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Noise, as an unavoidable stress (pressure) source in the modern life, affects animals in many ways, both behaviorally and physiologically. Behavioral changes may be driven by changes in hormone secretion in animals. When animals face with noise stress, the neuroendocrine systems, mainly the hypothalamic-pituitary-adrenal (HPA) axis, are activated, which promotes the secretion and release of stress hormones, and then leads to a series of behavioral changes. The behavioral changes can be easily observed, but the changes in physiological indicators such as hormone levels need to be accurately measured. Currently, many studies have measured the variations of stress hormone levels in animals under different noise conditions. Taking glucocorticoid as an example, this paper summarizes the different measurement methods of stress hormones, especially the non-invasive measurement methods, and compares the advantages and shortcomings of them. It provides a variety of measurement choices for the study of related issues, and also helps us to further understand the sources of animal stress, in order to provide a better habitat for animals.
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Sistema Hipotálamo-Hipofisário , Ruído , Sistema Hipófise-Suprarrenal , Estresse Fisiológico , Animais , Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Estresse Fisiológico/fisiologia , Glucocorticoides/metabolismo , Estresse Psicológico/fisiopatologiaRESUMO
Reduced ambient temperature has a damaging effect on mammalian myocardium. Huddling as a cooperative behavior has evolved in social mammals as a strategy to maximize adaptation to environmental cooling. Here, we studied the effects of huddling behavior on mitochondrial morphology, number, and function in the myocardia of Brandt's voles (Lasiopodomys brandtii) under cool environmental temperatures (15 °C). Results showed (1) mitochondrial swelling and cristae disruption in the cool huddling group (CH) and cool separated group (CS). Compared to the control group (CON, 22 °C), damaged mitochondria in the cool huddling and separated groups reached >90%; however, total number of mitochondria in the CH group was similar to that in the CON group. (2) ATP synthase activity was lowest in the CS group, whereas citrate synthetase activity was maintained among the three treatment groups. (3) Bax/bcl2 protein expression in the CH and CS groups was higher than that in the CON group, whereas DNA fragmentation, nuclear number, and caspase3 activity showed no significant differences among the three groups. (4) The protein expression levels of dynamin-related protein1 and mitochondrial fission factor were highest in the CH group. (5) Both protein expression of PINK1 and phosphorylation ratio of Parkin showed the pattern CS > CH > CON. (6) Total number of mitochondria was higher in males than in females. In general, the increased mitochondrial fission level observed in huddling voles partially counteracted the decrease in myocardial mitochondria caused by the increase in autophagy.
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Arvicolinae/fisiologia , Temperatura Baixa , Mitocôndrias Cardíacas/ultraestrutura , Adaptação Fisiológica/fisiologia , Animais , Apoptose , Autofagia , Comportamento Animal , Peso Corporal , Caspase 3/metabolismo , Núcleo Celular/metabolismo , Feminino , Masculino , Mitocôndrias/metabolismo , Comportamento Social , Proteína X Associada a bcl-2/metabolismoRESUMO
Organic fertilizer substitution has been promoted as a weight loss, efficient, and diversified fertilizer substitution technology in agricultural production. However, there is a lack of comprehensive assessment of the impact of organic fertilizers on N2O and NO emissions from orchards. In this study, N2O and NO emissions from peach orchards were observed annually using static dark box-gas chromatography to compare the effects of chemical fertilizer application alone and partial replacement of chemical fertilizer treatment on NO emissions from peach orchards. The results showed that the partial replacement of chemical fertilizers with organic fertilizers reduced the total N2O and NO emissions from peach orchards by 15.0 % and 9.4 %, respectively. The N2O and NO emission factors were reduced by 21.3 % and 21.1 %. The mineral N content of the soil in the organic fertilizer treatment was lower than that in the chemical fertilizer treatment alone. The organic fertilizer treatment increased the contribution of AOA to nitrification and decreased the contribution of AOB, thus reducing N2O and NO from nitrification. In addition, the results of the dual isotope mixing model[δ18O(N2O/H2O) vs. δ15NSP] indicated that the bacterial denitrification/nitrifying bacterial denitrification (bD/nD) process served as the primary pathway for N2O emissions in peach orchards. Partial substitution with organic fertilizers enhanced soil denitrification, resulting in larger reductions in the amounts of N2O and NO. Therefore, partial substitution of organic fertilizer is a viable measure to mitigate nitrogen oxide emissions from orchards and to achieve green and low-carbon development in agriculture.
