Effects of various nitrogen fertilizers on emission of nitrous oxide from soils

Summary Field studies of the effects of different N fertilizers on emission of nitrous oxide (N20) from three Iowa soils showed that the N₂O emissions induced by application of 180 kg ha^–1 fertilizer N as anhydrous ammonia greatly exceeded those induced by application of the same amount of fertilizer N as aqueous ammonia or urea. On average, the emission of N₂O-N induced by anhydrous ammonia was more than 13 times that induced by aqueous ammonia or urea and represented 1.2% of the anhydrous ammonia N applied. Experiments with one soil showed that the N₂O emission induced by anhydrous ammonia was more than 17 times that induced by the same amount of N as calcium nitrate. These findings confirm indications from previous work that anhydrous ammonia has a much greater effect on emission of N₂O from soils than do other commonly used N fertilizers and merits special attention in research relating to the potential adverse climatic effect of N fertilization of soils.Laboratory studies of the effect of different amounts of NH₄OH on emission of N₂O from Webster soil showed that the emission of N₂O-N induced by addition of 100 g NH₄OH-N g^–1 soil represented only 0.18% of the N applied, whereas the emissions induced by additions of 500 and 1 000 g NH4OH-N g^–1 soil represented 1.15% and 1.19%, respectively, of the N applied. This suggests that the exceptionally large emissions of N₂O induced by anhydrous ammonia fertilization are due, at least in part, to the fact that the customary method of applying this fertilizer by injection into soil produces highly alkaline soil zones of high ammonium-N concentration that do not occur when urea or aqueous ammonia fertilizers are broadcast and incorporated into soil.     

有机无机肥配施对玉米-豇豆种植系统土壤N2O排放的影响

在等施氮量条件下,比较有机肥与无机肥施用后旱地玉米-豇豆复种系统土壤硝化与反硝化作用、N_2O排放与作物产量的变化,有助于正确认识肥料施用对N_2O排放的影响,为制定大田合理的丰产减排措施提供理论依据。本研究通过田间试验,利用静态箱技术和BaPS气压过程分离技术研究了不同肥料类型处理(无机肥、有机肥、有机无机肥配施)下玉米-豇豆种植系统土壤N_2O排放、硝化与反硝化作用的变化特征。结果表明:1)相对于单施无机肥或有机肥,有机无机肥配施可显著降低土壤硝化作用速率;在玉米生长季,有机无机肥配施处理平均土壤硝化作用速率分别比化肥和有机肥处理显著降低了28.74%和13.96%,豇豆生长季显著降低了24.66%和13.28%。土壤反硝化作用速率在各施肥处理间差异不显著。2)有机无机肥配施显著降低土壤N_2O排放;在玉米生长季,有机无机肥配施处理分别比无机肥处理和有机肥处理显著降低33.44%和32.29%,在豇豆生长季分别显著降低27.00%和15.14%。3)相关分析表明,土壤N_2O排放与硝化作用速率呈极显著相关,而与反硝化作用速率呈不显著相关。4)有机无机配施处理玉米和豇豆产量最高。因此,有机无机肥配施能有效降低玉米-豇豆系统土壤N_2O排放和提高作物产量,是一项丰产低N_2O排放的施肥技术,但长期有机无机肥配施对土壤N_2O排放和作物产量的影响还需要进一步研究。     

Relationships between soil moisture content and nitrous oxide production during nitrification and denitrification

Summary The effect of soil water content [60%–100% water-holding capacity (WHC)] on N₂O production during autotrophic nitrification and denitrification in a loam soil was studied in a laboratory experiment by selectively inhibiting nitrification with a low C₂H₂ concentration (2.1 Pa). Nitrifiers usually produced more N₂O than denitrifiers. During an initial experimental period of 0–6 days the nitrifiers produced more N₂O than the denitrifiers by a factor ranging from 1.4 to 16.5, depending on the water content and length of incubation. The highest N₂O production rate by nitrifiers was observed at 90% WHC, when the soil had become partly anaerobic, as indicated by the high denitrification rate. At 100% WHC there were large gaseous losses from denitrification, while nitrification losses were smaller except for the first period of measurement, when there was still some O₂ remaining in the soil. The use of 10 kPa C₂H₂ to inhibit reduction of N₂O to N₂ stimulated the denitrification process during prolonged incubation over several days; thus the method is unsuitable for long-term studies.     

