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不同灌溉模式和施氮处理下稻田 CH4 和 N2O 排放 总被引:4,自引:0,他引:4
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用田间试验的方法揭示了不同灌溉模式和施氮处理对双季稻田氧化亚氮(N2O)通量和土壤酶活性的影响。田间试验设3种灌溉模式(常规灌溉CR、“浅湿晒”灌溉TR以及干湿交替灌溉DR)和3种施氮处理(FN1:120 kg hm?2:20%基肥、分蘖肥与穗肥各占40%,FN2:120 kg hm?2:50%基肥、分蘖肥与穗肥各占25%,FN3:90 kg hm?2:50%基肥、分蘖肥与穗肥各占25%),通过定期测定双季稻田N2O通量和土壤酶活性,探讨灌溉模式和施氮处理对稻田N2O排放通量与土壤酶活性的影响,分析了N2O排放通量与土壤酶活性的关系。结果表明:TR和DR模式稻田N2O排放通量较CR模式分别提高92.82%和175.95%,FN3处理稻田N2O排放通量较FN2处理降低39.7%。与CR模式相比,TR模式的土壤脲酶活性、DR模式的土壤羟胺还原酶和亚硝酸还原酶活性升高。双季稻田N2O排放通量与土壤脲酶(晚稻田相关系数0.38;早稻田相关系数0.63)、硝酸还原酶(晚稻田相关系数0.33;早稻田相关系数0.61)和羟胺还原酶(晚稻田相关系数0.63;早稻田相关系数0.73)活性呈显著正相关。可见,不同灌溉模式和施氮处理显著影响土壤脲酶、硝酸还原酶和羟胺还原酶活性和双季稻田N2O排放通量,在生产中应通过稻田水氮管理减少N2O排放,以提高氮肥利用率。 相似文献
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不同形态氮添加对毛竹林土壤N2O排放的影响 总被引:2,自引:1,他引:1
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不同有机肥与化肥配施对作物产量及农田氮肥气态损失的影响 总被引:5,自引:1,他引:4
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为促进氮肥高效利用,实现氮素污染减排,选用膨润土和生物炭作为包膜材料,结合硝化抑制剂制备包膜尿素。设置包膜尿素淋溶模拟试验收集淋溶液,结合静态箱法收集N2O,通过分析NH4+-N,NO3--N淋失量和N2O排放通量对包膜尿素氮素污染减排潜力进行了评估。结果表明:(1)膨润混合土生物炭包膜尿素(F4)NH4+-N淋溶损失率最低,较纯化肥尿素(F1)NH4+-N淋溶损失率降低19.76%。(2)硝化抑制剂型膨润土生物炭包膜尿素(F5)NO3--N淋失率最低,较F1降低16.74%。(3)F5同时具有最优的N2O减排效果,N2O排放量较F1降低77.8%。F5氮素减排效果最优,其减排机制在于一方面硝化抑制剂可以从化学过程控制硝化和反硝化进程,延缓尿素酰胺态氮的水解和铵态氮的硝化,在降低NO3--N淋失的同时可以实现N2O减排。另一方面F5的包膜材料膨润土和生物炭可以通过吸附作用将更多的NH4+-N富集在土壤表层,从而显著降低NH4+-N淋失。综上所述,硝化抑制剂型膨润土生物炭包膜尿素氮素污染减排潜力最优,可使NH4+-N,NO3--N和N2O分别减排15.24%,16.74%和77.8%。 相似文献
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【目的】分析施肥方式及添加脲酶/硝化抑制剂对稻田NH3挥发和N2O排放的影响,基于稻田NH3和N2O减排的效果评价优化施肥措施的可行性。【方法】在太湖地区开展为期两年的稻季田间小区试验,供试脲酶抑制剂为N-丁基硫代磷酰三胺(NBPT),硝化抑制剂为对羟基苯丙酸甲酯(MHPP),用量为施氮量的1%。设置6个处理:1)不施氮肥对照(CK);2)表施尿素N 300 kg/hm2 (当地常规施肥,CN);3)表施尿素N 225 kg/hm2(RNB);4)尿素N 225 kg/hm2,50%表施,50%深施(RND);5)表施尿素N 225 kg/hm2+NBPT+MHPP(RNB+DI);6)尿素N 225 kg/hm2+NBPT+MHPP,50%表施,50%深施(RND+DI)。每次施肥后两周内,用密闭式抽气法监测稻田NH3挥发,在水稻生育期内用静态箱—气相色谱法监测稻田N... 相似文献
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利用室内培养实验,分析燥红壤和砖红壤中分别施加N0(不添加氮素)、N1(氮添加量为100mg·kg−1)、N2(氮添加量为200mg·kg−1)和N3(氮添加量为300mg.kg−1)4个水平氮后对土壤性质及N2O、CO2排放的影响。结果表明:氮肥添加显著降低了土壤pH和有机碳含量。相较于N0,燥红壤N1、N2和N3处理pH和有机碳降幅分别为8%~18%和4%~12%,砖红壤降幅分别为5%~23%和3%~15%;添加氮肥后各处理土壤全氮含量显著增加,燥红壤和砖红壤分别增加15%~54%和13%~52%。氮施入增加了土壤NH4+−N和NO3−−N含量,各处理土壤铵态氮和硝态氮含量均表现为N3>N2>N1>N0。氮添加促进土壤N2O和CO2排放,相较于N0,燥红壤N2O和CO2累积排放量分别增加1176%~2425%和124%~281%,砖红壤分别增加1054%~1887%和138%~256%。施氮量和土壤类型是影响农田土壤N2O和CO2排放的重要因素。土壤N2O和CO2排放与施氮量呈线性显著相关,减少施肥是降低土壤N2O排放最直接和最有效的措施。与砖红壤相比,燥红壤N2O和CO2排放对氮素添加的响应更敏感。 相似文献
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The absorption and transport of Na and Cl from 0.1 mM and 10 mM 22Na labelled NaCl or 36Cl labelled KCl were examined in 15 days old seedlings of 3 cultivars of rice differing in their tolerance to salinity. Furthermore, the effects of 10, 100 and 1000 ppm (N)2S on their uptake were studied. It was found that in general, the salt‐tolerant cultivars BR and PNL‐1 absorbed more Na and translocated a lesser proportion of it to the shoot, compared to the salt‐sensitive IR‐8, from 0.1 mM NaCl. The presence of (N)2S reduced the uptake of Na in all the cultivars. It was also found that the presence of 100 ppm K, KN or NNreduced Na absorption from 0.1 mM NaCl significantly in all the cultivars, and the translocation to shoot in BR‐ Chloride transport from 0.1 mM NaCl was reduced by (N)2S in all the cultivars. The 3 cultivars differed significantly in the rates of absorption and transport of Na and Cl. The results indicate that PNL‐1 which is a cross of IR‐8 X BR, has inherited the salt tolerance trait from BR. Lower rates of Na translocation to the shoot can be used as an index of salt tolerance in rice. 相似文献
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Shin-ichi Yamasaki 《Soil Science and Plant Nutrition》2013,59(2):305-308
