境科学学报》2024,43(4):926-936

为明确漏缝地板发酵床对育肥羊养殖过程氨(NH₃)和温室气体排放特征的影响机制,本研究设置地面和漏缝地板发酵床两个试验处理,测定分析了育肥羊养殖过程NH₃、氧化亚氮(N₂O)、二氧化碳(CO₂)和甲烷(CH₄)的排放特征,并采用宏基因组学解析了影响上述气体排放的微生物学机理。试验结果表明,与地面相比,漏缝地板发酵床能够显著降低育肥羊养殖过程的NH₃排放(P<0.05),其NH₃排放速率为21.64～58.92 mg·m^-2·h^-1,NH₃累积排放量为86.36±1.06 g·m^-2,减排率达58.60%。漏缝地板发酵床同样也能显著降低育肥羊养殖过程的CH₄排放速率(P<0.05),其CH₄累积排放量为26.66 g·m^-2,减排率可达64.42%。然而,漏缝地板发酵床会使得...  相似文献   

Abnormal development of genital organs in offspring male mice exposed to finasteride during pregnancy     

FAN Xia  LI Fei  HUANG Huang 《园艺学报》2020,36(2):323-328

AIM: To investigate the effects of finasteride exposure during pregnancy on the development of reproductive organs in offspring male mice. METHODS: CD-1 mice were treated with finasteride from 0 to 17 d after conception. The development of reproductive organs in the offspring male mice were observed by macroscopy, anatomical analysis and histological staining. The spermatogenesis was analyzed by immunofluorescence staining. RESULTS: Macroscopic observation showed that fenasteride exposure during pregnancy resulted in external genital malformations in the offspring male mice, which were manifested as incomplete scrotal fusion and penile malformation. In addition, the anogenital distance was significantly shortened (P<0.01). Histological staining showed that the length of penis at each stage was significantly shortened (P<0.01), the density of seminiferous tubules in testis and mature spermatozoa in seminiferous tubules were significantly decreased (P<0.01), and the luminal space size of seminiferous tubules and interstitial space size of testises were significantly increased (P<0.01). Immunofluorescence staining showed that the densities of Sertoli cells, Leydig cells and spermatogonium in testis were significantly reduced (P<0.01), and the fluorescence intensity of caspase-3 in spermatogenic tubule cells was increased significantly (P<0.01). However, the fluorescence intensity of Ki67 and desert hedgehog (Dhh) was decreased significantly (P<0.01). CONCLUSION: Finasteride exposure during pregnancy results in abnormal development of reproductive organs in offspring male mice and affects spermatogenesis.  相似文献   

辽河平原玉米田不同施肥下的土壤氨挥发特征   总被引：1，自引：0，他引：1  

赵欣周  张世春  李颖  郑益旻  赵洪亮  谢立勇 《中国农业科学》2020,53(18):3741-3751

【目的】通过不同施肥措施对氨气排放贡献的研究,获得辽河平原化肥施用本地化的氨排放因子,为大气环境和生态等领域的相关研究提供参考借鉴。【方法】于2018年5—10月在沈阳农业大学试验基地开展不同施肥措施下的氨气排放的大田试验,以基肥施树脂包衣缓释化肥、拔节期追施尿素为常规施肥方式,设置无氮处理（T0）、常规施肥减半（T1）、常规施肥+生物炭（T2）、常规施肥一次性施入（T3）、常规施肥（T4）5个处理。采用通气法在玉米全生育期内定时收集氨气,利用流动分析仪检测计算氨排放通量,同时测定土壤铵态氮含量。【结果】施基肥后氨挥发速率呈现双峰趋势,各处理分别于施基肥后第1—2天或第5—7天达到氨挥发速率最大值,施基肥后各处理氨挥发速率最大值表现为：常规施肥减半（T1）>常规施肥+生物炭（T2）>常规施肥一次性施入（T3）>常规施肥（T4）>无氮处理（T0）;施追肥后各处理均于第1—2天达到氨挥发速率最大值,追肥后各处理氨挥发速率最大值表现为：常规施肥（T4）>常规施肥+生物炭（T2）>常规施肥减半（T1）>常规施肥一次性施入（T3）>无氮处理（T0）。氨挥发损失累积量表现为常规施肥+生物炭（T2)>常规施肥（T4）>常规施肥一次性施入（T3）>常规施肥减半（T1）>无氮处理（T0）。各时期各处理间的土壤铵态氮含量差异并不显著,但土壤铵态氮含量和同时期土壤氨挥发速率呈现出相似的变化趋势,施追肥后两者的变化趋势比施基肥后更加相似。由于T1、T2、T4追肥期施尿素,尿素释放铵态氮比缓释化肥更加迅速,同时氨挥发也相对较快。整体来看,减少50%施氮量,氨挥发损失累积量只减少20%。各处理间生长季内氨挥发损失累积量差异显著,常规施肥+生物炭（T2）的氨挥发损失累积量最多,在施氮量相同的情况下,加施生物炭氨挥发损失累积量增加22%。全生长季施氮量相同的情况下,一次性施入缓释化肥而不采取尿素追肥的措施比以尿素作为追肥的措施的氨挥发累积量减少12%。【结论】氨挥发随着施氮量增加呈现边际递减效应。生物炭促进了农田氨挥发,玉米秸秆生物炭呈碱性,导致了氨挥发累积量的增加,但其具有孔隙度和比表面积大、吸附效果强的特点,可改良土壤和减少其他温室气体。一次性施入缓释化肥而不采取尿素追肥显著降低了氨挥发。  相似文献   

