Biological nitrogen fixation by soybean and fate of applied 15N-fertilizer in succeeding wheat under conventional tillage and conservation agriculture practices

2017 ◽  
Vol 107 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Milkha S. Aulakh ◽  
Ashok K. Garg ◽  
Joginder S. Manchanda ◽  
Gerd Dercon ◽  
Minh-Long Nguyen
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Conservation Agriculture ◽  
Conventional Tillage ◽  
15N Fertilizer ◽  
Biological Nitrogen

scholarly journals Conservation Agriculture in Zambia: Effects on Selected Soil Properties and Biological Nitrogen Fixation in Soya Beans (Glycine max (L.) Merr)

2014 ◽  
Vol 3 (3) ◽  
pp. 28 ◽  
Author(s):  
Jane Muchabi ◽  
Obed I. Lungu ◽  
Alice M. Mweetwa
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Soil Respiration ◽  
Soil Properties ◽  
Biological Nitrogen Fixation ◽  
Management Practices ◽  
Conservation Agriculture ◽  
Crop Productivity ◽  
Conventional Tillage ◽  
Biological Nitrogen

<p>Conservation agriculture has been promoted in Zambia as a strategy to mitigate some of the negative effects arising from conventional tillage practices. Conservation agriculture offers several potential benefits on soil properties. However, these benefits and impacts vary across agro ecological regions and management practices. This study investigated changes, over time, associated with the practice of conservation agriculture in selected soil chemical, physical and biological properties, including an assessment of the effects on soil respiration, nodulation and biological nitrogen fixation in soya beans (<em>Glycine max </em>(L.) Merr). Six paired soil samples were collected from conservation agriculture and conventional tillage fields. Fields under conservation agriculture were 4, 7 and 16 years old while those under conventional tillage had been cultivated for over 18 years. Changes in soil properties due to conservation agriculture practice were determined using published laboratory procedures and compared using the paired t-test at 95% confidence level. The results indicated significantly higher soil pH, soil organic carbon, nodulation and biological nitrogen fixation under conservation agriculture than conventional tillage after seven years of practice. The study also showed significantly higher total porosity, soil microbial biomass, soil respiration and lower soil bulk density after sixteen years of practice. Based on these results, the practice of conservation agriculture has potential to improve crop productivity by improving the different aspects of soil fertility, the length of time before this is realized notwithstanding. Further studies that compare several conservation agriculture systems are recommended in other agro-ecological zones of the country to validate these findings.</p>

scholarly journals Potential Impacts of Changing Precipitation Patterns on Biological Nitrogen Fixation in Soybean (Glycine Max L.) as Mediated by Landscape Position and Tillage

2021 ◽  
Author(s):  
Kathryn Glanville ◽  
G. Philip Robertson
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Conventional Tillage ◽  
Landscape Position ◽  
N Transformations ◽  
Legume Crop ◽  
No Till ◽  
Rainfall Patterns ◽  
A Site ◽  
Biological Nitrogen

Abstract PurposeExpected changes in rainfall patterns will affect the timing of N-mineralization and other N transformations, potentially promoting or suppressing biological nitrogen fixation (BNF). We test the hypotheses that BNF is more sensitive to changing rainfall patterns in summit vs. toeslope positions and in till vs. no-till consistent with patterns of soil texture and organic matter.MethodsAt a site in the upper Midwest USA, we measured soybean BNF 15N natural abundance at different landscape positions with and without supplemental rainfall and in till vs. no-till rainfall exclusion shelters to lengthen the dry periods between rainfall events. ResultsSoybean BNF was 41% higher at summit than toeslope positions, consistent with lower soil OM and coarser texture at summits. When precipitation was increased by 20%, BNF decreased at summit positions and was unaffected at toeslope positions. In a separate tillage experiment, with 3-week (but not 2-week) rainfall intervals, %BNF decreased 15% under conventional tillage and increased 14% under no-till. ConclusionsChanging rainfall patterns affected BNF differentially depending on landscape position and tillage in well-drained Alfisols. BNF was greater in summit than in toeslope positions and decreased with added rainfall. BNF under conventional tillage was more sensitive to longer rainfall intervals than was BNF under no-till. Models that incorporate these interactions will be better able to characterize legume crop performance and N use across landscapes and improve global estimates for BNF.

scholarly journals Biological Nitrogen Fixation and Productivity of Soybean in Maize-Soybean Intercrop under Tillage and Bradyrhizobium Inoculation on Alfisols of Northern Guinea Savanna, Nigeria

