双氰胺和3,4-二甲基吡唑磷酸盐对蔬菜种植土壤氨氧化细菌和古菌的影响

硝化抑制剂双氰胺(DCD)和3,4-二甲基吡唑磷酸盐(DMPP)在抑制农业土壤硝化作用和提高氮肥利用率等方面效果显著,为了探讨它们对蔬菜种植土壤氨氧化细菌(AOB)和古菌(AOA)的作用机制,选取40 a以上蔬菜种植土壤,在施加尿素(CK)基础上,分别添加DCD和DMPP进行室内培养,系统监测了土壤中NH_4~+-N、NO_3~--N和硝化势的变化,同时运用荧光定量PCR和高通量测序等技术揭示了AOB和AOA种群丰度和多样性的演替规律.结果表明,相比CK处理,DCD处理和DMPP处理的NH_4~+-N含量升高了213%和675%; NO_3~--N含量降低了13. 3%和37. 2%;硝化势降低了20. 4%和82. 4%;同时,AOB丰度降低了51. 2%和56. 5%; AOA丰度降低了6. 0%和27. 0%.不同抑制剂处理间AOB和AOA的α多样性指数没有显著差异; nork-environmental-samples、unclassified-Nitrosomonadaceae、unclassified-Bactertia和Nitrosospira是AOB序列属水平的主要优势类群; norank-Crenarchaeota、norank-enviromental-samples和Nitrososphaera是AOA序列属水平的主要优势类群,施用DCD和DMPP显著改变了AOB和AOA的群落组成.综上所述,尿素与DCD和DMPP配施显著抑制NH_4~+-N的转化,降低AOB和AOA的种群丰度并改变其群落组成.相比DCD,DMPP对硝化作用的抑制和对AOB和AOA群落的影响更强.     

硝化抑制剂双氰胺对菜地土壤N_2O排放的影响

采用原状土柱试验研究了施用硝化抑制剂双氰胺（DCD）对菜地（小白菜和辣椒）土壤N2O排放的影响.结果表明,施用DCD能显著降低菜地土壤N2O排放通量和排放总量,小白菜未施用DCD时施氮处理土壤N2 O排放总量为0.22 kg.hm-2,施用DCD后则显著减少至0.11 kg.hm-2,相当于减少了49.33%的土壤N2...     

抑制剂对淹水土壤反硝化和氨挥发的影响

通过室内培养试验,设置3个硝化抑制剂双氰胺（DCD）（氮肥用量的2.5%（DCD1）、5.0%（DCD2）、7.5%（DCD3））,3个脲酶抑制剂氢醌（HQ）（氮肥用量的0.1%（HQ1）、0.3%（HQ2）、0.5%（HQ3））和3个硝化抑制剂DCD+脲酶抑制剂HQ联合施用（氮肥用量的2.5%+0.1%（HH1）、5.0%+0.3%（HH2）、7.5%+0.5%（HH3））试验处理,探讨抑制剂联合施用对淹水土壤反硝化和氨挥发过程及其环境因子的影响,并借助通径分析探讨环境因子对反硝化和氨挥发过程的影响程度,探求抑制剂、氮素转化过程及其环境因子之间定量影响关系.结果表明,单独施用硝化抑制剂DCD能显著减少反硝化速率,但是增加氨挥发损失.单独施用脲酶抑制剂HQ能不同程度减少氨挥发损失,但对反硝化作用效果不稳定.而联合施用DCD和HQ,尤其是HH2（5.0%的DCD+0.3%的HQ）联合施用可有效地同时抑制反硝化和氨挥发损失,相比CK,其反硝化和氨挥发速率分别减少31.3%和12.5%.通径分析发现,硝化抑制剂DCD和脲酶抑制HQ主要影响土体NO₃^--N和NH₄⁺-N浓度、上覆水体NH₄⁺-N和DON浓度,从而影响反硝化和氨挥发速率.     