Recently conventional chemical analyses were mostly replaced by instrumental analysis. Although results from both methods were examined in details after the samples had been solubilized or extracted by appropriate techniques, the solubilization method was considerably altered so as to be convenient for the following analysis. In atomic absorption spectrophotometry (AAS), for example, fusion technique was mostly inadequate because of the higher salts concentration in the obtained solution. The use of H2SO4 must also be avoided in acid digestion for SO4 2- precipitates with Sr2+ or La3+ which must be added to eliminate interferences in the succeeding procedure. Therefore, it is essential to consider the whole scheme including sample treatments to evaluate the suitability of instrumental analysis. In this experiment, the suitability of the methods which have been employed in our laboratory was examined by analyzing 9 rock standards. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(1):21-26
Abstract The availability of soil Mn to corn in relation to extractability of soil Mn by EDTA, Mg(NO3)2, CH3COONH4, hydroquinone, H3PO4, and NH4H2PO4 as affected by liming was evaluated under field conditions on a single soil type. EDTA, Mg(NO3)2 and CH3COONH4‐extractable Mn were related inversely to available Mn. No useful relationships were found between hydroquinone, H3PO4, and NH4H2PO4‐extractable soil Mn and Mn uptake by sweet corn. 相似文献
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Plant canopy effects on litter accumulation and soil microbial biomass in two temperate forests 总被引:2,自引:0,他引:2
The objective of this study was to determine whether differences in canopy structure and litter composition affect soil characteristics
and microbial activity in oak versus mixed fir-beech stands. Mean litter biomass was greater in mixed fir-beech stands (51.9t
ha−1) compared to oak stands (15.7t ha−1). Canopy leaf area was also significantly larger in mixed stands (1.96m2 m−2) than in oak stands (1.73m2 m−2). Soil organic carbon (C
org) and moisture were greater in mixed fir-beech stands, probably as a result of increased cover. Soil microbial biomass carbon
(C
mic), nitrogen (N
mic), and total soil nitrogen (N
tot) increased slightly in the mixed stand, although this difference was not significant. Overall, mixed stands showed a higher
mean C
org/N
tot ratio (22.73) compared to oak stands (16.39), indicating relatively low rate of carbon mineralization. In addition, the percentage
of organic C present as C
mic in the surface soil decreased from 3.17% in the oak stand to 2.26% in the mixed stand, suggesting that fir-beech litter may
be less suitable as a microbial substrate than oak litter. 相似文献
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J. Juárez-Rodríguez F. Fernández-Luqueño E. Conde V. Reyes-Varela F. Cervantes-Santiago E. Botello-Alvarez 《Journal of plant nutrition》2013,36(4):511-523
Sludge derived from cow manure anaerobically digested to produce biogas (methane; CH4) was applied to maize (Zea mays L.) cultivated in a nutrient-low, alkaline, saline soil with electrolytic conductivity 9.4 dS m?1 and pH 9.3. Carbon dioxide (CO2) emission increased 3.1 times when sludge was applied to soil, 1.6 times when cultivated with maize and 3.5 times in sludge-amended maize cultivated soil compared to the unamended uncultivated soil (1.51 mg C kg?1 soil day?1). Nitrous oxide (N2O) emission from unamended soil was -0.0004 μg nitrogen (N) kg?1 soil day?1 and similar from soil cultivated with maize (0.27 μg N kg?1 soil day?1). Application of sludge increased the N2O emission to 4.59 μg N kg?1 soil day?1, but cultivating this soil reduced it to 2.42 μg N kg?1 soil day?1. It was found that application of anaerobic digested cow manure stimulated maize development in an alkaline saline soil and increased emissions of CO2 and N2O. 相似文献
