scholarly journals Effect of Soil Textural Classes on the Biological Nitrogen Fixation by Bradyrhizobium Measured by 15N Dilution Analysis

2016 ◽  
Vol 13 (4) ◽  
pp. 734-744
Author(s):  
Baghdad Science Journal

The current study was conductedas a pot experiment to determine the effect of soil texture on biological nitrogen fixation (BNF) of six most efficient local isolates, specified, of Bradyrhizobium. Cowpea (Vignaunguiculata L.), as a legume host crop, was used as a host crop and 15N dilution analysis was used for accurate determination of the amount of N biologically fixed under experimental parameters specified. Soils used are clay loam, sandy clay loam and sandy loam. Biological Nitrogen Fixation (BNF), in different soil textural classes, was as in the following order: medium texture soil > heavy texture soil > light textured soil. Statistical analysis showed that there is a significant variation in BNF % among six Iraqi isolates in the three soil textural classes. There is a significant variation in the number of the nodules of the six Isolates in one soil texture. However, nodules number does not agree with the BNF% in the same soil for any isolates. Statistical analysis of the data showed that there were significant differences in plant dry weight among the soil textural classes all over local isolates used in this study. Data also showed that there were significant differences in dry weight under different isolates.

Author(s):  
Guilherme Vestena Cassol ◽  
Enio Marchesan ◽  
Joseph Harry Massey ◽  
Adroaldo Dias Robaina ◽  
Vinícius Severo Trivisiol ◽  
...  

Abstract: The objective of this work was to evaluate the effect of raised seedbeds associated with irrigation on the yield of soybean (Glycine max) rotated with rice (Oryza sativa) in lowland conditions in Southern Brazil. Field experiments were conducted in two crop seasons (2014/2015 and 2015/2016), with two planting systems (raised seedbed and flat planting) and two irrigation managements (irrigated and nonirrigated). Water use, biological nitrogen fixation, and yield were evaluated. The water used for raised seedbeds was 14% (151 m3 ha-1) and 27% (163 m3 ha-1) lower than that for flat planting in the first and second crop seasons, respectively. Irrigation increased nodule number per plant, nodule dry weight, and biological nitrogen fixation. The average grain yield of the raised seedbed system was 10% (529 kg ha-1) and 9% (362 kg ha-1) higher than that of flat planting in 2014/2015 and 2015/2016, respectively. Irrigation improved yield by 5% (203 kg ha-1) and 7% (265 kg ha-1) in each crop year. The use of raised seedbeds associated with irrigation improves the yield of soybean grown in rotation with rice in lowland in Southern Brazil.


Author(s):  
Omar Zennouhi ◽  
Abderrazak Rfaki ◽  
Mohamed El Mderssa ◽  
Jamal Ibijbijen ◽  
Laila Nassiri

Aims: The study aimed to evaluate the effect of inoculation by different rhizobacteria on Bituminaria bituminosa plants grown under greenhouse conditions. Study Design: An experimental study. Place and Duration of Study: The study was carried out at the Department of Biology (Environment and valorization of microbial and plant resources Unit), Faculty of Sciences, Moulay Ismail University-Meknes, from November 2019 to February 2020. Methodology: Eleven species and/or isolates belonging to Rhizobium genus are used to inoculate B. bituminosa plants; similarly, fresh and dry crushed nodules previously collected from B. bituminosa shrubs are tested. The bacterial inoculation effects are evaluated through the estimation of inoculated plants’ fresh and dry shoots weight, root dry weight, total nitrogen, nodules number and fresh weight in comparison to non-inoculated plants. The infectivity and efficiency of the bacteria and the biological nitrogen fixation are also evaluated. Results: The results enable us to select the infective strains on the basis of their positive effect on growth and total nitrogen, in order to produce inoculum for B. bituminosa. Efficiency and biological nitrogen fixation are also very high compared to the control, especially with the B.b1 strain isolated from Bituminaria bituminosa and identified as Rhizobium tibeticum. The fresh nodules crushing is also very efficient. as inoculant. Conclusion: The use of symbiotic complex as Rhizobium tibeticum – Bituminaria bituminosa or an inoculum produced from fresh nodules are an eco-friendly alternative for the design of sylvo-pastoral systems ensuring increased soil fertility, fodder productivity and sustainable agroforestry.


2016 ◽  
Vol 51 (7) ◽  
pp. 818-823 ◽  
Author(s):  
Vitor Camargo do Nascimento Junior ◽  
Cássio Egidio Cavenaghi Prete ◽  
Marco Antonio Nogueira

Abstract: The objective of this work was to assess the effects of 1-methylcyclopropene (1-MCP) on traits related with biological nitrogen fixation on 'BRS 268' soybean (Glycine max) subjected to water restriction. Plants were either exposed to drought between 32 (R2) and 47 (R3) days after sowing (DAS) or kept well-watered, in combination with exposure or not to 1-MCP. On the second day under drought (34 DAS), plants from both water conditions were exposed to 1-MCP in a hermetically sealed chamber for 15 hours. Control plants, dry or well-watered, that were not exposed to 1-MCP were kept in a separate chamber. At 36 (R2) and 47 (R3) DAS, shoot and root dry weights, leaf area index, number and dry weight of nodules, total ureides in sap, and N concentration in leaves were assessed. From 47 DAS on, extra plants were well watered until physiological maturity (R8) and assessed for yield components. Water restriction increased ureides in sap and reduced N in leaves in R2; reduced the number and mass of nodules, shoot dry weight, and leaf area index in R3; and reduced the number of pods and seed mass of plants not exposed to 1-MCP. However, when plants are exposed to 1-MCP, there is an attenuation of water restriction effects.


1988 ◽  
Vol 110 (1) ◽  
pp. 141-144 ◽  
Author(s):  
K. K. Dhingra ◽  
H. S. Sekhon ◽  
P. S. Sandhu ◽  
S. C. Bhandari

SummaryField experiments were conducted at the Punjab Agricultural University, Ludhiana from 1980–1 to 1984–5 to study the response of lentil genotypes to phosphorus application and Rhizobium inoculation. The number and dry weight of nodules increased consistently with increasing rates of application of phosphorus from 0 to 60 kg P2O5/ha. Nitrogenase activity of intact root nodules increased from 17 530 to 22 390 nmol/h per g dry weight of nodules with 20 kg P2O6/ha and to 27391 and 29170 nmol/h per g with 40 and 60 kg P2O5/ha, respectively. Rhizobium inoculation also increased nodulation, nitrogenase activity and grain yield. Interaction between phosphorus and Rhizobium inoculation was significant in 3 out of 5 years, indicating that the combination of Rhizobium and 20 kg P2O6/ha gave yield equivalent to 40 kg P2O6/ha without Rhizobium.


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