Abstract
Cowpea (Vigna unguiculata) is a major source of dietary protein and essential component of the cropping systems in semi-arid regions of Sub-Saharan Africa. However, yields are very low due to lack of improved cultivars, poor management practices and limited inputs use. The objectives of this study were to assess the effects of rhizobia inoculant and P on nodulation, N accumulation and yield of two cowpea cultivars in Mozambique. Field study was conducted in three contrasting environments during the 2013/2014 and 2014/2015 seasons using randomized complete block design with four replications. Treatments consisted of seed inoculation, application of 40 kg P2O5 ha-1, inoculation + P, and a non-inoculated control. The most probable number (MPN) technique was used to estimate the indigenous bradyrhizobia populations at the experimental sites. The rhizobia numbers at the sites varied from 5.27 x 102 to 1.07 x 103 cells g-1 soil. Inoculation increased nodule number by 34-76% and doubled nodule dry weight (78 to 160 mg plant-1). P application improved nodulation and interacted positively with the inoculant. Inoculation, P and inoculant + P increased shoot dry weight, and shoot and grain N content across locations but increases in number of pods plant-1, seeds pod-1 and 100-seed weight were not consistent among treatments across locations. Shoot N content was consistently high for the inoculated plants and also for the inoculated + P fertilized plants, whereas the non-inoculated control plants had the lowest tissue N content. P uptake in shoot ranged from 1.72-3.77 g kg-1 and was higher for plants that received P fertilizer alone. Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations with yields ranging from 1097 kg ha-1 for the non-inoculated control to 1674 kg ha-1 for the inoculant + P treatment. Grain protein concentration followed a similar trend as grain yield and ranged from 223-252 g kg-1 but a negative correlation between grain yield and protein concentration was observed. These results demonstrate the potential of improving cowpea grain yield and quality using inoculant, although the cost-benefit for using P at the current fertilizer price is not attractive.
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Claims 19
Claim · model-written summary
Indigenous bradyrhizobia abundance across sites ranged from 5.27 x 102 to 1.07 x 103 cells g-1 soil.
- Taxon
- Cowpea
Vigna unguiculatat0 - Interactor
- rhizobiae0symbiont
- Outcome
- rhizobia numberse0
- Value
- 5.27 x 102 to 1.07 x 103 cells g-1 soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The rhizobia numbers at the sites varied from 5.27 x 102 to 1.07 x 103 cells g-1 soil”
t0“Cowpea”
Claim · model-written summary
Inoculation increased cowpea nodule number by 34-76%.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Inoculatione0
- Outcome
- nodule numbere0
- Direction
- increasede0
- Value
- 34-76%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation increased nodule number by 34-76%”
t0“Cowpea”
Claim · model-written summary
Inoculation doubled nodule dry weight, reported as 78 to 160 mg plant-1.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Inoculatione1
- Outcome
- nodule dry weighte0
- Direction
- doublede0
- Value
- 78 to 160 mg plant-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“doubled nodule dry weight (78 to 160 mg plant-1)”
t0“Cowpea”
e1“Inoculation increased nodule number”
Claim · model-written summary
Phosphorus application improved cowpea nodulation.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- P applicatione0
- Outcome
- nodulatione0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P application improved nodulation”
t0“Cowpea”
Claim · model-written summary
Phosphorus application interacted positively with inoculant for nodulation.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- P applicatione0
- Interactor
- inoculante0symbiont
- Outcome
- nodulatione0
- Direction
- positivelye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P application improved nodulation and interacted positively with the inoculant”
t0“Cowpea”
Claim · model-written summary
Inoculation increased cowpea shoot dry weight and shoot and grain nitrogen content across locations.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Inoculatione0
- Outcome
- shoot dry weight, and shoot and grain N contente0
- Direction
- increasede0
- Qualifier
- across locationse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation, P and inoculant + P increased shoot dry weight, and shoot and grain N content across locations”
t0“Cowpea”
Claim · model-written summary
Phosphorus increased cowpea shoot dry weight and shoot and grain nitrogen content across locations.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Pe0
- Outcome
- shoot dry weight, and shoot and grain N contente0
- Direction
- increasede0
- Qualifier
- across locationse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation, P and inoculant + P increased shoot dry weight, and shoot and grain N content across locations”
t0“Cowpea”
Claim · model-written summary
Combined inoculant and phosphorus increased cowpea shoot dry weight and shoot and grain nitrogen content across locations.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- inoculant + Pe0
- Outcome
- shoot dry weight, and shoot and grain N contente0
- Direction
- increasede0
- Qualifier
- across locationse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation, P and inoculant + P increased shoot dry weight, and shoot and grain N content across locations”
t0“Cowpea”
Claim · model-written summary
Responses of pods per plant, seeds per pod and 100-seed weight were inconsistent across treatments and locations.
