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251.
Tillage and crop residue effects on soil carbon and carbon dioxide emission in corn-soybean rotations 总被引:11,自引:0,他引:11
Soil C change and CO2 emission due to different tillage systems need to be evaluated to encourage the adoption of conservation practices to sustain soil productivity and protect the environment. We hypothesize that soil C storage and CO2 emission respond to conservation tillage differently from conventional tillage because of their differential effects on soil properties. This study was conducted from 1998 through 2001 to evaluate tillage effects on soil C storage and CO2 emission in Clarion-Nicollet-Webster soil association in a corn [Zea mays L.]-soybean [Glycine max (L.) Merr.] rotation in Iowa. Treatments included no-tillage with and without residue, strip-tillage, deep rip, chisel plow, and moldboard plow. No-tillage with residue and strip-tillage significantly increased total soil organic C (TC) and mineral fraction C (MFC) at the 0- to 5- and 5- to 10-cm soil depths compared with chisel plow after 3 yr of tillage practices. Soil CO2 emission was lower for less intensive tillage treatments compared with moldboard plow, with the greatest differences occurring immediately after tillage operations. Cumulative soil CO2 emission was 19 to 41% lower for less intensive tillage treatments than moldboard plow, and it was 24% less for no-tillage with residue than without residue during the 480-h measurement period. Estimated soil mineralizable C pool was reduced by 22 to 66% with less intensive tillage treatments compared with moldboard plow. Adopting less intensive tillage systems such as no-tillage, strip-tillage, deep rip, and chisel plow and better crop residue cover are effective in reducing CO2 emission and thus improving soil C sequestration in a corn-soybean rotation. 相似文献
252.
Kaotar Nayme Abouddihaj Barguigua Brahim Bouchrif Bouchra Karraouan Fatima El Otmani Naima Elmdaghri 《Journal of environmental science and health. Part. B》2017,52(2):107-114
This study was conducted to assess the retail food as a possible vehicle for antimicrobial resistant, particularly quinolones resistant and pathogenic Escherichia coli. We determined the prevalence and characteristics of nalidixic acid (Nal) resistant E. coli isolates from diverse retail food samples. In all, 70 (28%) of 250 E. coli isolates studied were Nal-resistant E. coli and 91% of these were multi-drug resistant. Plasmid mediated quinolone resistance genes were identified in 32 isolates, including aac(6′)-Ib-cr (n = 16), qnrS1 (n = 11) and qnrB19 (n = 7). Mutations in gyr A and par C genes were detected among 80% of the isolates, and the isolates showed substitution Ser83-Leu and Asp87-Asn in gyrA and Ser80-Ile in parC. In addition, three different gene cassettes were identified (aadA1, aadA7, aac(3)-Id) in 18%. Virulence-associated genes stx1, eae, sfa, hlyA and stx2 were found in six (8%), three (4%), two (3%), three (4%) and three (4%) isolates, respectively. E. coli isolates of phylogenetic group A were dominant (64%, 45/70). Pulsed field gel electrophoresis revealed none epidemiological relationship between these isolates. The results of this work report the higher frequency of Nal-resistant E. coli isolates from Moroccan retail food samples including MDR and pathogenic isolates. 相似文献
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Neda Saraygord-Afshari Fereshteh Abbasisiar Parviz Abdolmaleki Mahdi Ghiassi-Nejad Ali Attarilar 《The Environmentalist》2011,31(3):308-314
Thirty-eight different milk and milk powder samples from Tehran-Iran were collected and analyzed for 90Sr activity using a method in which the daughter product of 90Sr decay (90Y) was extracted by tributyl phosphate from ashed milk. 90Y was then back extracted with water, and oxalate was precipitated . Following the sample analyzing, beta counting was performed
with an ultralow-level liquid scintillation spectrometer. The quality control and assurance of the method were obtained by
standard samples prepared with an IAEA-certified reference material. The mean determined 90Sr activity concentration in the analyzed milk and milk powder (0.225 ± 0.042 and 0.216 ± 0.024 Bq kg−1, respectively) showed that the radioactivity concentration in our samples was too low to induce biological hazards. These
data can provide useful information of the background level of contamination, which in turn can be used in the following environmental
monitoring programs. 相似文献
258.
Salhi Anas Esserrar Sana Nechchadi Bouchra El Amine Ghanjaoui Mohammed Aguedache Abdelkahhar El Krati Mohammed Tahiri Soufiane 《Environmental science and pollution research international》2022,29(31):46778-46787
Environmental Science and Pollution Research - The aim of this work is the study of the photocatalytic degradation of Acid Black 24 dye (AB24), in a continuous flow cascade reactor, using titanium... 相似文献
259.
Mohammadi Keyhan Sani Mahmood Alizadeh Safaei Payam Rahmani Jamal Molaee-Aghaee Ebrahim Jafari Seid Mahdi 《Environmental science and pollution research international》2022,29(41):62030-62041
Environmental Science and Pollution Research - Worldwide use of glyphosate is constantly increasing and its residues are detected in drinking water, agriculture, and food products. There are... 相似文献
260.
Sedeño-Díaz Jacinto Elías López-López Eugenia Rodríguez-Romero A. Joseph Leos Karla Fierro Martínez Melissa Tiburcio Sánchez Oscar Emiliano Escobar 《Environmental science and pollution research international》2022,29(41):61630-61642
Environmental Science and Pollution Research - Qanats in the aquifer of the Tehuacán Valley (Mexico) represent an ancient way of using groundwater that is still practiced today. They are used... 相似文献