Gaseous nitrogen losses from fertilized soil during nitrification and denitrification using the acetylene blockage technique

Summary A sandy soil amended with different forms and amounts of fertilizer nitrogen (urea, ammonium sulphate and potassium nitrate) was investigated in model experiments for N₂O emission, which may be evolved during both oxidation of ammonia to nitrate and anaerobic respiration of nitrate. Since C₂H₂ inhibits both nitrification and the reduction of N₂O to N₂ during denitrification, the amount of N₂O evolved in the presence and absence of C₂H₂ represents the nitrogen released through nitrification and denitrification.Results show that amounts of N₂O-N lost from soils incubated anaerobically with 0.1% C₂H₂ and treated with potassium nitrate (23.1 µg N-NO ₃ ^– /g dry soil) exceeded those from soils incubated in the presence of 20% oxygen and treated with even larger amounts of nitrogen as urea and ammonium sulphate. This indicates that nitrogen losses by denitrification may potentially be higher than those occurring through nitrification.     

Background level of nitrous oxide in the atmosphere in relation to flux from soil

According to Broadbent and Clark (3), there are numerous data indicating that denitrification leads to the emission of N₂O together with N₂, whereby loss of N is developed from soils. Nitrous oxide is also released from soils to the atmosphere during the nitrification of ammonium and ammonium-producing fertilizers under aerobic conditions (1). Relatively few attempts have been made to directly measure N₂O evolution under field conditions (6, 7, 10–12), although a number of laboratory studies have been reported. These studies are essential for determining the N balance between additions and losses of soil N.     

不同施肥处理稻田甲烷和氧化亚氮排放特征

采用静态箱－气相色谱法对长期不同施肥处理(NPKS、CK、NPK和NKM)的稻田CH₄和N₂O排放进行了观测。结果表明,稻田CH₄和N₂O排放季节变化规律明显不同,二者排放通量季节变化呈显著负相关(p<0.01)。与单施化肥和CK相比,施用有机肥显著促进CH₄排放,排放量最高的NPKS处理早晚稻田排放量分别是：526.68 kg/hm²和1072.92 kg/hm²。对于N₂O排放,早稻田各处理间差异不显著,NPK处理排放量最大,为1.48 kg/hm²;晚稻田各处理差异极显著(p<0.01),NPKS处理排放量最大,为1.40 kg/hm²。晚稻田CH₄排放通量和10 cm土层温度及土壤pH值相关极显著(p<0.01),并与二者存在显著的指数关系。没发现N₂O排放通量与温度及pH值间存在显著相关。稻田CH₄和N₂O排放受多种因素影响,但对全球变暖的贡献率CH₄远大于N₂O。NPKS处理的增温潜势最大,NPK处理的最小。     

农田土壤N2O生成与排放影响因素及N2O总量估算的研究

综述了国内外农田土壤N2 O生成与排放及其影响因素、N2 O排放测定技术及总量估算等方面的研究进展 ,指出硝化与反硝化过程均可产生N2 O ,而影响硝化、反硝化过程的土壤水分含量、温度、pH、有机碳含量和土壤质地等是影响农田土壤N2 O生成与排放的重要因素。根据我国各地农田土壤N2 O排放通量测定结果及相应模型分析 ,初步估算全国农田土壤N2 O年排放总量为N 398Gg ,约占全球农田土壤排放总量的 1 0 % ,其中旱田N2 O年排放总量为N 31 0Gg ,水田为N 88Gg。     

Processes responsible for the nitrous oxide emission from a Costa Rican Andosol under a coffee agroforestry plantation

We used the inhibitor acetylene (C₂H₂) at partial pressures of 10 Pa and 10 kPa to inhibit autotrophic nitrification and the reduction of nitrous oxide (N₂O) to N₂, respectively. Soils (Andosol) from a Coffea arabica plantation shaded by Inga densiflora in Costa Rica were adjusted to 39, 58, 76 and 87% water-filled pore space (WFPS) and incubated for 6 days in the absence or presence of C₂H₂. Soil respiration, nitrification rates and N₂O emissions by both processes were measured in relation to soil moisture conditions. At all WFPS studied, rates of N₂O and N₂ productions were small (4.8; 14.7; 23 and 239.6 ng N–N₂O g⁻¹ d.w. d⁻¹ at 39, 58, 76 and 87% WFPS, respectively), and despite a low soil pH (4.7), N₂O was mainly produced by nitrification, which was responsible for 85, 91, 84 and 87% of the total N₂O emissions at 39, 58, 76 and 87% WFPS, respectively. At the three smaller values of WFPS, a linear relationship was established between WFPS, soil respiration, nitrification and N₂O released by nitrification; no N₂ was produced by denitrification. At more anaerobic conditions achieved by a WFPS of 87%, a large rate of N₂O production was measured during nitrification, and N₂ production accounted for 84% of the gaseous N fluxes caused by denitrification.     