南方某矿区土壤镉污染及作物健康风险研究   总被引：2，自引：0，他引：2  

张妍  张磊  程红光  孙海旭  崔祥芬 《农业环境科学学报》2020,39(12):2752-2761

为了评估南方某县土壤镉污染情况、量化当地不同作物镉含量并对不同人群健康风险进行评估,从该县3个镇采集135份土壤样本,入户采集128份自产大米样本,种植区采集7份脐橙样本,对其中镉含量进行测定。结果表明,3镇采集土壤样品镉超标率分别为41.67%、28.81%和21.62%,地累积指数计算得到该县68.9%的土壤样本受到不同程度的镉污染,大米镉含量超标率分别为48.57%、34.48%、8.82%。而脐橙果肉样品中镉含量较低,远低于0.05 mg·kg^-1。计算不同作物的危害商数（HQ）可得,食用自产大米的危害商数（HQ）值普遍大于1,风险较高,而食用脐橙果肉产生的健康风险低。种植脐橙具有一定的经济效益,且当地具有脐橙适宜的生长条件,故考虑在重污染区种植脐橙取代种植水稻。  相似文献   

婴幼儿配方乳粉中甲醛含量测定及暴露污染评估     

陈同强  荆辉华  彭国泰  易守福  徐文泱  王亮亮  李凯龙  李灿  向礼 《乳业科学与技术》2021,44(2):15-20

采用气相色谱定量及气相色谱-质谱确证,建立婴幼儿配方乳粉中甲醛含量的测定方法,并对网购45份婴幼儿配方乳粉中甲醛的污染水平进行调查分析与暴露风险评估.通过优化前处理条件,考察方法的线性关系、精密度、准确度、检出限及定量限等指标,采用外标法定量.结果表明:该方法在0～10μg范围内线性良好(r>0.999),方法检出限为...  相似文献   

添加剂对番茄茎秆好氧堆肥发酵过程及氮素损失的影响     

周顺  李洋  张冠智  徐鹏  林爱雨  武永军  杨振超 《中国农业大学学报》2024,(3):79-86

为研究减少在番茄茎秆好氧堆肥过程中氮素损失的途径,提高堆肥品质,以粉碎的番茄茎秆为原料,按物料干重分别加入5%的腐殖酸(T1)、氯化钙(T2)和过磷酸钙(T3),同时以不进行任何添加的堆体作为对照(CK),进行45 d的好氧堆肥试验。结果表明：3种添加剂均可降低堆肥过程中的氮素损失,同时减少了NH₃的挥发量;堆肥结束时,CK、T1、T2和T3处理的氮素损失率分别为18.04%、15.00%、12.65%和14.05%,累计NH₃挥发量为CK(1 648.11 mg/kg)>T1(1 330.35 mg/kg)>T3(995.35 mg/kg)>T2(528.11 mg/kg)。其中,添加氯化钙的处理保氮效果最好,与对照相比,氮素损失率低至12.65%,NH₃挥发量减少67.96%;各处理高温期均≥3 d,发芽指数≥80%,表明堆体已经腐熟,无植物毒性。综上,番茄茎秆好氧堆肥中添加氯化钙,对于减少堆肥过程中的氮素损失较为理想。本研究可为番茄茎秆好氧堆肥保氮工艺优化提供理论依据。  相似文献   

The effect of C/N ratio on bacterial community and water quality in a mussel‐fish integrated system          下载免费PDF全文

Xiafei Zheng  Dongdong Zhang  Jianguang Qin  Yan Wang 《Aquaculture Research》2018,49(4):1699-1708

