Effect of successive cutting on nodulation and nitrogen fixation of Leucaena leucocephala using 15N dilution and the difference methods

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.

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Rhizosphere populations of Rhizobium strains and nodulation of Leucaena leucocephala

Australian Journal of Experimental Agriculture ◽

10.1071/ea9820293 ◽

1982 ◽

Vol 22 (117) ◽

pp. 293 ◽

Cited By ~ 4

Author(s):

HVA Bushby

Keyword(s):

Nitrogen Fixation ◽

Sandy Soil ◽

Leucaena Leucocephala ◽

Field Experiments ◽

Podzolic Soil ◽

Population Level ◽

Nodule Formation ◽

Seed Inoculation ◽

Rhizobium Strains ◽

Prairie Soil

Populations of two Rhizobium strains (NGR8 and CB81) in the rhizosphere of Leucaena leucocephala were estimated in field experiments with varying levels of antibiotically marked strains as seed inoculation treatments. The population level varied with soil type and strain of Rhizobium. Multiplication in the rhizosphere was very slow in a prairie soil but was more rapid in a sandy podzolic soil and nodulation was three weeks earlier in the sandy soil than in the prairie soil. Survival of these two strains in soil stored in the laboratory also suggested that they (especially NGR8) were not well suited to the prairie soil. Nodule representation of strain CB81 on the prairie soil decreased from 100% three months after sowing to between 12% and 16% two years after sowing. The results suggest that on this soil indigenous rhizobia form effective nitrogen fixing associations with Leucaena leucocephala and that any improvement in nitrogen fixation will require strains of Rhizobium that are more effective than the indigenous strains and better competitors for nodule formation.

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Increase in Milk Yield from Cows through Improvement of Forage Production Using the N2-Fixing Legume Leucaena leucocephala in a Silvopastoral System

Animals ◽

10.3390/ani10040734 ◽

2020 ◽

Vol 10 (4) ◽

pp. 734

Author(s):

Lucero Sarabia-Salgado ◽

Francisco Solorio-Sánchez ◽

Luis Ramírez-Avilés ◽

Bruno José Rodrigues Alves ◽

Juan Ku-Vera ◽

...

Keyword(s):

Nitrogen Fixation ◽

Milk Production ◽

Leucaena Leucocephala ◽

Crude Protein ◽

Forage Yield ◽

Silvopastoral System ◽

Forage Production ◽

N Transfer ◽

Randomized Design ◽

Completely Randomized Design

The objective was to evaluate milk production, N2-fixation and N transfer, forage yield and composition (under two cutting intervals) in a silvopastoral system (SPS) with Leucaena leucocephala-Megathyrsus maximus and M. maximus-monoculture (MMM) with crossbred cows in a completely randomized design. Forage yield in the SPS was 6490 and 6907 kg DM ha−1 for cutting intervals (CI) of 35 and 50 days. Forage yield for the MMM was 7284 and 10,843 kg DM ha−1, and forage crude protein (CP) was 29.0% and 26.1% for L. leucocephala, harvested at 35 and 50 days, respectively. CP for the associated M. maximus was 9.9% and 7.8% for CI 35 and 50 days, respectively, and for MMM was 7.4% and 8.4%, harvested at 35 and 50 days. Milk production was 4.7 kg cow−1 day−1 for cows grazing MMM and 7.4 kg cow−1 day−1 under SPS. Nitrogen fixation in L. leucocephala (%Ndfa) was estimated to be 89% and 95%, at 35 and 50 days, with an N2 transfer to the associated grass of 34.3% and 52.9%. SPS has the potential to fix and transfer important amounts of N2 to the associated grass, and increase forage CP content and milk production.

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Interdiffusion in many dimensions: mathematical models, numerical simulations and experiment

Mathematics and Mechanics of Solids ◽

10.1177/1081286520923376 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2178-2198

Author(s):

Lucjan Sapa ◽

Bogusław Bożek ◽

Katarzyna Tkacz–Śmiech ◽

Marek Zajusz ◽

Marek Danielewski

Keyword(s):

Finite Difference Methods ◽

Mass Conservation ◽

Three Dimensions ◽

Uniqueness Of Solutions ◽

Strongly Coupled ◽

Nonlinear Parabolic ◽

Implicit Difference Schemes ◽

Coupled Boundary Conditions ◽

Difference Methods ◽

The Difference

Over the last two decades, there have been tremendous advances in the computation of diffusion and today many key properties of materials can be accurately predicted by modelling and simulations. In this paper, we present, for the first time, comprehensive studies of interdiffusion in three dimensions, a model, simulations and experiment. The model follows from the local mass conservation with Vegard’s rule and is combined with Darken’s bi-velocity method. The approach is expressed using the nonlinear parabolic–elliptic system of strongly coupled differential equations with initial and nonlinear coupled boundary conditions. Implicit finite difference methods, preserving Vegard’s rule, are generated by some linearization and splitting ideas, in one- and two-dimensional cases. The theorems on the existence and uniqueness of solutions of the implicit difference schemes and the consistency of the difference methods are studied. The numerical results are compared with experimental data for a ternary Fe-Co-Ni system. A good agreement of both sets is revealed, which confirms the strength of the method.