Nitrate leaching,nitrous oxide emission and N use efficiency of aerobic rice under different N application strategy

A field study was conducted in the sub-humid tropical region of India to examine the effect of different nitrogen (N) management strategies on nitrate leaching, nitrous oxide (N₂O) emission and N use efficiency in aerobic rice. Treatments were: control (no N), 120 kg N ha^?1 applied as prilled urea (PU) in conventional method, 120 kg N ha^?1 applied as neem coated urea (NCU) in conventional method, N applied as PU on the basis of leaf colour chart (LCC) reading, N applied as NCU on the basis of LCC reading, and 120 kg N ha^?1 applied as PU and farm yard manure (FYM) in 1:1 ratio. Results showed that 3.4–16.1 kg NO₃-N ha^?1 was leached below 45 cm depth and 0.61–1.12 kg N₂O-N ha^?1 was emitted from aerobic rice during the growing season. NCU when applied conventionally reduced nitrate-nitrogen (NO₃-N) leaching and N₂O emission by 18.6% and 21.4%, respectively However when applied on the basis of LCC reading NCU reduced NO₃-N leaching by 39.8% as compared to PU applied in conventional method. NCU when applied on the basis of LCC reading synchronized N supply with demand and reduced N loss, which resulted in higher yield and N use efficiency.     

施肥对夏玉米季紫色土N2O排放及反硝化作用的影响

采用原状土柱-乙炔抑制培养法研究了施肥对紫色土玉米生长季土壤N2O排放通量和反硝化作用的影响.结果表明:玉米季施肥显著增加土壤N2O排放和反硝化损失,同时,各施肥处理间N2O排放与反硝化损失量差异显著.猪厩肥、猪厩肥配施氮磷钾肥、氮肥、氮磷钾肥和秸秆配施氮磷钾肥等处理的土壤N,O排放量分别为3.01、2.86、2.51、2.19和1.88 kg hm-2,分别占当季氮肥施用量的1.63％、1.53％、1.30％、1.09％和0.88％,反硝化损失量分别为6.74、6.11、5.23、4.69和4.12 kg hm-2,分别占当季氮肥施用量的3.97％、3.55％、2.97％、2.61％和2.23％,不施肥土壤的N2O排放量和反硝化损失量仅为0.56和0.78 kg hm-2.施肥是紫色土玉米生长前期(2周内)土壤N2O排放和反硝化速率出现高峰的主要驱动因子,土壤铵态氮和硝态氮含量是影响土壤N2O排放、土壤硝化和反硝化作用的限制因子,土壤含水量是重要影响因子,降雨是主要促发因素.土壤N2O排放量与反硝化损失量的比值介于0.45 ～0.72之间,土壤反硝化损失量极显著高于土壤N2O排放量,说明土壤反硝化作用是紫色土玉米生长季氮肥损失的重要途径.     

Relationship between nitrous oxide emission and winter wheat production

A 3-year field study in southeast China was performed to examine the relationship between N₂O emission and winter wheat production. Over the 2002–03, 2003–04 and 2004–05 wheat-cropping seasons, N₂O emissions depended on nitrogen addition, plowing practice, and preceding crop type treatments, and showed a pronounced inter-annual variation. N₂O–N emission factor, the proportion of fertilizer N released as N₂O–N from the wheat field, varied from 1.33% to 2.97%. The relationship between N₂O emission (y) and crop yield (x) was well explained by the function y = 3.773Ln(x) + 1.46. Similarly, the function y = 4.445Ln(x) − 3.52 can be employed to address the relationship between N₂O emission (y) and above ground biomass (x). About 84% and 87% of variation in seasonal N₂O emission were explained by the two functions, while only 66% of the variation was represented by the N input with a linear relationship. The results of this study suggest that seasonal N₂O emission of soil under winter wheat could be better predicted by crop yield and biomass than by N input. Submitted to Biology and Fertility of Soils.     