沸石粉和硝化抑制剂投加对污泥堆肥过程中氮素保存和温室气体排放的影响

沸石粉能够通过对氨氮的物理吸附作用,降低堆肥过程中的氮素损失;硝化抑制剂(如3,4-二甲基吡唑磷酸盐,DMPP)能够抑制氨氧化细菌的活性,阻止硝化反应中铵态氮向硝态氮的转化,从而从源头减少反硝化作用而造成的氧化亚氮温室气体的排放.目前国内针对沸石粉和硝化抑制剂(DMPP)作为添加剂对污泥堆肥过程中的保氮作用研究较少,其是否能够实现污泥堆肥过程中温室气体减排也值得深入探讨.本研究以脱水污泥作为研究对象,以蘑菇渣为辅料,设置空白对照、沸石粉和硝化抑制剂(DMPP)添加组,进行21 d的堆肥试验,研究沸石粉和DMPP的添加对污泥堆肥过程的氮素损失和温室气体排放的影响.结果表明,1%的沸石粉添加(湿重)不仅可以减少5%的温室气体排放,而且能够减少2.9%的总氮损失;而DMPP的添加虽然可以减少N_2O的排放,但会显著增加CH_4及NH_3的排放,从而导致温室气体排放和氮素损失的增加.     

氮肥管理措施对黑土玉米田温室气体排放的影响

采用静态箱-气相色谱法研究了不同氮肥管理措施(农民常规施肥、减氮20%、添加硝化抑制剂、施用控释肥)对黑土玉米田温室气体排放的影响.结果表明:黑土玉米田施肥(基肥和追肥)后1~3d出现N2O排放峰,施肥后16d内N2O排放量占生育期总排放量的28.8%~41.9%.减施氮肥20%显著降低土壤N2O排放,生育期内的N2O累积排放量减少了17.6%~46.1%,综合温室效应降低30.7%~67.8%,温室气体排放强度降低29.1%~67.0%.等氮量投入时,添加吡啶抑制剂土壤N2O排放量、综合温室效应和温室气体排放强度最低.玉米拔节~乳熟期出现了较强的土壤CO2排放,黑土玉米田是大气中CH4的一个较弱的“汇”,施氮和添加硝化抑制剂对黑土玉米田CO2排放和CH4吸收没有显著影响.添加硝化抑制剂和施用控释肥不影响玉米产量.在本试验条件下,减氮20%并添加吡啶抑制剂在保证玉米产量的同时, 减排增收效果优于其他施肥措施,适宜在黑土区玉米种植中推广使用.     

氮肥与DCD配施对棚室黄瓜土壤NH3挥发损失及N2O排放的影响

以传统水氮管理为对照,进行了优化水氮管理条件下氮肥与DCD配施对大棚黄瓜土壤氨挥发损失及氧化亚氮排放的影响研究.试验结果表明,与传统水氮管理相比,优化水氮管理减少了氮肥用量及灌水量,但黄瓜产量并没有降低.各水氮处理的NH3挥发速率峰值出现在施肥灌水后的第3d,添加DCD的各优化水氮处理与传统水氮处理相比,土壤氨挥发累积量分别减少55.97%、43.68%、66.47%,4次追肥后W2N2+DCD、W2N3+DCD和W2N4+DCD的氨挥发速率峰值与累积量变化范围较小.不同水氮处理的N2O排放通量的峰值均出现在施肥灌水后的第4d,各追肥时期W2N2+DCD、W2N3+DCD和W2N4+DCD处理,土壤N2O排放通量峰值与N2O累计排放量均显著低于传统水氮处理W1N1,并且3个处理之间不存在显著差异,充分表明优化水氮管理中将氮肥与DCD配施对减少N2O排放起到了显著作用.     

不同施肥处理对东北黑土温室气体排放的短期影响

以东北耕作黑土为对象,在25℃和60%最大持水量(WHC)条件下开展为期7 d的室内培养试验,研究了不同施肥处理对东北黑土温室气体排放的短期影响.结果表明,与不施肥对照处理相比,单施氮肥对土壤呼吸释放的CO_2没有影响,而在施用氮肥的基础上配施有机物料使得CO_2排放量提高了一个数量级,氮肥配施秸秆对CO_2排放的促进效果大于氮肥配施猪粪.短期培养时间内施用氮肥对N_2O排放没有显著影响,硝化作用是对照处理和单施氮肥处理土壤排放N_2O的主要过程.与单施氮肥处理相比,氮肥配施猪粪或秸秆显著促进了反硝化过程,使得N_2O排放量提高了两个数量级,氮肥配施秸秆处理的N_2O排放量显著大于氮肥配施猪粪处理.单施氮肥抑制了CH_4的排放,表现为对CH_4的微量吸收,而氮肥配施猪粪或秸秆则显著促进了CH_4的排放.     

