Microstructure and tensile properties of TC21 titanium alloy after near-isothermal forging with different parameters plus solution treatment and aging were investigated. It is found that the residual β matrix, which ...Microstructure and tensile properties of TC21 titanium alloy after near-isothermal forging with different parameters plus solution treatment and aging were investigated. It is found that the residual β matrix, which was strengthened by fine secondary α platelets forming during aging, exists in all the samples; while primary equiaxed α phase, bent lamellar α phase and α plates are simultaneously or individually present in one sample. The strength of alloy increases proportionally with increasing the content of residual β matrix, which is the result of increasing α/β interphase boundary. The plasticity of alloy has a downward trend as the content of residual β matrix increases. This attributes to the increase of fine secondary α platelets, which are cut by dislocations during the deformation. Additionally, coarse α plates with long axis parallel to the maximum resolved shear stress(MRSS) also reduce the plasticity of TC21 alloy.展开更多
The microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment was studied by means of metallographic analysis, scanning electron microscopy (SEM), energy dispersive X-ray...The microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment was studied by means of metallographic analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and differential scanning calorimetry (DSC). The results show that serious dendritic segregation exists in studied alloy ingot. There are many eutectic phases with low melting-point at grain boundary and the distribution of main elements along interdendritic region varies periodically. Elements Zn, Mg and Cu distribute unevenly from grain boundary to the inside of alloy. With increasing the homogenization temperature or prolonging the holding time, the residual phases are dissolved into matrix α(Al) gradually during homogenization treatment, all elements become more homogenized. The overburnt temperature of studied alloy is 476.7 °C. When homogenization temperature increases to 480 °C, some spherical phases and redissolved triangular constituents at grain boundaries can be easily observed. Combined with microstructural evolution and differential scanning calorimeter, the optimum homogenization parameter is at 470 °C for 24 h.展开更多
[Objective] The aim was to explore the application of terahertz (THz) technique in pesticide recognition and residue determination. [Method] THz far-infrared spectral characteristics of 2 herbicides (butachlor and ...[Objective] The aim was to explore the application of terahertz (THz) technique in pesticide recognition and residue determination. [Method] THz far-infrared spectral characteristics of 2 herbicides (butachlor and metolachlor) were measured by THz time-domain spectroscopy (THz-TDS) under conditions of room temperature and nitrogen,meanwhile their refractive index and absorption coefficient between 0.2 and 2.2 THz were calculated by using models based on Fresenl equations. [Result] The 2 pesticides both had a series of different characteristic absorption peaks between 0.2 and 2.2 THz,respectively. Their molecular structures were similar,but there were great difference in absorption and refractive index spectrum between them. [Conclusion] THz-TDS technique is feasible to detect pesticide residues,especially there is a greater advantage in identifying the structure of similar substances.展开更多
[Objective] This study was conducted to develop a system for simultaneous determination of imidacloprid, diflubenzuron, thiabendazole and carbendazim in fruit juice by HPLC. [Method] Using acetonitrile as the extracti...[Objective] This study was conducted to develop a system for simultaneous determination of imidacloprid, diflubenzuron, thiabendazole and carbendazim in fruit juice by HPLC. [Method] Using acetonitrile as the extraction solvent, the pesticides in fruit juice were purified through a NH2 solid phase extraction (SPE) cartridge, then detected by HPLC. [Result] There was a good linear relationship between the peak area and the concentrations of imidacloprid, diflubenzuron, thiabendazole and carbendazim in a range of 0.05-5.0 μg/ml, and the linear correlation coefficient varied in a range of 0.999 0-0.999 8; the limit of detection for imidacloprid, diflubenzuron, thiabendazole and carbendazim was 0.003, 0.005, 0.003 and 0.007 mg/kg, respectively. The recovery rate of imidacloprid, diflubenzuron, thiabendazole and carbendazim standards added at three levels (0.1, 0.5 and 1.0 mg/kg) ranged from 82% to 107%, with RSD less than 4.5%. [Conclusion] The sensitivity, accuracy and precision of this method were able to meet the requirements for pesticide residue analysis.展开更多
Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on dete...Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on determination of residual protein in lincomycin hydrochloride. Methods The chromatographic conditions were SuperdexTM peptide column, 0.01 mol*L-1 phosphate buffer solution as mobile phase, and flow rate of 1 mL·min-1. Five hundred microliters of lincomycin hydrochloride solution (3 g of lincomycin hydrochloride dissolved in 10 mL of mobile phase) was injected into the chromatograph and the eluted solution was collected between 6 min and 14.5 min (protein eluted from column within this period), and the residual content of total protein in the eluted solution was assayed using Bradford assay method. Results The average recovery was more than 90% for bovine serum albumin, the calibration equation for the range of 0-12 μg·mL-1 of protein was y=-0.002 4x2+0.064 2x+0.002 9, r2=0.999 9, RSD=0.1%-0.9%, and the LOD and LOQ were 3 and 10 ng·mL-1 of protein, respectively. Conclusion The novel method for determining the residual protein in ferment antibio-tics is simple, rapid, and precise.展开更多