Decreased nitrous oxide emissions associated with functional microbial genes under bio-organic fertilizer application in vegetable fields

Bio-organic fertilizers enriched with plant growth-promoting microbes(PGPMs)have been widely used in crop fields to promote plant growth and maintain soil microbiome functions.However,their potential effects on N₂O emissions are of increasing concern.In this study,an in situ measurement experiment was conducted to investigate the effect of organic fertilizer containing Trichoderma guizhouense(a plant growth-promoting fungus)on soil N₂O emissions from a greenhouse vegetable field.The following four treatments were used:no fertilizer(control),chemical fertilizer(NPK),organic fertilizer derived from cattle manure(O),and organic fertilizer containing T.guizhouense(O+T,referring to bio-organic fertilizer).The abundances of soil N cycling-related functional genes(amoA)from ammonium-oxidizing bacteria(AOB)and archaea(AOA),as well as nirS,nirK,and nosZ,were simultaneously determined using quantitative PCR(qPCR).Compared to the NPK plot,seasonal total N₂O emissions decreased by 11.7%and 18.7%in the O and O+T plots,respectively,which was attributed to lower NH₄⁺-N content and AOB amoA abundance in the O and O+T plots.The nosZ abundance was significantly greater in the O+T plot,whilst the AOB amoA abundance was significantly lower in the O+T plot than in the O plot.Relative to the organic fertilizer,bio-organic fertilizer application tended to decrease N₂O emissions by 7.9%and enhanced vegetable yield,resulting in a significant decrease in yield-scaled N₂O emissions.Overall,the results of this study suggested that,compared to organic and chemical fertilizers,bio-organic fertilizers containing PGPMs could benefit crop yield and mitigate N₂O emissions in vegetable fields.     

Nitrous oxide emissions from wetland soil amended with inorganic and organic fertilizers

Agricultural soils are a primary source of anthropogenic trace gas emissions, and the subtropics contribute greatly, particularly since 51% of world soils are in these climate zones. A field experiment was carried out in an ephemeral wetland in central Zimbabwe in order to determine the effect of cattle manure (1.36% N) and mineral N fertilizer (ammonium nitrate, 34.5% N) application on N₂O fluxes from soil. Combined applications of 0 kg N fertilizer + 0 Mg cattle manure ha^?1 (control), 100 kg N fertilizer + 15 Mg manure ha^?1 and 200 kg N fertilizer + 30 Mg manure ha^?1 constituted the three treatments arranged in a randomized complete block design with four replications. Tomato and rape crops were grown in rotation over a period of two seasons. Emissions of N₂O were sampled using the static chamber technique. Increasing N fertilizer and manure application rates from low to high rates increased the N₂O fluxes by 37–106%. When low and high rates were applied to the tomato and rape crops, 0.51%, 0.40%, and 0.93%, 0.64% of applied N was lost as N₂O, respectively. This implies that rape production has a greater N₂O emitting potential than the production of tomatoes in wetlands.     

Fluxes and production pathways of nitrous oxide in different types of tropical forest soils in Thailand

Nitrous oxide (N₂O) emissions from the soil surface of five different forest types in Thailand were measured using the closed chamber method. Soil samples were also taken to study the N₂O production pathways. The monthly average emissions (±SD, n?=?12) of N₂O from dry evergreen forest (DEF), hill evergreen forest (HEF), moist evergreen forest (MEF), mixed deciduous forest (MDF) and acacia reforestation (ARF) were 13.0?±?8.2, 5.7?±?7.1, 1.2?±?12.1, 7.3?±?8.5 and 16.7?±?9.2?µg N m^?2 h^?1, respectively. Large seasonal variations in fluxes were observed. Emission was relatively higher during the wet season than during the dry season, indicating that soil moisture and denitrification were probably the main controlling factors. Net N₂O uptake was also observed occasionally. Laboratory studies were conducted to further investigate the influence of moisture and the N₂O production pathways. Production rates at 30% water holding capacity (WHC) were 3.9?±?0.2, 0.5?±?0.06 and 0.87?±?0.01?ng N₂O-nitrogen (N) g-dw^?1day^?1 in DEF, HEF and MEF respectively. At 60% WHC, N₂O production rates in DEF, HEF and MEF soils increased by factors of 68, 9 and 502, respectively. Denitrification was found to be the main N₂O production pathway in these soils except in MEF.     