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Background: The relationship between serum antinuclear antibody (ANA) and rheumatoid arthritis (RA) remains unknown. Therefore, we aimed to evaluate whether serum ANA was associated with an increased risk of RA in a case-control study. Methods: Patients with rheumatoid arthritis hospitalized at Shandong Provincial Hospital from January 2018 to December 2022 were recruited as the case group, and patients with other types of arthritis and healthy people at the same time were taken as the control group. Antinuclear antibody (ANA) was detected by indirect immunofluorescence assays. Propensity score matching was employed to construct a cohort of patients exhibiting comparable baseline characteristics. The relationship between serum ANA and the risk of rheumatoid arthritis was analyzed by logistic regression analysis. Results: A total of 1,175 patients with RA and 1,662 control subjects were included in this study. After adjusting for potential confounding factors in the propensity-score matched cohort, the risk of RA gradually increased with rising of ANA titers. When ANA titers were divided into three groups (1:100, 1:320, and 1:1,000), the OR (95% CI) for ANA titers from low to high was 3.95 (3.01, 5.18), 16.63 (9.44, 29.30), and 17.34 (9.53, 31.54), respectively, compared to those when ANA was negative. The ANA patterns closely related to the occurrence of RA include nuclear homogeneous, nuclear speckled, and cytoplasmic speckled. Among them, the positive rate of nuclear homogeneous was the highest, which accounted for 42.64%. The OR (95% CI) of ANA patterns including nuclear homogeneous, nuclear speckled, and cytoplasmic speckled was 16.81 (11.46, 24.65), 3.40 (2.49, 4.63), and 3.09 (1.77, 5.40), respectively. Conclusion: There was a curve relation between ANA titer and RA, and the higher the ANA titer, the higher the probability of RA. However, there was no statistical difference in probability of RA for 1:320 versus 1:1,000 ANA titers. The most important kind of ANA pattern in the blood of RA patients was nuclear homogeneous. These findings suggest that ANA may be a novel risk marker for RA.
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Anticorpos Antinucleares , Artrite Reumatoide , Humanos , Artrite Reumatoide/sangue , Artrite Reumatoide/imunologia , Artrite Reumatoide/diagnóstico , Anticorpos Antinucleares/sangue , Anticorpos Antinucleares/imunologia , Masculino , Feminino , Pessoa de Meia-Idade , Estudos de Casos e Controles , Adulto , Idoso , Biomarcadores/sangue , Fatores de RiscoRESUMO
Freshwater aquaculture ponds collectively cover a large area in southeast China. They are an important anthropogenic source of CH4 emissions, however current knowledge of CH4 emissions from aquaculture ponds is limited. During September 2017 and August 2018, two independent sampling campaigns of CH4 flux measurements over annual cycles were carried out in a fish-aquaculture pond in southeast China using a floating chamber and diffusion model methods for comparison. The purpose of this study is to investigate the variation of CH4 fluxes obtained from the fish-aquaculture pond, analyze the emission mechanisms, and amplify the CH4 emissions inventory. The diffusion model method can further quantify the contribution of diffusion transmission to CH4 emissions. The seasonal variations of CH4 fluxes measured by the two methods were similar, with higher CH4 fluxes appearing in summer and fall and lower CH4 fluxes appearing in spring and winter. CH4 fluxes measured by the floating chamber method and diffusion model method ranged from 0.14-3.13 mg·(m2·h)-1 and 0.04-1.41 mg·(m2·h)-1, respectively, and the respective average values were (0.86±0.30) mg·(m2·h)-1and (0.45±0.08) mg·(m2·h)-1. The CH4 fluxes were positively related to water temperature, dissolved organic carbon (DOC) and chemical oxygen demand (COD), but negatively related to the water dissolved oxygen (DO) concentration in the fish-aquaculture pond. CH4 fluxes calculated by diffusion model methods were 45% lower than those determined by the floating chamber methods over annual cycles. The result suggested that the floating chamber method is more suitable than the diffusion model method for measurements of CH4 fluxes in freshwater aquaculture ecosystems.