To investigate the residue situation of pesticides in ginseng, total 17 samples of ginseng-growing soil, ginseng roots and ginseng seeds were collected from 5 regions of Fusong County, and the contents of organochlori...To investigate the residue situation of pesticides in ginseng, total 17 samples of ginseng-growing soil, ginseng roots and ginseng seeds were collected from 5 regions of Fusong County, and the contents of organochlorine pesticide residues in the samples were detected by using ultrasonic-assisted extraction and gas chromatography with acetone-ligroin as the solvent, thereby providing suitable recommendations and scientific basis for the selection of ginseng-growing soil.展开更多
The analysis of pesticide residues in Citrus from Yichang, Danjiangkou, Zigui and Xingshan in Hubei Province was accomplished by UPLC-MS and GC-MS. The results showed that the detection rate of pesticide residues in C...The analysis of pesticide residues in Citrus from Yichang, Danjiangkou, Zigui and Xingshan in Hubei Province was accomplished by UPLC-MS and GC-MS. The results showed that the detection rate of pesticide residues in Citrus reticulate was 91.9%. The detection rate of banned pesticides was 1.6%. The detection rate of restricted pesticides was 9.5%. The detection rate of allowed pesticides was 68.3%. The detection rate of unregistered pesticides was 15.9%. The pesticide used in citrus was relatively common. Because of the banned and restricted pesticides were both in the control degree, on the whole, the quality and security of Citrus reticulata was safe.展开更多
This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem. A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl.mefenacet 4.2 ...This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem. A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl.mefenacet 4.2 g/kg granule in rice and paddy system in Hangzhou, Changsha and Nanning of China during 2010 to 2011. The results showed that the average recoveries of bensulfuron-methyl and mefenacet spiked in the paddy soil, paddy water, rice, husk and rice plant at the 3 concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 70.78% to 116.06% with the relative standard deviations of 0.91%-10.24%. The limit of detection (LOD) values of bensulfuron-methyl and mefenacet were 0.02 mg/L, and the minimum de- tection quantities were 4.0×10-9 g. The degradation dynamics test was done by spraying at a high dose (270 kg/hm2, bensulfuron-methyl active ingredient was 64.8 g/hm2, mefenacet active ingredient was 1 069.2 g/hm2) by direct spreading method 5-7 d after transplanting, and the final residual test carried out at a low dose (180 kg/hm2, bensuifuron-methyl active ingredient was 43.2 g/hm2, mefenacet active in- gredient was 712.8 g/hm2) and a high dose (270 kg/hm2). The degradation research of bensulfuron-methyl and mefenacet in paddy water, soil and rice plant suggested that the degradation curves accorded with the first-order kinetics equation, the aver- age half life of bensulfuron-methyl was 5.35, 3.05 and 3.71 d in water, soil and rice plant, respectively, and the average half life of mefenacet was 3.61, 3.29 and 3.88 d in water, soil and rice plant, respectively. The final residues of bensulfuron-methyl and mefenacet were not detected in normal harvest paddy soil, rice straw, husk and brown rice.展开更多
[Objective] A method was developed for the determination of 10 pyrethroids pesticide residues in rice by GC-MS-MS. [Method] Pyrethroids were extracted with acetonitrile, followed by a salting-out step with anhydrous m...[Objective] A method was developed for the determination of 10 pyrethroids pesticide residues in rice by GC-MS-MS. [Method] Pyrethroids were extracted with acetonitrile, followed by a salting-out step with anhydrous magnesium sulfate and sodium chloride, cleaned up by florisil solid phase extraction (SPE) cartridge, and determined by multiple reaction monitoring mode. [Result] The method showed good linearity over the range of 0.010-0.500 mg/L for 10 pyrethroid pesticide with correlation coefficients over 0.99. The detection limits were 0.005 -0.010 mg/kg. The method was validated by analyzing samples spiked with 0.05, 0.10, 0.20 mg/kg of 10 pyrethroid pesticides, respectively. The average recoveries in rice ranged from 75.0-115.5%, and the relative standard deviations (RSD) were between 3.9%-6.9%. [Conclusion] The method is easy, accurate and reliable, which can meet the requirement for the simultaneous determination and confirmation of pyrethroid pesticide residues in rice.展开更多