Mitigating nitrous oxide emissions from a maize-cropping black soil in northeast China by a combination of reducing chemical N fertilizer application and applying manure in autumn

Abstract

Nitrous oxide (N₂O) emissions from agricultural soils, mainly caused by chemical nitrogen (N) fertilizer inputs, are major sources of N₂O in Chinese terrestrial ecosystems. Thus, attempts to reduce N₂O emissions from agricultural soils by optimizing N applications are receiving increasing attention. Further, organic fertilizers are being increasingly used in China to improve crop production/quality and prevent or reduce soil degradation. However, organic and chemical fertilizers are often both applied in spring in northeast China, which promotes N₂O emissions and may be sub-optimal. Therefore, we hypothesized that reducing applications of chemical fertilizer N and applying manure in autumn could be an effective strategy for mitigating N₂O emissions from cropped soils in the region. To test this hypothesis, we established a field trial to investigate the effects of different combinations of chemical N fertilizer applications and animal manure in autumn on both N₂O emissions and maize (Zea mays L.) grain yields in northeast China. The treatments, expressed as NxMy (where Nx and My denote the total amounts of chemical fertilizer nitrogen (N) and manure (M) applied in kg N ha^?1 and m³ M ha^?1, respectively), were N₀M₀, N₂₃₀M₀, N₂₇₀M₁₂, N₂₃₀M₁₅, N₃₂₀M₁₈ in 2010 and N₀M₀, N₂₃₀M₀, N₂₀₀M₁₂, N₂₀₀M₁₅, N₂₈₀M₁₈ in 2011. Measurements of the resulting N₂O emissions showed that pulse fluxes occurred after each chemical N fertilizer application, but not after manure inputs in autumn or during soil-thawing periods in the following spring. Emission factors for the chemical fertilizer N were on average 1.07% (1.00?1.10%) and 1.14% (0.49?1.83%) in 2010 and 2011, respectively. Furthermore, by comparing the nine pairs of fertilization treatments, the relative increase in cumulative nitrous oxide-nitrogen (N₂O-N) emissions was found to be proportional to the relative increase in urea application, but independent of the amount of autumn-applied manure. These findings imply that N₂O emissions from fertilized agricultural soils in northeast China could be mitigated by supplying manure in the autumn and reducing the total amount of chemical N fertilizer applied in the following year. Although no significant difference in maize grain yield was found among the fertilization treatments, the grain yield-scaled N₂O emissions for the treatments with a lower chemical N application (e.g., N₂₃₀M₁₅ and N₂₀₀M₁₅ treatments) were significantly lower than those with a higher chemical N application (e.g., N₃₂₀M₁₈ and N₂₈₀M₁₈ treatments). Meanwhile, under the condition of the same application amount of chemical fertilizer N, the grain yield-scaled N₂O emission decreased with the increase of manure application rate. Thus, the results support the hypothesis that combining reductions in chemical N fertilizer and applying manure in autumn could be an effective strategy for mitigating N₂O emissions from N-fertilized soils in northeast China.     

Effects of the nitrification inhibitor nitrapyrin and tillage practices on yield-scaled nitrous oxide emission from a maize field in Iran

Nitrification inhibitors can effectively decrease nitrification rates and nitrous oxide(N₂O)emission while increasing crop yield under certain conditions.However,there is no information available on the effects of nitrification inhibitors and tillage practices on N₂O emissions from maize cropping in Iran.To study how tillage practices and nitrapyrin(a nitrification inhibitor)affect N₂O emission,a split factorial experiment using a completely randomized block design with three replications was carried out in Northeast Iran,which has a cold semiarid climate.Two main plots were created with conventional tillage and minimum tillage levels,and two nitrogen(N)fertilizer(urea)management systems(with and without nitrapyrin application)were created as subplots.Tillage level did not have any significant effect on soil ammonium(NH₄⁺)and nitrate(NO₃^-)concentrations,cumulative amount and yield-scaled N₂O emission,and aboveground biomass of maize,whereas nitrapyrin application showed significant effect.Nitrapyrin application significantly reduced the cumulative amount of N₂O emission by 41%and 32%in conventional tillage and minimum tillage practices,respectively.A reduction in soil NO₃^-concentration by nitrapyrin was also observed.The average yield-scaled N₂O emission was 13.6 g N₂O-N kg^-1N uptake in both tillage systems without nitrapyrin application and was significantly reduced to 7.9 and 8.2 g N₂O-N kg^-1N uptake upon the application of nitrapyrin in minimum tillage and conventional tillage practices,respectively.Additionally,nitrapyrin application increased maize biomass yield by 4%and 13%in the minimum tillage and conventional tillage systems,respectively.Our results indicate that nitrapyrin has a potential role in reducing N₂O emission from agricultural systems where urea fertilizers are broadcasted,which is common in Iran due to the practice of traditional farming.     