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Aquicultura , Monitoramento Ambiental/métodos , Metano/análise , Lagoas , Animais , China , Estações do AnoRESUMO
Hydrogen-rich water (HRW) has been widely used in research on plant resistance to Cd. However, the underlying molecular mechanism of HRW in ameliorating cadmium stress in vegetables is largely unknown. In this study, the RNA-sequencing analyses were used to characterize the role of HRW in the alleviation of Cd toxicity in Chinese cabbage seedlings. Based on the obtained results, two genes encoding metal ionic transporters, BcIRT1 and BcZIP2 were ultimately selected out. Then, a systematic validation of the metal ion transport function of these two ZIP-encoding genes of pak choi were performed via a yeast transformation system. The results showed that BcIRT1 and BcZIP2 increased the sensitivity of different yeast mutant strains to relative metal ionic stresses and facilitated the accumulation of metal ions (Cd2+, Mn2+, Zn2+, and Fe2+) in yeast; thus, it suggests that BcIRT1 and BcZIP2 probably have the ability to transport Cd2+, Mn2+, Zn2+ and Fe2+ in pak choi. The time-course and concentration-dependent expression profiles of BcIRT1 and BcZIP2 showed that as time with HRW increased, the effectiveness of the repression on the expression of BcIRT1 and BcZIP2 increased, and as the seedlings were exposed to increased Cd concentrations, the inhibition of BcIRT1 and BcZIP2 by HRW was also increased. Over all, these findings provide new insights into the genome-wide transcriptome profiles in pak choi and show that HRW reduced Cd uptake probably through inhibiting the expression of transporters related to Cd absorption, BcIRT1 and BcZIP2.
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Brassica/química , Cádmio/química , Proteínas de Membrana Transportadoras/química , Água/química , Transporte Biológico , Perfilação da Expressão Gênica , Água/análiseRESUMO
BACKGROUND: Observing serum IgG concentration on the distribution of serum, blood cells, and separation gel after centrifugation in different separation gel vacuum tubes. METHODS: 3 mL venous blood was collected in each of two separation gel procoagulant vacuum tubes: BD Vacutainer SST II(3.5ml, 75×13 mm) and BD Vacutainer SST(5ml, 100×13 mm). After complete solidifaction, both tubes were centrifuged at 2000g for 10 minutes. The distribution of serum, blood cells, and separation gel in the vacuum tube was observed. The immunoglobulin concentration was detected using the special protein analyzer Siemens BNII. RESULTS: 1. In the group of BD Vacutainer SST II where the IgG concentration exceeded 50g/L but less than 122g/L: The serum was located below the separation gel and was distributed in three layers: separation gel, serum, and blood cells. 2. In the group of BD Vacutainer SST where the IgG concentration exceeded 50g/L but less than 122g/L: The serum was located above the separating gel, and was distributed in three layers: serum, separation gel, and blood cells. 3. Increases in IgA and IgM serum concentration did not cause the separation gel inversion. CONCLUSIONS: Increases in serum IgG were positively correlated with the concentration of total protein. The rising of serum IgG caused the floating of separation gel after centrifugation. The BD Vacutainer SST was more suitable for clinical blood sample collection.