Quality analysis was performed to major cultivars, ‘Hongxin pomelo’ and ‘Wuzi pomelo' with uniform maturity. Total soluble solid (TSS), titratable acid, vita- min C, juice yield, edible rate, single-fruit weight...Quality analysis was performed to major cultivars, ‘Hongxin pomelo’ and ‘Wuzi pomelo' with uniform maturity. Total soluble solid (TSS), titratable acid, vita- min C, juice yield, edible rate, single-fruit weight and pesticide residues of the 2 cultivars were detected. The results showed that: the TSS contents of ‘Hongxin pomelo' and ‘Wuzi pomelo' were in the range of 8%-12%, the vitamin C contents were in the range of 0.3-0.6 g/L, the juice yields were in the range of 56%-68%, the edible rates were in the range of 52%-68%, and the single-fruit weights were in the range of 1-2.5 kg. The titratable acid content was higher in ‘Hongxin pomelo' than in ‘Wuzi pomelo'. Only Dursban and imidacloprid were detected at low con- centrations in pericarp, and the residues of the 3 pesticides were all lower than their detection limits. Therefore, honey pomelo produced in Hainan all could be ate safely.展开更多
[Objective] This study was conducted to investigate the fresh eating-quality of Hainan Iongan. [Methed] The quality analysis was conducted on on-season and off-season Iongan, which are main cultivars in Hainan consist...[Objective] This study was conducted to investigate the fresh eating-quality of Hainan Iongan. [Methed] The quality analysis was conducted on on-season and off-season Iongan, which are main cultivars in Hainan consistent in maturity. In order to understand the quality characteristics of Hainan fresh Iongan, saccharide contents, vitamin C content, edible rate, TSS, weight of single fruit, weight per fruit cluster and pesticide residues were detected in this study. [Result] There were no significant differences in quality between on-season and off-season Iongan, and the content of TSS in off-season fruit was slightly higher than that in on-season Iongan. The two main cultivars ‘Shixia' and 'Chuliang' in Hainan differed significantly in edible quality. The weight of single fruit and edible rate of ‘Chuliang' were slightly higher than those of ‘Shixia' Iongan, and their sucrose contents were nearly equivalent. Vitamin C and TSS contents in ‘Shixia' Ionganwere higher than those in ‘Chuliang'.‘Shixia' had a monosaccharide content significantly higher than ‘Chuliang', while its sucrose content was lower than ‘Chuliang'. Only low contents of residual cypermethrin and diflubenzuron were detected in pericarp, and the contents of the 9 pesticides in fruit flesh were all lower than their detection limits. [Conclusion] Longan fruit produced in Hainan could all be eaten safely.展开更多
[Objective] The paper was to detect the residue of buprofezin in citrus and soil.[Method] Gas chromatography(GC)method was used to measure the residue of buprofezin in citrus and soil.[Result] The average recovery r...[Objective] The paper was to detect the residue of buprofezin in citrus and soil.[Method] Gas chromatography(GC)method was used to measure the residue of buprofezin in citrus and soil.[Result] The average recovery rate of buprofezin in entire citrus fruit was 96.17%-97.38%,and the variation coefficient was 6.10%-9.07%;the average recovery rate in pulp was 95.24%-105.46%,and the variation coefficient was 3.30%-6.01%;the average recovery rate in peel was 88.76%-93.64%,and the variation coefficient was 5.12%-6.27%;the average recovery rate in soil was 97.79%-104.3%,and the variation coefficient was 2.45%-9.21%.The degradation dynamics and the final residue results of buprofezin in citrus and soil showed that the degradation half-lives in citrus in Changsha(Hunan),Hangzhou(Zhejiang)and Guiyang(Guizhou)were 7.65,7.64 and 8.40 d,and the degradation half-lives in soil in three places were 13.75,9.97 and 10.18 d,respectively.[Conclusion] When 25% buprofezin SC watered agent were sprayed in citrus fruits for 2-3 times according to the recommended dose of 166.7-250.0 mg/L,the safe period of buprofezin in citrus could be set as 14 d.展开更多
ObjectiveThe aim was to explore the movement of nitrate nitrogen in tall-fescue soils by different kinds of slow release nitrogen fertilizers. MethodBased on infiltration-tanks and test plots, a new and environment fr...ObjectiveThe aim was to explore the movement of nitrate nitrogen in tall-fescue soils by different kinds of slow release nitrogen fertilizers. MethodBased on infiltration-tanks and test plots, a new and environment friendly fertilizer was explored. ResultThe results show that compared with urea treatment, slow-release nitrogen fertilizer treatments could reduce nitrate nitrogen content and leaching amount in soils. Compared with PCU30 and IU treatments, the PCU60 treatment became more efficient in reducing nitrate content and leaching amount in 0-90 cm soil layer. ConclusionIn summary, slow-release nitrogen fertilizer, which can reduce soil nitrate content and leaching losses, is a kind of novel fertilizer with high environmental benefit and promising application.展开更多
[Objective] The aim was to investigate pesticide use in Qujing city and explore the control measures.[Method] Surveys were made on pesticide use by farmers in five vegetable bases in Qujing city by questionnaires to s...[Objective] The aim was to investigate pesticide use in Qujing city and explore the control measures.[Method] Surveys were made on pesticide use by farmers in five vegetable bases in Qujing city by questionnaires to study pesticide use and existing problems by farmers.[Result] Some problems existed in pesticide use in Qujing,such as non-standard pesticide source,lower-recognition of pesticide and impacts of pesticide residues on environment,and without professional guidance.[Conclusion] The existing problems can be resolved by enhancing technical trainings of technicians or pesticide managers,strengthening pesticide promotion,and reinforcing examination of pesticide residues.展开更多