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It is well known that nitrogen fixation is mainly dependent upon the combination between rhizobial strain and host plant species, though it is also affected by the environmental condition. The site of association between the host and rhizobia is the root nodule. It is, therefore, quite natural that special attention has hitherto been focused on it. A typical symbiotic relationship is going on in effective nodule, while a parasitic relationship prevails in ineffective one. Between such types of nodules there must be some differences with respect to the inner structure as well as the metabolism in them. Experiments were made to compare the morphological change of rhizobia, the amount and distribution of starch, the kinds of free amino acids in effective nodule with those in ineffective one. To obtain materials, soybean, pea, red clover, and genge (Astragalus sinicus L.) Were used with their own effective and ineffective strains of rhizobia, respectively. 相似文献
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We examined the potential of a subsoil to denitrify nitrate under optimal anaerobic conditions in a laboratory-based incubation when supplied with a range of C substrates of increasing recalcitrance. Both topsoil and its associated subsoil were supplied with nitrate and either glucose, starch or cellulose. Microbial respiration and the evolution of N2O and N2 were measured. The subsoil supported low amounts of microbial activity and responded only to the glucose treatment; with less than one-fifth of the N2O production measured in the top soil. Overall, our findings demonstrated that the denitrification potential of this particular subsoil is relatively low and that only simple carbohydrates could be utilised readily by the resident microorganisms. 相似文献
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Tomoaki Morishita Kyotaro Noguchi Yongwon Kim Yojiro Matsuura 《Soil Science and Plant Nutrition》2013,59(1):98-105
AbstractForest fires can change the greenhouse gase (GHG) flux of borea forest soils. We measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes with different burn histories in black spruce (Picea mariana) stands in interior Alaska. The control forest (CF) burned in 1920; partially burned (PB) in 1999; and severely burned (SB1 and SB2) in 2004. The thickness of the organic layer was 22 ± 6 cm at CF, 28 ± 10 cm at PB, 12 ± 6 cm at SB1 and 4 ± 2 cm at SB2. The mean soil temperature during CO2 flux measurement was 8.9 ± 3.1, 6.4 ± 2.1, 5.9 ± 3.4 and 5.0 ± 2.4°C at SB2, SB1, PB and CF, respectively, and differed significantly among the sites (P < 0.01). The mean CO2 flux was highest at PB (128 ± 85 mg CO2-C m?2 h?1) and lowest at SB1 (47 ± 19 mg CO2-C m?2 h?1) (P < 0.01), and within each site it was positively correlated with soil temperature (P < 0.01). The CO2 flux at SB2 was lower than that at CF when the soil temperature was high. We attributed the low CO2 flux at SB1 and SB2 to low root respiration and organic matter decomposition rates due to the 2004 fire. The CH4 uptake rate was highest at SB1 [–91 ± 21 μg CH4-C m?2 h?1] (P < 0.01) and positively correlated with soil temperature (P < 0.01) but not soil moisture. The CH4 uptake rate increased with increasing soil temperature because methanotroph activity increased. The N2O flux was highest [3.6 ± 4.7 μg N2O-N m?2 h?1] at PB (P < 0.01). Our findings suggest that the soil temperature and moisture are important factors of GHG dynamics in forest soils with different fire history. 相似文献