Abstract
African Crop Science Journal, Vol. 6. No. 2, pp. 171-178, 1998 Environmental constraints to nodulation and nitrogen fixation of Phaseolus vulgaris l. in Tanzania. II. Response to N and P fertilizers and inoculation with Rhizobium K.E. Giller , F. Amijee , S.J. Brodrick and O.T. Edje Code Number:CS98019 Sizes of Files: Text: 61K Graphics: No associated graphics files ABSTRACT Addition of P fertilizer (26 kg P ha-1) was shown to increase dramatically the number of root nodules and seed yields of Phaseolus vulgaris in experiments on farmers' fields in the West Usambara Mountains in northern Tanzania. Both nodulation and seed yields varied enormously between the different sites even where fertilizers were applied. Nitrogen fixation was measured in two of these experiments using the 15N isotope dilution method with a non-nodulating variety of P. vulgaris as a non-fixing reference plant. Without addition of P fertilizer the amount of N2 fixed was only 2-8 kg N ha-1 (25-27 %N derived from N2-fixation) and this was increased to 8-16 kg N ha-1 (48-51 %N derived from N2-fixation) with addition of 26 kg P ha-1. Inoculation with Rhizobium together with P addition increased nodulation and N2-fixation marginally above that with P alone but did not increase seed yields. Seed yields were only marginally improved by addition of P or N fertilizers at two sites in the Kilimanjaro/Meru region of northern Tanzania. At one of these sites (Kilacha) inoculation with P more than trebled the number of nodules but only marginally increased total N accumulation. Across all sites, addition of N fertilizer (45 kg N ha-1) increased yields slightly above those found with P alone. The need for further assessments of nodulation and N2-fixation under soil fertility conditions prevailing on farmers' fields is emphasised. Key Words: Inoculants, isotope dilution, N2-fixation, 15N, phosphorus, seed yield RÉSUMÉ L'addition de la fertilisation de P (26 kg P ha-1) a beaucoup augmenté le nombre de nodules racinaires ainsi que le rendement en graines de Phaseolus vulgaris en champs des fermiers dans la région montagneuse ouest d'Usambar au nord de la Tanzanie. La nodulation et le rendement en graines variaient amplement entre les différents sites traités à la fertilisation. La fixation de l'azote atmosphérique était mesurée dans deux de ces essais par la méthode de dilution de l'isotope 15N avec une variété non nodulante de P. vulgaris servant de témoin non fixateur. En l'absence de la fertilisation, seulement 2 à 8 kg N ha-1 soient 25-27%, dérivaient de la fixation de N atmosphérique tandis qu'avec l'addition de 26 kg P ha-1, la fixation azotée était élevée à 8-16 kg ha-1 soient 48-51%. La combinaison de Rhizobium avec le fertilisant P a légèrement augmenté la nodulation ainsi que la fixation de N par rapport au traitement de fertlisant P mais sans toutefois augmenter le rendement en graines. Le rendement en graines était légèrement amélioré par l'addition de P et de N dans les deux sites au sein de la région de Kilimanjaro/Meru au nord de la Tanzanie. Dans l'une de ces deux sites (Kilacha), le traitement au P a plus que tripplé le nombre de nodules tandis que la quantité d'azote total s'est légèrement augmentée par rapport au seul traitement de P. Le besoin de poursuivre ce genre de travail en vue d'examiner la nodulation et la fixation de N dans les conditions de sol qui prévalent en plein champ des fermiers est souligné. Mots Clés: Inoculants, dilution de l'isotope 15N, fixation de N2, phosphore, rendement en graines Copyright 1998 The African Crop Science Society
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Claims 11
Claim · model-written summary
P fertilizer addition increased the number of root nodules and seed yields of Phaseolus vulgaris.
