Diversity and activity of free-living nitrogen-fixing bacteria and total bacteria in organic and conventionally managed soils.
نویسندگان
چکیده
Agricultural soils are heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, the molecular ecology of the total bacterial and free-living nitrogen-fixing communities in soils from the Nafferton Factorial Systems Comparison (NFSC) study in northeast England were examined. The field experiment was factorial in design, with organic versus conventional crop rotation, crop protection, and fertility management factors. Soils were sampled on three dates (March, June, and September) in 2007. Total RNA was extracted from all soil samples and reverse transcribed. Denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) were used to analyze nifH and 16S rRNA genes in order to study free-living diazotrophs and the total bacterial community, respectively. Crop rotation was shown to have a significant effect on total bacterial diversity (and that of free-living N fixers) (P ≤ 0.001). On all three dates, nifH activity was higher in the conventional crop rotation. In contrast, qPCR analysis of free-living N fixers indicated significantly higher levels of activity in conventionally fertilized plots in June (P = 0.0324) and in plots with organic crop protection in September (P = 0.0143). To our knowledge, the effects of organic and conventional farming systems on free-living diazotrophs have never been studied. An increased understanding of the impacts of management practices on free-living N fixers could allow modifications in soil management practices to optimize the activity of these organisms.
منابع مشابه
Impacts of Organic and Conventional Crop Management on Diversity and Activity of Free-Living Nitrogen Fixing Bacteria and Total Bacteria Are Subsidiary to Temporal Effects
A three year field study (2007-2009) of the diversity and numbers of the total and metabolically active free-living diazotophic bacteria and total bacterial communities in organic and conventionally managed agricultural soil was conducted using the Nafferton Factorial Systems Comparison (NFSC) study, in northeast England. Fertility management appeared to have little impact on both diazotrophic ...
متن کاملEffect of Abandonment on Diversity and Abundance of Free-Living Nitrogen-Fixing Bacteria and Total Bacteria in the Cropland Soils of Hulun Buir, Inner Mongolia
In Inner Mongolia, steppe grasslands face desertification or degradation because of human over activity. One of the reasons for this condition is that croplands have been abandoned after inappropriate agricultural management. The soils in these croplands present heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this st...
متن کاملEffect of Different Fertilization Systems on Yield and Seed Mineral Elements of Pumpkin
ABSTRACT- To investigate the effects of bio-chemical and organic fertilizers on yield and seeds NPK contents of pumpkin (Cucurbita pepo var. styriaca), an experiment was conducted at the Research Farm of Kurdistan University in 2009 growing season. Treatments were included 1) control, 2) seeds inoculated with free-living N fixing bacteria (NFB), 3) seeds inoculated with phosphate-solubilizing b...
متن کاملNitrogen Fixation Associated with Sugarcane
Nitrogen fixation associated with sugarcane was monitored ushg acetylene reducti,on tests and bacteriological techniques. Soil cores and trash from cane fields showed acetylene reducing activity. This activity was usually low in association with sandy soils. Where high activity was detected in soil cores it correlat~d with the wet weight of roots in each core. Nitrogen-fixing bacteria resemblin...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Applied and environmental microbiology
دوره 77 3 شماره
صفحات -
تاریخ انتشار 2011