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Proteínas Sanguíneas/metabolismo , Coleta de Amostras Sanguíneas/instrumentação , Coleta de Amostras Sanguíneas/métodos , Imunoglobulina G/sangue , Mieloma Múltiplo/sangue , Centrifugação , Feminino , Humanos , Masculino , Estudos Retrospectivos , VácuoRESUMO
BACKGROUND: Kawasaki disease is treated by immunoglobulin therapy, which has adverse side effects like renal damage. AIMS: The aim of the present study was to explore the effectiveness of triptolide, a compound derived from threewingnut that has anti-inflammatory effects, on the treatment of Kawasaki disease in a mouse model. STUDY DESIGN: Animal experiment. METHODS: A mouse model of Kawasaki disease was established through exposure to Candida albicans by intraperitoneal injection. Exposed mice were then randomly divided into several groups (each n=15): model group (saline-treated), low- or high-dose triptolide groups (0.2 mg/kg or 0.4 mg/kg, respectively), and IVIG (high-dose immunoglobulin) group (1 g/kg body weight). Unexposed mice served as an additional control group. Nine weeks from the initial exposure, mice were euthanised and coronary tissues and blood samples were harvested. The rate of apoptosis was detected by TUNEL, and ICAM-1 expression was detected by immunohistochemistry in coronary endothelial cells. Serum TNF-α levels were detected by ELISA. RESULTS: Compared to mice in the (unexposed) control group, apoptosis of endothelial cells, ICAM-1 expression, and serum TNF-α levels were significantly increased in all exposed mice (p<0.05), confirming the presence of disease. However, treatment with triptolide or IVIG significantly lowered these measures compared to untreated exposed mice (model group; p<0.05). CONCLUSIONS: Triptolide treatment reduces markers of coronary endothelial inflammation in a mouse model of Kawasaki disease, similar to IVIG treatment, and therefore may be a useful alternative therapy for this disease.
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OBJECTIVE: To provide the basis for clinical acquired immunodeficiency syndrome (AIDS) surveillance and to avoid cross infection in hospital, we study the infection status of AIDS in Shandong province. METHODS: The fourth-generated Akzo's ELISA kit and the fourth generated Immunoluminometric detection reagent were used for HIV antibody screening for 399 303 cases of both inpatients and outpatients from Jan. 2003 to Dec. 2011. Beijing WanTai ELISA kit and Se-marked rapid detection reagent were used for re-detection, and the positive samples were sent to the local CDC for confirming test by Western Blot. RESULTS: The HIV-1 antibody detection results of 129 (0. 3230 per thousand) patients were confirmed to be positive, including 54 (0. 1352 per thousand) cases of outpatients and 75 (0. 1878 per thousand) cases of inpatients. HIV infection rates in outpatients from 2003 to 2011 were 0.050 per thousand, 0.030 per thousand, 0.111 per thousand, 0.120 per thousand, 0.124 per thousand, 0.113 per thousand, 0.148 per thousand, 0.201 per thousand, 0.2152 per thousand; and that in inpatients were 0. 150 per thousand, 0.089 per thousand, 0.138 per thousand, 0. 144 per thousand, 0. 104 per thousand, 0. 132 per thousand, 0. 197 per thousand, 0. 329 per thousand, 0. 313 per thousand respectively. Among these inpatients, there were 61 cases of medical patients and 14 cases of surgical patients, and most were youths and farmers. CONCLUSIONS: HIV infection rate was increasing year by year. Most inpatients whose HIV-1 antibody was positive were in the phase of AIDS. Therefore, it's very necessary to execute routine testing for inpatients and outpatients who need special examination for early diagnosis of HIV infection
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Síndrome da Imunodeficiência Adquirida/epidemiologia , Anticorpos Anti-HIV/análise , Infecções por HIV/epidemiologia , Síndrome da Imunodeficiência Adquirida/imunologia , Síndrome da Imunodeficiência Adquirida/virologia , Adolescente , Adulto , Idoso , China/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
With a view to improving treatment response and the quality of life of cancer patients, this study investigated the clinical efficacy of combining lentinan, a flavonoid compound with antitumor abilities, with traditional chemotherapy in individuals with esophageal carcinoma (EC), with a particular focus on its effect on immune function. A total of 50 patients undergoing treatment for EC were evenly divided into two groups: control and experimental. Patients in the control group were treated with the chemotherapeutic agent tegafur (1,000 mg/day for 5 days); patients in the experimental group were treated with the same dosage of tegafur combined with 1 mg lentinan diluted in 250 ml normal saline. Patients were monitored for their general condition, symptoms and signs, quality of life and clinical efficacy (remission vs. progression). Additionally, the effects of lentinan on immune function were assessed through analysis of serum levels of pro-inflammatory and anti-inflammatory cytokines using enzyme-linked immunosorbent assay (ELISA) prior to and following the first and second course of treatment. The results of the scores showed that the general condition (Karnofsky performance scale; KPS), the symptoms and signs (Zubrod-ECOG-WHO score; ZPS) and the quality of life (QOL scale) of the patients following the first and second course of treatment were better in both groups compared to the scores prior to treatment; however, patients in the experimental group exhibited significantly greater improvement than those in the control group (P<0.05). Clinical efficacy was not significantly different between the two groups after 1 course of treatment, but after 2 courses of treatment, clinical efficacy was significantly greater in the experimental group than in the control group (P<0.05). Additionally, serum levels of IL-2, IL-6 and IL-12 increased, while levels of IL-4, IL-5 and IL-10 decreased, in patients of both groups after 2 courses of treatment (P<0.05). These changes occurred to a greater extent in the experimental group than in the control group (P<0.05). In conclusion, the addition of lentinan to the chemotherapy regimen improves the general condition, symptoms and signs, and quality of life of patients with EC. In particular, the patient's immune function may be enhanced by the combined treatment. The generalized application of lentinan is, therefore, recommended in the clinic.