In order to study the difference between cauliflower varieties with ball well protected and unprotected in terms of pesticide residue and its causes, Jinpin 70, a new male sterile cauliflower variety with ball well pr...In order to study the difference between cauliflower varieties with ball well protected and unprotected in terms of pesticide residue and its causes, Jinpin 70, a new male sterile cauliflower variety with ball well protected, and Xuebao with ball unprotected were sprayed with high-toxic pesticide phorate and efficient bio-pesticide emamectin benzoate at a regular dose to investigate the impact of different cauliflower varieties on the pesticide residue. The results showed that from the 3rd to the 5th day after spraying, phorate and emamectin benzoate residues in Jinpin 70 with ball well protected reduced by 76.47%-87.65% and 67.86%-80.82% re- spectively compared with Xubao, and decreased by 9.23%-81.82% and 57.14%- 79.84% respectively compared with Jinpin 70 with ball unprotected. The results above demonstrates that inner leaves of cauliflower with ball well protected can prevent the ball from being polluted by phorate and emamectin benzoate, thereby improving its edible safety.展开更多
ObjectiveThe aim was to increase farmers’ income and reduce the waste of fertilizer by exploring effects of N, P and K fertilizations on vegetable yields and the accumulation of N, P and K in vegetable and soils. Met...ObjectiveThe aim was to increase farmers’ income and reduce the waste of fertilizer by exploring effects of N, P and K fertilizations on vegetable yields and the accumulation of N, P and K in vegetable and soils. MethodThe fertilization tests were conducted on tomato, cauliflower and celery in greenhouses. ResultWhen N, P and K were not applied in tomato, cauliflower or celery, the yields reduced in 6.0%-13.8% and total annual income reduced by 39 220, 36 902 and 22 023 yuan/hm 2 respectively, suggesting that N, P and K are limiting factors of yield. The absorbed N amounts of tomato and cauliflower were higher compared with celery; the absorbed P amount of cauliflower was higher compared with tomato and celery; the absorbed K amount of tomato was the highest, followed by celery and cauliflower. The absorbed N in tomato fruit was lower than that of cauliflower and the absorbed N amount of other parts of tomato was also lower. Furthermore, the absorbed amounts of P and K by tomato and cauliflower fruits were higher than it absorbed by the other parts, especially the absorbed of K was significantly high. Total absorbed amounts of N, P and K from high to low were cauliflower, tomato and celery. After harvesting of tomato, cauliflower and celery, N, P and K in soils were all higher compared with soils before planting. Influenced by fertilizers, residual N content in soils grown with tomato and residual P content in soils grown with celery both doubled compared with base soils. Cauliflower plants were not applied with organic fertilizer, and residual N and K contents in soils were lower compared with tomato and celery. ConclusionResidual P content in soils is higher, which is a kind of waste and would cause pollution on soils. It is necessary to improve the proportion of organic and inorganic fertilizers in fertilization.展开更多
This study was conducted to establish an analytical method for endosulfan residue in apple. Samples were extracted with 30 ml of acetone : ethyl acetate (9:1), purified with FlorisiL (containing activated carbon...This study was conducted to establish an analytical method for endosulfan residue in apple. Samples were extracted with 30 ml of acetone : ethyl acetate (9:1), purified with FlorisiL (containing activated carbon), and detected by GC. Under those detection conditions, the detection limits of α-endosulfan, 15-endosulfan and endosulfate were 10^-11, 10^-11, and 2.5×10^-11 g, respectively. The recoveries of α-en- dosulfan were in the range of 89.49%-95.34%, with CVs in the range of 1.45%- 2.69%; the recoveries of β-endosulfan were in the range of 99.35%-100.63%, with CVs in the range of 1.39%-4.72%; and the recoveries of endosulfan suffate were in the range of 95.32%-101.15%, with CVs in the range of 1.19%-3.21%. The accu- racy, precision and sensitivity of the method all satisfy the requirements of pesticide residue analysis.展开更多
基金Projects(51205319,51101119)supported by the National Natural Science Foundation of China
文摘Microstructure and tensile properties of TC21 titanium alloy after near-isothermal forging with different parameters plus solution treatment and aging were investigated. It is found that the residual β matrix, which was strengthened by fine secondary α platelets forming during aging, exists in all the samples; while primary equiaxed α phase, bent lamellar α phase and α plates are simultaneously or individually present in one sample. The strength of alloy increases proportionally with increasing the content of residual β matrix, which is the result of increasing α/β interphase boundary. The plasticity of alloy has a downward trend as the content of residual β matrix increases. This attributes to the increase of fine secondary α platelets, which are cut by dislocations during the deformation. Additionally, coarse α plates with long axis parallel to the maximum resolved shear stress(MRSS) also reduce the plasticity of TC21 alloy.
