کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
306806 513115 2006 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Differences in common bean rhizobial populations associated with soil tillage management in southern Brazil
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی انرژی های تجدید پذیر، توسعه پایدار و محیط زیست
پیش نمایش صفحه اول مقاله
Differences in common bean rhizobial populations associated with soil tillage management in southern Brazil
چکیده انگلیسی

Progressive adoption of no-tillage (NT) agriculture in the tropics is finally reversing physical, chemical, and biological erosion of soil and in Brazil, an estimated 19 Mha are now devoted to NT. Common bean (Phaseolus vulgaris L.) is a main component of Brazilian agriculture, and enhancement of yields has been achieved under NT as a result of mitigation of environmental stresses, resulting in higher N2 fixation. However, the effects of NT on rhizobial diversity are poorly understood. This study evaluated rhizobial diversity in soils planted to common bean under NT or conventional tillage (CT) systems that were compared with natural grassland used for grazing, in the State of Santa Catarina, southern Brazil. Genetic diversity was assessed by the amplification of the DNA by PCR with specific primers (BOX-PCR) and by RFLP-PCR analyses of the 16S rDNA region. A high level of diversity was observed among strains from all three systems, such that the similarity in the clustering analysis of BOX-PCR products ranged from 36% under natural grassland to only 23% for CT strains. High polymorphism was confirmed in the RFLP-PCR analysis; forty-seven different profiles were obtained, none sharing high similarity with the profiles of reference species of common bean rhizobia. These results indicate that other tropical rhizobial species remain to be described. Genetic diversity was higher among the NT than the CT rhizobial strains, especially when the RFLP-PCR profiles were considered. Genetic diversity in the natural grassland was lower than in the cropped systems, possibly due to absence of the host plant and stubble burning in winter. Average yields in the area under NT (e.g. common bean, approximately 1500 kg ha−1) have been about 30% higher than under CT, therefore high rhizobial diversity may be a parameter indicative of superior soil quality.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Soil and Tillage Research - Volume 87, Issue 2, June 2006, Pages 205–217
نویسندگان
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