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Antineoplásicos/uso terapêutico , Carcinoma/tratamento farmacológico , Neoplasias Esofágicas/tratamento farmacológico , Lentinano/uso terapêutico , Adulto , Idoso , Carcinoma/imunologia , Citocinas/metabolismo , Quimioterapia Combinada , Neoplasias Esofágicas/imunologia , Feminino , Humanos , Interleucina-10/sangue , Interleucina-12/sangue , Interleucina-2/sangue , Interleucina-4/sangue , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Tegafur/uso terapêutico , Resultado do TratamentoRESUMO
Various water management regimes, such as continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F), and flooding-midseason drainage-reflooding-moist intermittent irrigation but without water logging (F-D-F-M), are currently practiced in paddy rice production in China. These water regimes have incurred a sensitive change in direct N2O emission from rice paddy fields. In order to establish statistical models quantifying the country-specific emission factor and background emission of N2O in paddy fields during the rice growing season, we compiled and statistically analyzed field data on 71 N2O measurements from 17 field studies that were published in peer-reviewed Chinese and English journals. For each field study, we documented the seasonal N2O emission, the type and amount of organic amendment and fertilizer nitrogen application, the water management regime, the drainage duration, the field location and cropping season. Seasonal total N2O was, on average, equivalent to 0.02% of the nitrogen applied in the continuous flooding rice paddies. Under the water regime of F-D-F or the F-D-F-M, seasonal N2O emissions increased with N fertilizer applied in rice paddies. Applying an Ordinary Least Square (OLS) linear regression model resulted in an emission factor of 0.42% for N2O, and in unpronounced background N2 O emission under the water regime of F-D-F. Under the F-D-F-M water regime, N2O emission factor and N2O-N background emission were estimated to be 0.73% and 0.79 kg x hm(-2) during the paddy rice growing season, respectively. After considering three different water regimes in rice paddies in China, the emission factor of N for N2O and N2O-N background emission averaged 0.54% and 0.43 kg x hm(-2). The results of this study suggest that paddy rice relative to upland crop production could have contributed to mitigating N2O emissions from agriculture in China. The emission factor of N for N2O and its background emissions can be directly adopted to develop national inventory of N2O emissions from paddy fields during the rice growing season in China.