Nitrous oxide production and consumption in serially diluted soil suspensions as related to in situ N2O emission in submerged soils

A simple method for characterizing soil microbial community composition relevant to N₂O production and consumption was proposed. Ten-fold series soil dilution was prepared. Nitrate or N₂O was provided as the sole electron acceptor. Nitrous oxide concentration in the headspace gas across the serially diluted soil suspensions was measured against controls. Results showed that the patterns of N₂O production and consumption across the soil suspensions provided useful information on the microbial community composition relevant to N₂O production and consumption in these soils. An independent method, to that proposed here, was also employed to characterize denitrifier community compositions of the same soils. Data indicated that information on the soil microbial community composition characterized by both methods were compatible or mutually supporting and apparently related to in situ N₂O emissions. Soil samples from manure (applied with animal manure plus chemical fertilizer) plots had higher denitrification rates than the samples from normal fertilizer (applied with chemical fertilizer only) plots. It was concluded that functional characteristics of soil microbial communities relevant to N₂O production and consumption could be characterized at ecological levels and may potentially affect N₂O emissions.     

Seasonal variations of nitrous oxide emission in relation to nitrogen fertilization and energy crop types in sandy soil

Nitrous oxide (N₂O) is a greenhouse gas and agricultural soils are major sources of atmospheric N₂O. Its emissions from soils make up the largest part in the global N₂O budget. Research was carried out at the experimental fields of the Leibniz-Institute of Agricultural Engineering Potsdam-Bornim (ATB). Different types (mineral and wood ash) and levels (0, 75 and 150 kg N ha⁻¹) of fertilization were applied to annual (rape, rye, triticale and hemp) and perennial (poplar and willow) plants every year. N₂O flux measurements were performed 4 times a week by means of gas flux chambers and an automated gas chromatograph between 2003 and 2005. Soil samples were also taken close to the corresponding measuring rings. Soil nitrate and ammonium were measured in soil extracts.N₂O emissions had a peak after N fertilization in spring, after plant harvest in summer and during the freezing–thawing periods in winter. Both fertilization and plant types significantly altered N₂O emission. The maximum N₂O emission rate detected was 1081 μg N₂O m⁻² h⁻¹ in 2004. The mean annual N₂O emissions from the annual plants were more than twofold greater than those of perennial plants (4.3 kg ha⁻¹ vs. 1.9 kg ha⁻¹). During January, N₂O fluxes considerably increased in all treatments due to freezing–thawing cycles. Fertilization together with annual cropping doubled the N₂O emissions compared to perennial crops indicating that N use efficiency was greater for perennial plants. Fertilizer-derived N₂O fluxes constituted about 32% (willow) to 67% (rape/rye) of total soil N₂O flux. Concurrent measurements of soil water content, NO₃ and NH₄ support the conclusion that nitrification is main source of N₂O loss from the study soils. The mean soil NO₃-N values of soils during the study for fertilized soils were 1.6 and 0.9 mg NO₃-N kg⁻¹ for 150 and 75 kg N ha⁻¹ fertilization, respectively. This value reduced to 0.5 mg NO₃-N kg⁻¹ for non-fertilized soils.     

Effect of dairy manure type and supplemental synthetic fertilizer on methane and nitrous oxide emissions from a grassland in Nasu,Japan

Abstract

It is well known that some fungal species are remarkably tolerant of high copper concentration, although copper is toxic to most fungi (Garraway and Evans 1984). Bedford (1936) and Jurkowska (1952) reported that Penicillium and Aspergillus species can grow in liquid media saturated or nearly saturated with copper sulfate. Okamoto and Fuwa (1974) isolated Penicillium ochro-chloron from the laboratory air, and found that the fungus was able to grow in a medium saturated with copper sulfate.