- Taxon
- Phaseolus vulgaris
Phaseolus vulgarise0 - Treatment
- Addition of P fertilizer (26 kg P ha-1)e0
- Outcome
- the number of root nodules and seed yieldse0
- Direction
- increasee0
- Setting
- West Usambara Mountains in northern Tanzaniae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of P fertilizer (26 kg P ha-1) was shown to increase dramatically the number of root nodules and seed yields of Phaseolus vulgaris in experiments on farmers' fields in the West Usambara Mountains in northern Tanzania”
Claim · model-written summary
Nodulation and seed yields varied enormously between sites, even where fertilizers were applied.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Outcome
- nodulation and seed yieldse1
- Qualifier
- varied enormously between the different sitese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e1“Both nodulation and seed yields varied enormously between the different sites even where fertilizers were applied”
Claim · model-written summary
Adding 26 kg P ha-1 increased the amount of N2 fixed to 8-16 kg N ha-1.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- addition of 26 kg P ha-1e2
- Outcome
- the amount of N2 fixede2
- Direction
- increasede2
- Value
- 8-16 kg N ha-1e2
- Comparator
- Without addition of P fertilizere2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e2“Without addition of P fertilizer the amount of N2 fixed was only 2-8 kg N ha-1 (25-27 %N derived from N2-fixation) and this was increased to 8-16 kg N ha-1 (48-51 %N derived from N2-fixation) with addition of 26 kg P ha-1”
Claim · model-written summary
Adding 26 kg P ha-1 increased the share of N derived from N2 fixation to 48-51%.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- addition of 26 kg P ha-1e2
- Outcome
- %N derived from N2-fixatione2
- Direction
- increasede2
- Value
- 48-51 %e2
- Comparator
- Without addition of P fertilizere2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e2“Without addition of P fertilizer the amount of N2 fixed was only 2-8 kg N ha-1 (25-27 %N derived from N2-fixation) and this was increased to 8-16 kg N ha-1 (48-51 %N derived from N2-fixation) with addition of 26 kg P ha-1”
Claim · model-written summary
Rhizobium inoculation with P addition increased nodulation and N2 fixation marginally above P alone.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Inoculation with Rhizobium together with P additione3
- Outcome
- nodulation and N2-fixatione3
- Direction
- increasede3
- Qualifier
- marginallye3
- Comparator
- P alonee3
RhizobiumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e3“Inoculation with Rhizobium together with P addition increased nodulation and N2-fixation marginally above that with P alone but did not increase seed yields”
Claim · model-written summary
Rhizobium inoculation with P addition did not increase seed yield beyond P alone.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Inoculation with Rhizobium together with P additione3
- Outcome
- seed yieldse3
- Direction
- did not increasee3
- Comparator
- P alonee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e3“Inoculation with Rhizobium together with P addition increased nodulation and N2-fixation marginally above that with P alone but did not increase seed yields”
Claim · model-written summary
Inoculation with P more than trebled the number of nodules at Kilacha.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- inoculation with Pe4
- Outcome
- the number of nodulese4
- Direction
- more than treblede4
- Setting
- Kilachae4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e4“At one of these sites (Kilacha) inoculation with P more than trebled the number of nodules but only marginally increased total N accumulation”
Claim · model-written summary
Inoculation with P only marginally increased total N accumulation at Kilacha.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- inoculation with Pe4
- Outcome
- total N accumulatione4
- Direction
- increasede4
- Qualifier
- only marginallye4
- Setting
- Kilachae4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e4“At one of these sites (Kilacha) inoculation with P more than trebled the number of nodules but only marginally increased total N accumulation”
Claim · model-written summary
Addition of N fertilizer (45 kg N ha-1) increased yields slightly above P alone across all sites.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- addition of N fertilizer (45 kg N ha-1)e5
- Outcome
- yieldse5
- Direction
- increasede5
- Qualifier
- slightly abovee5
- Comparator
- P alonee5
- Setting
- Across all sitese5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e5“Across all sites, addition of N fertilizer (45 kg N ha-1) increased yields slightly above those found with P alone”
Claim · model-written summary
Addition of P or N fertilizers only marginally improved seed yields at two Kilimanjaro/Meru sites.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- addition of P or N fertilizerse6
- Outcome
- Seed yieldse6
- Direction
- improvede6
- Qualifier
- only marginallye6
- Setting
- Kilimanjaro/Meru region of northern Tanzaniae6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e6“Seed yields were only marginally improved by addition of P or N fertilizers at two sites in the Kilimanjaro/Meru region of northern Tanzania”
Claim · model-written summary
Further assessments of nodulation and N2 fixation under farmers field soil fertility conditions are needed.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Outcome
- further assessments of nodulation and N2-fixatione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Phaseolus vulgaris l. in Tanzania”
e7“The need for further assessments of nodulation and N2-fixation under soil fertility conditions prevailing on farmers' fields is emphasised”
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See all 156 papers →8 of 10 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.