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Agricultura/métodos , Poluentes Atmosféricos/análise , Modelos Lineares , Óxido Nitroso/análise , Oryza/crescimento & desenvolvimento , China , Monitoramento Ambiental , Fertilizantes/análise , Inundações , Nitrogênio/análise , Estações do Ano , Água/análiseRESUMO
In order to examine the effects of management regime, such as nitrogen application and plowing method, on soil respiration from farmland, the static opaque chamber-gas chromatograph method was used to measure soil CO2 fluxes in situ. The field measurement was carried out for 5 growing seasons, which were the 2002-2003 wheat, 2003 maize and soybean, 2003-2004 wheat, 2004 maize and 2004-2005 wheat seasons. Our results showed that soil respiration increased in fertilizer-applied treatments compared with no fertilizer treatment after 3 times of fertilizer application on 9 November 2002, 14 February and 26 March 2003. And the most obvious increase appeared following the third fertilizer application. No significant difference in soil respiration was found among several fertilizer application treatments. The effect of plowing depth on soil respiration was contingent on preceding cropping practice. Over the 2003-2004 wheat-growing seasons (its preceding cropping practice was rice paddy), mean soil respiration rates were not significant different (p > 0.05) between no plowing treatment and shallow plowing treatment. The shallow plowing treatment CT2 led to higher soil CO2 losses compared with no plowing treatment of NT2 in the 2004 maize-growing season, however, the significant higher (p < 0.05) soil respiration rates occurred with no plowing treatment of NT3 in the following 2004-2005 wheat-growing season. Intensive plowing (25 cm depth), compared with no plowing practice (NT4), increased soil respiration significantly during the 2004-2005 wheat-growing season. Regression analysis showed that the exponential function could be employed to fit the relationship between soil respiration and temperature. The exponential relationship yielded the Q10 values which were varied from 1.26 to 3.60, with a mean value of 2.08. To evaluate the effect of temperature on soil respiration, the CO2 emission fluxes were normalized for each treatment and each crop growing season. Plotting the normalized soil respiration against the temperature, the exponential relationship between these two parameters becomes obvious. The temperature coefficient Q10 was then evaluated as 1.66 according to the exponential relationship. Further investigation indicated that soil respiration could be well simulated by an empirical model in which the effects of both soil temperature and moisture on soil respiration were considered. This model described 54% variances of the measured 463 soil respiration rates, with a R2 of 0.54 and a p value less than 0.0001.
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Dióxido de Carbono/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Ecossistema , Fertilizantes , Solo/análise , Dióxido de Carbono/análise , Respiração Celular , Nitrogênio/análiseRESUMO
The models on direct N2O emissions from rice paddies under different water regimes developed by the authors were validated against field measurements in China reported in 2005-2007 and in other regions. In flooding rice paddies (F), N2O emission predicted by the model was consistent with previous reports in other regions. Under the water regime of flooding-midseason drainage-reflooding (F-D-F), the model developed in this study was comparable to that established by using worldwide database. The models also well fitted N2O emissions from rice paddies under the water regime of flooding-midseason drainage-reflooding-moisture but without waterlogging (F-D-F-M) in China. Consistency of rice production data derived from the database of this study with those reported in previous studies suggests that the model input data of rice production had high reliability. The input data showed that water management and nitrogen input regimes have greatly changed in rice paddies since the 1950s. During the 1950s-1970s, about 20%-25% of the rice paddy was continuous water logging, and 75%-80% under the water regime of F-D-F. Since the 1980s, about 12%-16%, 77% and 7%-12% of paddy fields were under the water regimes of F, F-D-F and F-D-F-M, respectively. Total N input during the rice growing season averaged 87.49 kg x hm(-2) in the 1950s and 224.64 kg x hm(-2) in the 1990s. Chemical N input during the rice growing season has increased from 37.4 kg x hm(-2) in the 1950s to 198.8 kg x hm(-2) in the 1990s, accounting for 43% and 88% of the seasonal total N inputs, respectively. Manure N input was applied at stable rate, ranging from 45.2 kg x hm(-2) to 48.2 kg x hm(-2) during the 1950s-1970s, but thereafter it decreased over time. The contribution of manure N to total N inputs has decreased from 52% in the 1950s to 9% in the 1990s. Crop residue N retained during the rice growing season has increased from 4.9 kg x hm(-2) in the 1950s to 6.3 kg x hm(-2) in the 1980s. A high spatial variation of nitrogen inputs during the rice growing season was found in the 1950s-1970s, while it was not pronounced in the 1980s-1990s. Overall, the results of this study suggest that the models could be used to quantify direct N2O emissions from rice paddies under various water regimes in China.