DMPP对热带地区稻田田面水氮素转化的影响

采用水稻盆栽试验,研究高温条件下一次性浅层基施含硝化抑制剂3,4-二甲基吡唑磷酸盐(3,4-dimethylpyrazole phosphate,DMPP)氮肥对热带地区典型红壤稻田田面水氮素转化的影响。结果表明,在水稻移栽后第1~30天中,DMPP氮肥处理田面水铵态氮浓度比普通氮肥处理显著增加23.93%~84.08%,硝态氮和亚硝态氮浓度分别显著降低12.57%~91.23%和7.35%~91.15%,总无机氮浓度显著增加7.79%~65.98%。高温热带地区红壤稻田一次性浅层基施硝化抑制剂DMPP不能减轻氮素向水体迁移的风险,其合理的施用方法有待进一步探讨。     

DMPP对菜地土壤氮素径流损失的影响

利用模拟降雨试验,研究了尿素添加1%新型硝化抑制剂3, 4-二甲基吡唑磷酸盐（3, 4-dimethyl pyrazole phosphate,DMPP）对菜地土壤氮素径流损失的影响.结果表明,添加DMPP抑制剂于尿素, 3次模拟降雨地表径流液中铵态氮含量分别是常规尿素处理的1.42、 2.82和1.95倍,铵态氮径流损失有所增加;使用硝化抑制剂DMPP,与常规尿素相比,3次模拟降雨地表径流液中硝态氮含量分别减少70.2%、 59.7%和52.1%,亚硝态氮含量分别减少98.7%、 90.6%和85.6%,可显著降低硝态氮和亚硝态氮的径流损失,尤其是亚硝态氮的径流损失接近于不施氮处理;常规尿素添加1%的DMPP抑制剂后,可减少39.0%～44.8%的无机氮进入地表水体,明显降低氮素径流迁移损失.使用DMPP抑制剂可减轻氮素向地表水体迁移的风险,具有显著的生态效益.     

秸秆还田配施生物炭对关中平原夏玉米产量和土壤N2O排放的影响

为探明秸秆还田配施生物炭对夏玉米产量和土壤氧化亚氮（N₂O）排放的影响,基于2019~2020年关中平原田间定位试验,利用静态暗箱-气相色谱法监测了土壤N₂O排放通量,综合分析夏玉米产量、土壤N₂O排放和土壤活性氮组分,明确了秸秆还田配施生物炭在培肥土壤、增产减排方面的效应.以秸秆不还田（S₀）为对照,设置秸秆还田（S）和秸秆还田配施生物炭（SB）共3个处理.结果表明,各处理N₂O排放峰值出现在秸秆还田后10 d,秸秆还田30 d后土壤N₂O排放通量处于较低水平,土壤N₂O排放通量与铵态氮（NH₄⁺-N）、无机氮、微生物量氮（MBN）和可溶性有机氮（DON）含量呈显著的正相关关系（P<0.05）.S较S₀显著增加夏玉米产量、N₂O累积排放量、单位产量N₂O累积排放量和土壤总氮（TN）含量,分别为7.4%~13%、65.8%~132.2%、54.6%~103%和27.8%~33%.虽然SB较S提高夏玉米产量（2.5%~3.3%）的趋势不显著（P>0.05）,但是SB较S显著降低N₂O累积排放量和单位产量N₂O累积排放量,分别为24.0%~27.3%和26.4%~29.2%.在土壤N₂O排放通量达到峰值时,SB较S显著降低土壤N₂O排放通量45.1%~69.6%,生物炭能够缓解秸秆还田所诱发的土壤N₂O排放,具有削峰的作用.SB较S显著增加土壤总氮9.1%~12.2%.综合作物产量、N₂O排放和土壤总氮,对夏玉米生产而言,秸秆还田配施生物炭不仅培肥地力,提高夏玉米产量,而且减少单位产量N₂O累积排放量,是可供推广的兼顾作物产量和环境友好的适宜管理措施.     