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A New Class of Difference Methods with Intrinsic Parallelism for Burgers–Fisher Equation

Mathematical Problems in Engineering ◽

10.1155/2020/9162563 ◽

2020 ◽

Vol 2020 ◽

pp. 1-17

Author(s):

Yueyue Pan ◽

Lifei Wu ◽

Xiaozhong Yang

Keyword(s):

Stability And Convergence ◽

Fisher Equation ◽

Spatial Accuracy ◽

New Class ◽

Intrinsic Parallelism ◽

Parallel Difference ◽

Difference Methods ◽

Explicit And Implicit Schemes ◽

The Difference ◽

Time Accuracy

This paper proposes a new class of difference methods with intrinsic parallelism for solving the Burgers–Fisher equation. A new class of parallel difference schemes of pure alternating segment explicit-implicit (PASE-I) and pure alternating segment implicit-explicit (PASI-E) are constructed by taking simple classical explicit and implicit schemes, combined with the alternating segment technique. The existence, uniqueness, linear absolute stability, and convergence for the solutions of PASE-I and PASI-E schemes are well illustrated. Both theoretical analysis and numerical experiments show that PASE-I and PASI-E schemes are linearly absolute stable, with 2-order time accuracy and 2-order spatial accuracy. Compared with the implicit scheme and the Crank–Nicolson (C-N) scheme, the computational efficiency of the PASE-I (PASI-E) scheme is greatly improved. The PASE-I and PASI-E schemes have obvious parallel computing properties, which show that the difference methods with intrinsic parallelism in this paper are feasible to solve the Burgers–Fisher equation.

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15N Dilution technique of assessing the contribution of nitrogen fixation to rice plant

Soil Science & Plant Nutrition ◽

10.1080/00380768.1983.10432414 ◽

1983 ◽

Vol 29 (2) ◽

pp. 123-131 ◽

Cited By ~ 20

Author(s):

Wilbur Ventura ◽

Iwao Watanabe

Keyword(s):

Nitrogen Fixation ◽

Rice Plant ◽

Dilution Technique ◽

15N Dilution ◽

15N Dilution Technique

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The effects of ozone and nitrogen fertilizer on tall fescue, ladino clover, and a fescue–clover mixture. II. Nitrogen content and nitrogen fixation

Canadian Journal of Botany ◽

10.1139/b83-234 ◽

1983 ◽

Vol 61 (8) ◽

pp. 2159-2168 ◽

Cited By ~ 8

Author(s):

Ruben A. Montes ◽

Udo Blum ◽

Allen S. Heagle ◽

Richard J. Volk

Keyword(s):

Nitrogen Fixation ◽

Tall Fescue ◽

Difference Method ◽

Festuca Arundinacea ◽

Ambient Air ◽

N Fertilization ◽

Dilution Method ◽

N Fixation ◽

The Difference ◽

N Dilution Method

The effects of chronic doses of ozone (O3) and rates of nitrogen (N) fertilizer on N content of ladino clover (Trifolium repens L. cv. Tillman) and tall fescue (Festuca arundinacea Schreb. cv. Kentucky 31), and on N fixation by the clover were studied during the 1979 growing season. Plants of the two species were grown (i) in pots separately, (ii) together in open-top field chambers, and (iii) in ambient air plots. Mean 7 h/day (0930–1630 h eastern daylight time) O3 concentrations for the study period were 0.03 ppm in charcoal-filtered air chambers, 0.05 ppm in nonfiltered air chambers, 0.08 ppm in nonfiltered air chambers with O3 added for 7 h/day, and 0.05 ppm in ambient air. Shoot N concentrations (milligrams per gram dry weight) for clover and fescue were not modified by O3 exposures nor by N fertilization. Higher ozone levels led to reduced system N fixation (milligrams N per pot) by clover grown separately or together with fescue. Nitrogen fixation by ladino clover grown with tall fescue was 1.4 times greater than that by the clover grown alone. Nitrogen fixation by clover as estimated by the difference method was approximately 45% lower than N fixation as estimated by the 15N dilution method. Nitrogen fixation estimated by the difference method declined significantly with increasing N fertilization. This was not the case for N fixation estimated by the 15N dilution method.

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