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Agricultura/métodos , Poluentes Atmosféricos/análise , Modelos Teóricos , Óxido Nitroso/análise , Oryza/crescimento & desenvolvimento , China , Monitoramento Ambiental , Fertilizantes/análise , Inundações , Nitrogênio/análise , Oryza/metabolismo , Estações do Ano , Solo/análiseRESUMO
Based on statistical analysis of field N2O measurements in rice paddies in China, the models on direct N2O emissions under different water regimes were established. After successes in model validation and input data verification, the models were used to quantify changes in direct N2O emissions from paddy fields during the rice growing season in mainland China between the 1950s and the 1990s. Due to increases in rice planting area and nitrogen input and changes in water regime, the models predicted that seasonal N2O-N emissions from rice paddies have increased from 9.55 Gg each year in the 1950s to 32.26 Gg N2O-N in the 1990s, which was accompanied by the increase in rice yield over the period 1950s-1990s. During the period 1950s-1990s, seasonal N2O-N emissions from rice paddies have increased, on average, at a rate of 6.74 Gg per decade. Seasonal N2O fluxes in rice paddies were estimated to be 0.32 kg x hm(-2) in the 1950s and 1.00 kg x hm(-2) in the 1990s, which accounted for 0.37% and 0.46% of the seasonal total N inputs, respectively. The uncertainties in N2O estimate were estimated to be 59.8% in the 1950s and 37.5% in the 1990s. Seasonal N2O emissions from rice paddies in the region of middle and lower Yangtze River contributed 51% -56% to its national total. In the 1990s, N2O emissions during the rice growing season accounted for 8%-11% of the reported annual total of N2O emissions from croplands in China, suggesting that paddy rice development could have contributed to mitigating agricultural N2O emissions in the past decades. However, seasonal N2O emissions would be increased given that saving-water irrigation and nitrogen inputs are increasingly adopted in rice paddies in China.
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Agricultura/métodos , Poluentes Atmosféricos/análise , Modelos Teóricos , Óxido Nitroso/análise , Oryza/crescimento & desenvolvimento , China , Monitoramento Ambiental , Oryza/metabolismo , Estações do Ano , Solo/análiseRESUMO
In a field experiment, five fertilizer treatments including chemical fertilizer (CF), rapeseed cake + chemical fertilizer (RC + CF), wheat straw + chemical fertilizer (WS + CF), cow manure + chemical fertilizer (CM + CF), and pig manure + chemical fertilizer (PM + CF), were dedicated to examine the effect of organic materials incorporation in the rice season on N2O emissions from the following winter wheat season and to assess the climatic impacts from CH4 and N2O emissions in a rice-wheat rotation. Organic material was incorporated at the same rate (225 g x m(-2)) for organic treatments at the depth of 10 cm in the soil as the basal fertilizer just before rice transplanting. An identical synthetic nitrogen fertilizer was adopted for all treatments. Results show that the seasonal amount of N20 emissions from the following wheat season differed with organic material applied in rice season. No pronounced difference in N20 emissions was found between the CF and RC + CF treatments. In contrast with the CF treatment, however, N2O emission was decreased by 15% for the WS + CF treatment, but increased by 29% and 16% for the CM + CF and PM + CF treatments, respectively. Over the entire annual rotation cycle, N2O amount was increased by 17% for the CM + CF treatment, 7% for the PM + CF treatment, and 6% for the RC + CF treatment, but decreased by 16% for the WS + CF treatment in comparison with the CF treatment. Based on total emissions of CH4 in rice season and N2O over the entire rotation cycle, the estimation of combined Global Warming Potentials (GWPs) for CH4 and N20 shows that over a 20 years horizon or a 500 years horizon, the value of annual total GWPs was ranked in the order of RC + CF > WS + CF > CM + CF > PM + CF > CF or RC + CF > CM + CF > PM + CF > WS + CF > CF. The highest, middle and the lowest value of the GWPs per unit crop grain yield occurred for the crop residue, farmyard manure and pure synthetic fertilizer treatments, respectively. Compared to the chemical fertilizer treatment, accordingly, organic material combined with chemical fertilizer application in rice season increased climatic impacts from CH4 and N20 emissions in a rice-winter wheat rotation system.