2020 ◽  
pp. 15-24
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Block Design ◽  
Conventional Tillage ◽  
N Fixation ◽  
Tillage Practices ◽  
Main Plot ◽  
Four Levels ◽  
Biological Nitrogen ◽  
Bradyrhizobium Inoculation

A field study was conducted in the 2011 cropping season to investigate the effect of tillage and bradyrhizobium inoculation of soybean on biological nitrogen fixation (BNF) and yield components in maize-soybean intercropping systems. Treatments comprised of two tillage practices (conventional tillage (CT) and reduced tillage (RT)) as the main plot and bradyrhizobium inoculation at four levels (inoculated sole soybean, inoculated soybean/maize intercrop, uninoculated sole soybean, and uninoculated soybean/maize intercrop) as sub-plot. The treatments were laid in a split-plot under a randomized complete block design with three replications. Results showed that BNF and nitrogen derived from atmospheric (Ndfa) were significantly higher under RT than CT by 4.18 and 0.10 %, respectively. The BNF was consistently higher in the maize-soybean intercropping system with soybean inoculated with bradyrhizobium than in the uninoculated. BNF was 28.0 % higher in inoculated sole soybean and 80.2 % higher in inoculated maize-soybean intercrop than the uninoculated sole and intercropping system. Similarly, grain yield was 31.0 % higher in the inoculated sole soybean than the uninoculated sole and 33.7 % higher in inoculated maize/soybean intercrop than in the uninoculated intercrop. Biomass yields under inoculatedsole soybean and maize-soybean intercrop, respectively, were significantly higher than in uninoculated sole soybean and maize-soybean intercrop by 30.99and 33.66% for inoculated and uninoculated soybean sole and 34.44 and 30.40 % for inoculated and uninoculated intercrop. The results demonstrated that integrating bradyrhizobium inoculants and tillage will improve N fixation and productivity in maize-soybeanbased intercropping systems in Alfisols of Northern savannah.

scholarly journals Functional analysis of multiple nifB genes of Paenibacillus strains in synthesis of Mo-, Fe- and V-nitrogenases

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qin Li ◽  
Haowei Zhang ◽  
Liqun Zhang ◽  
Sanfeng Chen
Keyword(s):  
Functional Analysis ◽  
Nitrogen Fixation ◽  
Gene Cluster ◽  
Biological Nitrogen Fixation ◽  
Deletion Analysis ◽  
Phylogeny Analysis ◽  
Biological Nitrogen

Abstract Background Biological nitrogen fixation is catalyzed by Mo-, V- and Fe-nitrogenases that are encoded by nif, vnf and anf genes, respectively. NifB is the key protein in synthesis of the cofactors of all nitrogenases. Most diazotrophic Paenibacillus strains have only one nifB gene located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV). But some Paenibacillus strains have multiple nifB genes and their functions are not known. Results A total of 138 nifB genes are found in the 116 diazotrophic Paenibacillus strains. Phylogeny analysis shows that these nifB genes fall into 4 classes: nifBI class including the genes (named as nifB1 genes) that are the first gene within the compact nif gene cluster, nifBII class including the genes (named as nifB2 genes) that are adjacent to anf or vnf genes, nifBIII class whose members are designated as nifB3 genes and nifBIV class whose members are named as nifB4 genes are scattered on genomes. Functional analysis by complementation of the ∆nifB mutant of P. polymyxa which has only one nifB gene has shown that both nifB1 and nifB2 are active in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Deletion analysis also has revealed that nifB1 of Paenibacillus sabinae T27 is involved in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Complementation of the P. polymyxa ∆nifBHDK mutant with the four reconstituted operons: nifB1anfHDGK, nifB2anfHDGK, nifB1vnfHDGK and nifB2vnfHDGK, has shown both that nifB1 and nifB2 were able to support synthesis of Fe- or V-nitrogenases. Transcriptional results obtained in the original Paenibacillus strains are consistent with the complementation results. Conclusions The multiple nifB genes of the diazotrophic Paenibacillus strains are divided into 4 classes. The nifB1 located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV) and the nifB2 genes being adjacent to nif or anf or vnf genes are active in synthesis of Mo-, Fe and V-nitrogenases, but nifB3 and nifB4 are not. The reconstituted anf system comprising 8 genes (nifBanfHDGK and nifXhesAnifV) and vnf system comprising 10 genes (nifBvnfHDGKEN and nifXhesAnifV) support synthesis of Fe-nitrogenase and V-nitrogenase in Paenibacillus background, respectively.

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