A 30‐day experiment was conducted to evaluate the effect of C/N ratio on water quality and bacterial community in an integrated system comprising one molluscan species (pearl mussel Hyriopsis cumingii) and two fish species (gibel carp Carassius gibelio and silver carp Hypophthalmichthys molitrix) at five C/N ratios (6, 8, 10, 12 and 14). The mussel and fishes were reared in the experimental tanks (400 L), but gibel carp received formulated feed. Water quality in the experimental tanks was analysed on day 0, 10, 20 and 30, and bacterial community in the water column and sediment was analysed on day 30. Total nitrogen, total phosphorus and total organic carbon accumulated in the tanks over time. Ammonia and nitrite decreased with the increase in C/N ratio. Bacterial community in the water column and sediment changed at the phylum and genus levels with the increase in C/N ratio, and the critical C/N ratio causing a functional shift of bacterial community occurred at 10 in water column and 12 in sediment. The increase in C/N ratio benefited the growth of both potential probiotics and pathogenic bacteria. The high C/N ratio enhanced the bacterial functions of chemoheterotrophy and hydrocarbon degradation, but depressed the functions of nitrification and denitrification in the water column and sediment respectively. This study reveals that the C/N ratio can be used as a tool to manipulate the bacterial community and water quality in the mussel‐fish integrated system.  相似文献   

盐碱地鱼池中病原体小土栖藻的防治   总被引：2，自引：1，他引：2       下载免费PDF全文

杨秀兰  陈金桂  王殿坤  魏运笙  魏玉桐  李文铎 《水产学报》1993,17(4):319-324

我国于70年代中,就开始了对小土栖藻(又名小三毛金藻)的防治研究。大连水产专科学校(1974)报道了小三毛金藻在我国的出现和防治,以后勾维民等(1983)、刘茂春等(1983)、何志辉(1985)、李永函等(1958)、张万达(1990)陆续报道了该害藻的分布和防治。但是,至此小土栖藻的防治技术还带有一定的偶然性和经验性,不能解决生产上的根本问题。本报道,查明了铵氮和小土栖藻消长的关系,指出了非离子氨杀灭小土栖藻的作用和有效含量,提出了一套较完整的预防和治疗方法。使该项研究取得明显的进展和突破。  相似文献   

Effect of dietary protein reduction with lysine and methionnine supplementation on growth performance,body composition and total ammonia nitrogen excretion of juvenile grass carp,Ctenopharyngodon idella     

L. Gan  Y.‐J. Liu  L.‐X. Tian  H.‐J. Yang  Y.‐R. Yue  Y.‐J. Chen  J.‐J. Liang  G.‐Y. Liang 《Aquaculture Nutrition》2012,18(6):589-598

A 63‐day growth trial was undertaken to estimate the effects of supplemented lysine and methionine with different dietary protein levels on growth performance and feed utilization in Grass Carp (Ctenopharyngodon idella). Six plant‐based practical diets were prepared, and 32CP, 30CP and 28CP diets were formulated to contain 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 crude protein without lysine and methionine supplementation. In the supplementary group, lysine and methionine were added to formulate 32AA, 30AA and 28AA diets with 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 dietary crude protein, respectively, according to the whole body amino acid composition of Grass Carp. In the groups without lysine and methionine supplementation, weight gain (WG, %) and specific growth rate (SGR, % day^?1) of the fish fed 32CP diet were significantly higher than that of fish fed 30CP and 28CP diets, but no significant differences were found between 30CP‐ and 28CP‐diet treatments. WG and SGR of the fish fed 32AA and 30AA diets were significantly higher than that of fish fed 28AA diets, and the performance of grass carp was also significantly improved when fed diets with lysine and methionine supplementation (P < 0.05), and the interaction between dietary protein level and amino acid supplementation was noted between WG and SGR (P < 0.05). Feed intake (FI) was significantly increased with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05), but feed conversion ratio (FCR) showed a significant decreasing trend (P < 0.05). Two days after total ammonia nitrogen (TAN) concentration test, the values of TAN discharged by the fish 8 h after feeding were 207.1, 187.5, 170.6, 157.3, 141.3 and 128.9 mg kg^?1 body weight for fish fed 32CP, 32AA, 30CP, 30AA, 28CP and 28AA diets, respectively. TAN excretion by grass carp was reduced in plant‐based practical diets with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05). The results indicated that lysine and methionine supplementation to the plant protein sources‐based practical diets can improve growth performance and feed utilization of grass carp, and the dietary crude protein can be reduced from 320 g kg^?1 to 300 g kg^?1 through balancing amino acids profile. The positive effect was not observed at 280 g kg^?1 crude protein level.  相似文献