基金Project (2012CB619503) supported by the National Basic Research Program of China
文摘The microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment was studied by means of metallographic analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and differential scanning calorimetry (DSC). The results show that serious dendritic segregation exists in studied alloy ingot. There are many eutectic phases with low melting-point at grain boundary and the distribution of main elements along interdendritic region varies periodically. Elements Zn, Mg and Cu distribute unevenly from grain boundary to the inside of alloy. With increasing the homogenization temperature or prolonging the holding time, the residual phases are dissolved into matrix α(Al) gradually during homogenization treatment, all elements become more homogenized. The overburnt temperature of studied alloy is 476.7 °C. When homogenization temperature increases to 480 °C, some spherical phases and redissolved triangular constituents at grain boundaries can be easily observed. Combined with microstructural evolution and differential scanning calorimeter, the optimum homogenization parameter is at 470 °C for 24 h.
基金Supported by Special Fund for Scientific Research on Public Welfare by China Quality Monitoring Bureau (200910181)National Natural Science Foundation of China (60902095)~~
文摘[Objective] The aim was to explore the application of terahertz (THz) technique in pesticide recognition and residue determination. [Method] THz far-infrared spectral characteristics of 2 herbicides (butachlor and metolachlor) were measured by THz time-domain spectroscopy (THz-TDS) under conditions of room temperature and nitrogen,meanwhile their refractive index and absorption coefficient between 0.2 and 2.2 THz were calculated by using models based on Fresenl equations. [Result] The 2 pesticides both had a series of different characteristic absorption peaks between 0.2 and 2.2 THz,respectively. Their molecular structures were similar,but there were great difference in absorption and refractive index spectrum between them. [Conclusion] THz-TDS technique is feasible to detect pesticide residues,especially there is a greater advantage in identifying the structure of similar substances.
基金Supported by the Special Funds for Supervision on the Quality and Safety of Agricultural Products(GJFP201601503)~~
文摘[Objective] This study was conducted to develop a system for simultaneous determination of imidacloprid, diflubenzuron, thiabendazole and carbendazim in fruit juice by HPLC. [Method] Using acetonitrile as the extraction solvent, the pesticides in fruit juice were purified through a NH2 solid phase extraction (SPE) cartridge, then detected by HPLC. [Result] There was a good linear relationship between the peak area and the concentrations of imidacloprid, diflubenzuron, thiabendazole and carbendazim in a range of 0.05-5.0 μg/ml, and the linear correlation coefficient varied in a range of 0.999 0-0.999 8; the limit of detection for imidacloprid, diflubenzuron, thiabendazole and carbendazim was 0.003, 0.005, 0.003 and 0.007 mg/kg, respectively. The recovery rate of imidacloprid, diflubenzuron, thiabendazole and carbendazim standards added at three levels (0.1, 0.5 and 1.0 mg/kg) ranged from 82% to 107%, with RSD less than 4.5%. [Conclusion] The sensitivity, accuracy and precision of this method were able to meet the requirements for pesticide residue analysis.
文摘Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on determination of residual protein in lincomycin hydrochloride. Methods The chromatographic conditions were SuperdexTM peptide column, 0.01 mol*L-1 phosphate buffer solution as mobile phase, and flow rate of 1 mL·min-1. Five hundred microliters of lincomycin hydrochloride solution (3 g of lincomycin hydrochloride dissolved in 10 mL of mobile phase) was injected into the chromatograph and the eluted solution was collected between 6 min and 14.5 min (protein eluted from column within this period), and the residual content of total protein in the eluted solution was assayed using Bradford assay method. Results The average recovery was more than 90% for bovine serum albumin, the calibration equation for the range of 0-12 μg·mL-1 of protein was y=-0.002 4x2+0.064 2x+0.002 9, r2=0.999 9, RSD=0.1%-0.9%, and the LOD and LOQ were 3 and 10 ng·mL-1 of protein, respectively. Conclusion The novel method for determining the residual protein in ferment antibio-tics is simple, rapid, and precise.