Effects of lignin on nitrification in soil

The effects of two lignins isolated from black liquor from pulping process on nitrification in soils after addition of urea,(NH4)2SO4 and (NH4)2HPO4 were investigated by incubation at 20 or 30℃ for 7 or 14d.The effects of lignin on nitrous oxide emissions from soil were also detenmined.Results showed that both lignins were more effective for inhibiting nitrification of NH4^ -N as(NH4)2SO4 of(NH4)2HPO4 as compared to urea-N.The effectiveness of lignin on nitrification was markedly affected by different soil type and temperature.Nitrous oxide emissions from soil declined when lignin was used.Urea plus 20 and 50 g/kg lignin reduced N2O emissions by about 83% and 96%,respectively,while(NH4)2HPO4 plus 20 and 50g/kg lignin respectively reduced emissions by 83% and 93%.Because of its low cost and nonhazardous characteristics,lignin has potential value as a fertilizer amendment to improve N fertilizer efficiency.     

3,5-二甲基吡唑磷酸盐硝化抑制作用初探

采用室内培养实验的方法,以不加抑制剂的尿素作为对照,对比研究DMPP及它的同分异构体3,5-二甲基吡唑磷酸盐作为硝化抑制剂对尿素氮在土壤中转化的影响.结果表明,3,5-二甲基吡唑磷酸盐具有一定的硝化抑制作用.在培养期间,施加3,5-二甲基吡唑磷酸盐的土壤中硝态氮的含量一周后始终低于对照,铵态氮的含量一用后始终高于对照.但在培养试验中后期(三周以后),3,5-二甲基吡唑磷酸盐的硝化抑制效果劣于DMPP.3,5-二甲基吡唑磷酸盐能否作为新型硝化抑制剂,还要对它的生理、生态效应等进行进一步的研究.     

Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching

An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4- dimethylpyrazole phosphate （DMPP）, on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca^2＋, Mg^2＋, K^＋, and Na^＋ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.     

Inhibition of nitrification in soil by metal diethyldithiocarbamates

IntroductionNitrificationisaprocessinwhichammoniumformofnitrogenisconvertedintonitrateform .Nitrogenuseefficiencyintermsofplantuptakeisgenerallylowandvariesgreatlyunderdifferentsoilandcroppingconditions.MostfertilizerNappliedtosoilsisintheformofammonium orammoniumproducingcompoundssuchasurea,andisusuallyoxidizedrapidlytonitratebynitrifyingmicroorganismsinsoils.Applicationofnitrogenfertilizersmorethanoptimumlevelsleadstolownitrogenrecoveriesandgreaternitrogenaccumulationinthesoilprofile .Theac…     

Ammonia and greenhouse gas emissions from a subtropical wheat field under different nitrogen fertilization strategies

Minimizing soil ammonia (NH₃) and nitrous oxide (N₂O) emission factors (EFs) has significant implications in regional air quality and greenhouse gas (GHG) emissions besides nitrogen (N) nutrient loss. The aim of this study was to investigate the impacts of different N fertilizer treatments of conventional urea, polymer-coated urea, ammonia sulfate, urease inhibitor (NBPT, N-(n-butyl) thiophosphoric triamide)-treated urea, and nitrification inhibitor (DCD, dicyandiamide)-treated urea on emissions of NH₃ and GHGs from subtropical wheat cultivation. A field study was established in a Cancienne silt loam soil. During growth season, NH₃ emission following N fertilization was characterized using active chamber method whereas GHG emissions of N₂O, carbon dioxide (CO₂), and methane (CH₄) were by passive chamber method. The results showed that coated urea exhibited the largest reduction (49%) in the EF of NH₃-N followed by NBPT-treated urea (39%) and DCD-treated urea (24%) over conventional urea, whereas DCD-treated urea had the greatest suppression on N₂O-N (87%) followed by coated urea (76%) and NBPT-treated urea (69%). Split fertilization of ammonium sulfate-urea significantly lowered both NH₃-N and N₂O-N EF values but split urea treatment had no impact over one-time application of urea. Both NBPT and DCD-treated urea treatments lowered CO₂-C flux but had no effect on CH₄-C flux. Overall, application of coated urea or urea with NPBT or DCD could be used as a mitigation strategy for reducing NH₃ and N₂O emissions in subtropical wheat production in Southern USA.