Estimation of N<sub>2</sub>fixation in soybean and cowpea by using soil residual<sup>15</sup>N

Watanabe, Iwao; Chiu, Chih‐Yu; Yoshida, Tomio

doi:10.1080/00380768.1990.10416905

Cited by 6 publications

(4 citation statements)

References 15 publications

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“…Therefore, the growth of two crops before the ~SN dilution experiments are carried out is most suitable. As reported in the previous paper (Watanabe et al 1990), however, even one crop growth is acceptable.…”

Section: Discussionmentioning

confidence: 55%

“…The use of the microplots, however, was helpful in reducing the error associated with the spatial variability of N in soil. The former experiment (Watanabe et al 1990) showed that the variability of both N and lSN ratio in soil was markedly reduced after 1 month planting. The decline of the 'SN enrichment in the soil become stabilized resulting in a similar ~SN uptake pattern for both the N2-fixing crop and the reference crop.…”

Section: Discussionmentioning

confidence: 95%

“…The second sampling was performed at the pod filling (R5) stage, 67 DAS. Collection of plants and soil was performed as described in the former experiment (Watanabe et al 1990).…”

Section: Methodsmentioning

confidence: 99%

“…Also in the straw- amended soil, no change in the lSN abundance of the non-nodulating plants was found with time. In the previous study, it was reported that the half life of ~SN abundance in soil mineral N was about 100 days (Watanabe et al 1990).…”

Section: Lsn Abundancementioning

confidence: 95%

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Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods

Chiu

Watanabe

Yoshida

1990

Soil Science and Plant Nutrition

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The effect of different xsN labeled sources on the estimation of N2 fixation by soybean was investigated in the Philippines, using a non-nodulating isoline as a reference plant. The soil was placed in 1.5 • 1.5 m concrete plots. The labeled urea or rice straw was applied 1 month before soybean was sown in the soil which had received a labeled ammonium salt prior to the cultivation of two crops. Plots without these additions were also used. The N2 fixation during 0-36 days after sowing was negligible. The estimation of N2 fixed at 67 days of plant growth in the plots which received labeled urea or straw was not statistically different from the estimation in the plots with residual ~SN. The estimations based on both the N balance and ~SN dilution methods were not statistically different. The percentage of N derived from N2 was 41 and the quantity of N~ fixed was estimated at 33 kg N/ha. The least variation was found for the estimation of N2 fixation in the plots with residual ~SN. This fact is attributed to the stability of tSN in the soil, as the 15N abundance in soybeans in the plots with residual ~SN only showed the least variation among the replicates and did not change with the sampling time.

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Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 95%

“…The second sampling was performed at the pod filling (R5) stage, 67 DAS. Collection of plants and soil was performed as described in the former experiment (Watanabe et al 1990).…”

Section: Methodsmentioning

confidence: 99%

Section: Lsn Abundancementioning

confidence: 95%

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Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods

Chiu

Watanabe

Yoshida

1990

Soil Science and Plant Nutrition

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Field application of the 15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

Boddey

Oliveira

Alves

et al. 1995

Nitrogen Economy in Tropical Soils

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Field application of the15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

Boddey

Oliveira

Alves

et al. 1995

Fertilizer Research

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Estimation of N₂fixation in soybean and cowpea by using soil residual¹⁵N

Cited by 6 publications

References 15 publications

Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods

Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods

Field application of the 15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

Field application of the15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

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Estimation of N2fixation in soybean and cowpea by using soil residual15N

Cited by 6 publications

References 15 publications

Estimation of N2fixation of soybean by comparison of different15N labeling methods

Estimation of N2fixation of soybean by comparison of different15N labeling methods

Field application of the 15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

Field application of the15N isotope dilution technique for the reliable quantification of plant-associated biological nitrogen fixation

Contact Info

Product

Resources

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Estimation of N₂fixation in soybean and cowpea by using soil residual¹⁵N

Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods

Estimation of N₂fixation of soybean by comparison of different¹⁵N labeling methods