基金Supported by Scientific and Technological Research Project of Education Department of Jilin Province during the 12th Five-Year Plan(111022013033)Seed Fund of Jilin Academy of Agricultural Sciences(119032014004)Project of Science and Technology Department of Jilin Province(111042014010)~~
文摘To investigate the residue situation of pesticides in ginseng, total 17 samples of ginseng-growing soil, ginseng roots and ginseng seeds were collected from 5 regions of Fusong County, and the contents of organochlorine pesticide residues in the samples were detected by using ultrasonic-assisted extraction and gas chromatography with acetone-ligroin as the solvent, thereby providing suitable recommendations and scientific basis for the selection of ginseng-growing soil.
基金Supported by Special Funds of National Agricultural product Quality and Safety Risk Assessment(GJFP201600402)Youth Foundation of Hubei Academy of Agricultural Sciences(2015NKYJJ36)~~
文摘The analysis of pesticide residues in Citrus from Yichang, Danjiangkou, Zigui and Xingshan in Hubei Province was accomplished by UPLC-MS and GC-MS. The results showed that the detection rate of pesticide residues in Citrus reticulate was 91.9%. The detection rate of banned pesticides was 1.6%. The detection rate of restricted pesticides was 9.5%. The detection rate of allowed pesticides was 68.3%. The detection rate of unregistered pesticides was 15.9%. The pesticide used in citrus was relatively common. Because of the banned and restricted pesticides were both in the control degree, on the whole, the quality and security of Citrus reticulata was safe.
基金Supported Nanning Major Scientific and Technological Project of New Patented Product Industrialization(201106055D)Agrochemical Residual Test Project of Ministry of China(2010H216)Youth Science Foundation of Hunan Agricultural University(15QN30)~~
文摘This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem. A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl.mefenacet 4.2 g/kg granule in rice and paddy system in Hangzhou, Changsha and Nanning of China during 2010 to 2011. The results showed that the average recoveries of bensulfuron-methyl and mefenacet spiked in the paddy soil, paddy water, rice, husk and rice plant at the 3 concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 70.78% to 116.06% with the relative standard deviations of 0.91%-10.24%. The limit of detection (LOD) values of bensulfuron-methyl and mefenacet were 0.02 mg/L, and the minimum de- tection quantities were 4.0×10-9 g. The degradation dynamics test was done by spraying at a high dose (270 kg/hm2, bensulfuron-methyl active ingredient was 64.8 g/hm2, mefenacet active ingredient was 1 069.2 g/hm2) by direct spreading method 5-7 d after transplanting, and the final residual test carried out at a low dose (180 kg/hm2, bensuifuron-methyl active ingredient was 43.2 g/hm2, mefenacet active in- gredient was 712.8 g/hm2) and a high dose (270 kg/hm2). The degradation research of bensulfuron-methyl and mefenacet in paddy water, soil and rice plant suggested that the degradation curves accorded with the first-order kinetics equation, the aver- age half life of bensulfuron-methyl was 5.35, 3.05 and 3.71 d in water, soil and rice plant, respectively, and the average half life of mefenacet was 3.61, 3.29 and 3.88 d in water, soil and rice plant, respectively. The final residues of bensulfuron-methyl and mefenacet were not detected in normal harvest paddy soil, rice straw, husk and brown rice.
文摘[Objective] A method was developed for the determination of 10 pyrethroids pesticide residues in rice by GC-MS-MS. [Method] Pyrethroids were extracted with acetonitrile, followed by a salting-out step with anhydrous magnesium sulfate and sodium chloride, cleaned up by florisil solid phase extraction (SPE) cartridge, and determined by multiple reaction monitoring mode. [Result] The method showed good linearity over the range of 0.010-0.500 mg/L for 10 pyrethroid pesticide with correlation coefficients over 0.99. The detection limits were 0.005 -0.010 mg/kg. The method was validated by analyzing samples spiked with 0.05, 0.10, 0.20 mg/kg of 10 pyrethroid pesticides, respectively. The average recoveries in rice ranged from 75.0-115.5%, and the relative standard deviations (RSD) were between 3.9%-6.9%. [Conclusion] The method is easy, accurate and reliable, which can meet the requirement for the simultaneous determination and confirmation of pyrethroid pesticide residues in rice.