- Taxon
- CowpeaVigna unguiculatat0
- Outcome
- number of pods plant-1, seeds pod-1 and 100-seed weighte0
- Direction
- not consistente0
- Qualifier
- among treatments across locationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in number of pods plant-1, seeds pod-1 and 100-seed weight were not consistent among treatments across locations”
t0“Cowpea”
Claim · model-written summary
Inoculated plants had consistently high shoot nitrogen content compared with non-inoculated controls.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- inoculated plantse0
- Outcome
- Shoot N contente0
- Direction
- highe0
- Comparator
- non-inoculated control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shoot N content was consistently high for the inoculated plants and also for the inoculated + P fertilized plants, whereas the non-inoculated control plants had the lowest tissue N content”
t0“Cowpea”
Claim · model-written summary
Plants receiving inoculant and phosphorus had consistently high shoot nitrogen content compared with non-inoculated controls.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- inoculated + P fertilized plantse0
- Outcome
- Shoot N contente0
- Direction
- highe0
- Comparator
- non-inoculated control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shoot N content was consistently high for the inoculated plants and also for the inoculated + P fertilized plants, whereas the non-inoculated control plants had the lowest tissue N content”
t0“Cowpea”
Claim · model-written summary
Shoot phosphorus uptake ranged from 1.72-3.77 g kg-1 and was higher with phosphorus fertilizer alone.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- P fertilizer alonee0
- Outcome
- P uptake in shoote0
- Direction
- highere0
- Value
- 1.72-3.77 g kg-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P uptake in shoot ranged from 1.72-3.77 g kg-1 and was higher for plants that received P fertilizer alone”
t0“Cowpea”
Claim · model-written summary
Inoculation alone consistently increased cowpea grain yield across locations.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Inoculatione0
- Outcome
- cowpea grain yielde0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations”
t0“Cowpea”
Claim · model-written summary
Phosphorus alone consistently increased cowpea grain yield across locations.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Pe0
- Outcome
- cowpea grain yielde0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations”
t0“Cowpea”
Claim · model-written summary
Combined inoculant and phosphorus increased cowpea grain yield to 1674 kg ha-1, versus 1097 kg ha-1 for control.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- inoculant + P treatmente0
- Outcome
- cowpea grain yielde1
- Direction
- increasede1
- Value
- 1674 kg ha-1e0
- Qualifier
- 1097 kg ha-1e0
- Comparator
- non-inoculated controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yields ranging from 1097 kg ha-1 for the non-inoculated control to 1674 kg ha-1 for the inoculant + P treatment”
e1“Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations”
t0“Cowpea”
Claim · model-written summary
Grain protein concentration ranged from 223-252 g kg-1 and followed the yield trend.
- Taxon
- CowpeaVigna unguiculatat0
- Outcome
- Grain protein concentratione0
- Value
- 223-252 g kg-1e0
- Qualifier
- followed a similar trend as grain yielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain protein concentration followed a similar trend as grain yield and ranged from 223-252 g kg-1”
t0“Cowpea”
Claim · model-written summary
Grain yield was negatively correlated with protein concentration.
- Taxon
- CowpeaVigna unguiculatat0
- Outcome
- protein concentratione0
- Direction
- negativee0
- Comparator
- grain yielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a negative correlation between grain yield and protein concentration was observed”
t0“Cowpea”
Claim · model-written summary
The authors conclude that inoculant can improve cowpea yield and quality.
- Taxon
- cowpeaVigna unguiculatae0
- Outcome
- improving cowpea grain yield and quality using inoculante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These results demonstrate the potential of improving cowpea grain yield and quality using inoculant”
Claim · model-written summary
The authors conclude that phosphorus use is unattractive at the current fertilizer price.
- Taxon
- CowpeaVigna unguiculatat0
- Outcome
- cost-benefit for using P at the current fertilizer price is not attractivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the cost-benefit for using P at the current fertilizer price is not attractive”
t0“Cowpea”
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