基金Supported by "948" Project of Ministry of Agriculture of China:Study on the Introduction of Agricultural Biological Resources,the Demand of Agricultural Technology and Collection of Policy Information of Africa,Oceania and Other Island Countries(2016-X17)~~
文摘Quality analysis was performed to major cultivars, ‘Hongxin pomelo’ and ‘Wuzi pomelo' with uniform maturity. Total soluble solid (TSS), titratable acid, vita- min C, juice yield, edible rate, single-fruit weight and pesticide residues of the 2 cultivars were detected. The results showed that: the TSS contents of ‘Hongxin pomelo' and ‘Wuzi pomelo' were in the range of 8%-12%, the vitamin C contents were in the range of 0.3-0.6 g/L, the juice yields were in the range of 56%-68%, the edible rates were in the range of 52%-68%, and the single-fruit weights were in the range of 1-2.5 kg. The titratable acid content was higher in ‘Hongxin pomelo' than in ‘Wuzi pomelo'. Only Dursban and imidacloprid were detected at low con- centrations in pericarp, and the residues of the 3 pesticides were all lower than their detection limits. Therefore, honey pomelo produced in Hainan all could be ate safely.
基金Supported by National Science&Technology Infrastructure-National Infrastructure of Agriculture Germplasm Resources"National infrastructure of tropical crops germplasm resources/NICGR2016-067"China Agriculture Research System(CARS-33-25)~~
文摘[Objective] This study was conducted to investigate the fresh eating-quality of Hainan Iongan. [Methed] The quality analysis was conducted on on-season and off-season Iongan, which are main cultivars in Hainan consistent in maturity. In order to understand the quality characteristics of Hainan fresh Iongan, saccharide contents, vitamin C content, edible rate, TSS, weight of single fruit, weight per fruit cluster and pesticide residues were detected in this study. [Result] There were no significant differences in quality between on-season and off-season Iongan, and the content of TSS in off-season fruit was slightly higher than that in on-season Iongan. The two main cultivars ‘Shixia' and 'Chuliang' in Hainan differed significantly in edible quality. The weight of single fruit and edible rate of ‘Chuliang' were slightly higher than those of ‘Shixia' Iongan, and their sucrose contents were nearly equivalent. Vitamin C and TSS contents in ‘Shixia' Ionganwere higher than those in ‘Chuliang'.‘Shixia' had a monosaccharide content significantly higher than ‘Chuliang', while its sucrose content was lower than ‘Chuliang'. Only low contents of residual cypermethrin and diflubenzuron were detected in pericarp, and the contents of the 9 pesticides in fruit flesh were all lower than their detection limits. [Conclusion] Longan fruit produced in Hainan could all be eaten safely.
基金Supported by Pesticide Testing Project of Ministry of Agriculture(NYCL20080368)~~
文摘[Objective] The paper was to detect the residue of buprofezin in citrus and soil.[Method] Gas chromatography(GC)method was used to measure the residue of buprofezin in citrus and soil.[Result] The average recovery rate of buprofezin in entire citrus fruit was 96.17%-97.38%,and the variation coefficient was 6.10%-9.07%;the average recovery rate in pulp was 95.24%-105.46%,and the variation coefficient was 3.30%-6.01%;the average recovery rate in peel was 88.76%-93.64%,and the variation coefficient was 5.12%-6.27%;the average recovery rate in soil was 97.79%-104.3%,and the variation coefficient was 2.45%-9.21%.The degradation dynamics and the final residue results of buprofezin in citrus and soil showed that the degradation half-lives in citrus in Changsha(Hunan),Hangzhou(Zhejiang)and Guiyang(Guizhou)were 7.65,7.64 and 8.40 d,and the degradation half-lives in soil in three places were 13.75,9.97 and 10.18 d,respectively.[Conclusion] When 25% buprofezin SC watered agent were sprayed in citrus fruits for 2-3 times according to the recommended dose of 166.7-250.0 mg/L,the safe period of buprofezin in citrus could be set as 14 d.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201003014)Youth Foundation of Beijing Academy of Agricultural and Forestry Sciences(QNJJ201311)~~
文摘ObjectiveThe aim was to explore the movement of nitrate nitrogen in tall-fescue soils by different kinds of slow release nitrogen fertilizers. MethodBased on infiltration-tanks and test plots, a new and environment friendly fertilizer was explored. ResultThe results show that compared with urea treatment, slow-release nitrogen fertilizer treatments could reduce nitrate nitrogen content and leaching amount in soils. Compared with PCU30 and IU treatments, the PCU60 treatment became more efficient in reducing nitrate content and leaching amount in 0-90 cm soil layer. ConclusionIn summary, slow-release nitrogen fertilizer, which can reduce soil nitrate content and leaching losses, is a kind of novel fertilizer with high environmental benefit and promising application.
文摘[Objective] The aim was to investigate pesticide use in Qujing city and explore the control measures.[Method] Surveys were made on pesticide use by farmers in five vegetable bases in Qujing city by questionnaires to study pesticide use and existing problems by farmers.[Result] Some problems existed in pesticide use in Qujing,such as non-standard pesticide source,lower-recognition of pesticide and impacts of pesticide residues on environment,and without professional guidance.[Conclusion] The existing problems can be resolved by enhancing technical trainings of technicians or pesticide managers,strengthening pesticide promotion,and reinforcing examination of pesticide residues.
基金Supported by the Technology System Project of National Vegetable Industry(CARS-25-A-13)Science and Technology Planning Project of Tianjin City(12ZCDZNC03600)Major Science and Technology Engineering Project of Tianjin City(12ZCDZNC03500)~~
文摘In order to study the difference between cauliflower varieties with ball well protected and unprotected in terms of pesticide residue and its causes, Jinpin 70, a new male sterile cauliflower variety with ball well protected, and Xuebao with ball unprotected were sprayed with high-toxic pesticide phorate and efficient bio-pesticide emamectin benzoate at a regular dose to investigate the impact of different cauliflower varieties on the pesticide residue. The results showed that from the 3rd to the 5th day after spraying, phorate and emamectin benzoate residues in Jinpin 70 with ball well protected reduced by 76.47%-87.65% and 67.86%-80.82% re- spectively compared with Xubao, and decreased by 9.23%-81.82% and 57.14%- 79.84% respectively compared with Jinpin 70 with ball unprotected. The results above demonstrates that inner leaves of cauliflower with ball well protected can prevent the ball from being polluted by phorate and emamectin benzoate, thereby improving its edible safety.
基金Supported by Tianjin Municipal Science and Technology Commission Program(07ZCGYNC00800)International Plant Nutrition Institute Program(Tianjin-2008,Tianjin-2009)Agricultural Eco-protection Program of Ministry of Agriculture(2110402-201258)~~
文摘ObjectiveThe aim was to increase farmers’ income and reduce the waste of fertilizer by exploring effects of N, P and K fertilizations on vegetable yields and the accumulation of N, P and K in vegetable and soils. MethodThe fertilization tests were conducted on tomato, cauliflower and celery in greenhouses. ResultWhen N, P and K were not applied in tomato, cauliflower or celery, the yields reduced in 6.0%-13.8% and total annual income reduced by 39 220, 36 902 and 22 023 yuan/hm 2 respectively, suggesting that N, P and K are limiting factors of yield. The absorbed N amounts of tomato and cauliflower were higher compared with celery; the absorbed P amount of cauliflower was higher compared with tomato and celery; the absorbed K amount of tomato was the highest, followed by celery and cauliflower. The absorbed N in tomato fruit was lower than that of cauliflower and the absorbed N amount of other parts of tomato was also lower. Furthermore, the absorbed amounts of P and K by tomato and cauliflower fruits were higher than it absorbed by the other parts, especially the absorbed of K was significantly high. Total absorbed amounts of N, P and K from high to low were cauliflower, tomato and celery. After harvesting of tomato, cauliflower and celery, N, P and K in soils were all higher compared with soils before planting. Influenced by fertilizers, residual N content in soils grown with tomato and residual P content in soils grown with celery both doubled compared with base soils. Cauliflower plants were not applied with organic fertilizer, and residual N and K contents in soils were lower compared with tomato and celery. ConclusionResidual P content in soils is higher, which is a kind of waste and would cause pollution on soils. It is necessary to improve the proportion of organic and inorganic fertilizers in fertilization.
基金Supported by National Key Research and Development Program of China(2016YFD0200205-2)~~
文摘This study was conducted to establish an analytical method for endosulfan residue in apple. Samples were extracted with 30 ml of acetone : ethyl acetate (9:1), purified with FlorisiL (containing activated carbon), and detected by GC. Under those detection conditions, the detection limits of α-endosulfan, 15-endosulfan and endosulfate were 10^-11, 10^-11, and 2.5×10^-11 g, respectively. The recoveries of α-en- dosulfan were in the range of 89.49%-95.34%, with CVs in the range of 1.45%- 2.69%; the recoveries of β-endosulfan were in the range of 99.35%-100.63%, with CVs in the range of 1.39%-4.72%; and the recoveries of endosulfan suffate were in the range of 95.32%-101.15%, with CVs in the range of 1.19%-3.21%. The accu- racy, precision and sensitivity of the method all satisfy the requirements of pesticide residue analysis.