Abstract
Organic fertilization techniques have become an attractive alternative to conventional techniques, but there remains interest in their impact on rhizosphere ecology. This study was aimed at assessing the impacts of various organic fertilizer amendments on storage root yield, chemical, biochemical, and microbial factors in the rhizosphere ecosystem and the bacterial community composition in the rhizosphere ecosystem. Four sweetpotato cultivars (J6/66, NCC-58, TU Purple, and Whatley/Loretan) and four organic fertilizer treatments [poultry litter, Megabloom (fish protein), NPK, and an untreated control] were used in the study. The experiments were conducted as a randomized complete block design with a 4 × 4 factorial treatment arrangement and three replications. Fertilizer treatments were split-applied at the rate of 134–67–67 kg·ha −1 NPK equivalent based on soil test recommendations 1 and 4 weeks after planting as single bands 15 cm from the plants and organic amendments were calculated based on total N content. Rhizosphere soil samples were collected at harvest and analyzed for soil pH, soil organic carbon (SOC), bacterial 16S rDNA, and selected soil enzymes. Organic amendments did not affect storage root yield or percent dry matter but enhanced both the mass and number of US#1 storage roots. Rhizosphere pH varied depending on cultivar and cultivar response varied with pH and ranged from 6.1 to 6.8, whereas SOC was similar regardless of the amendment. The impact of fertilizers was evident as Megabloom (fish protein) treatment suppressed the relative abundance (RA) of nitrifiers ( Nitrosococcus and Nitrosomonadaceae ). Also, the rhizosphere of ‘Whatley/Loretan’ seemed to have been a beneficial habitat for populations of common nitrogen-fixing bacteria Bradyrhizobium elkanii , and Rhodospirillaceae sp. as their RA increased significantly in the rhizosphere. That bacteria associated with carbon and nitrogen cycling under aerobic conditions were found to be ubiquitous in the rhizosphere of sweetpotato, suggesting that certain amendments positively impacted the populations of nitrogen-cycling bacteria, thus making them a viable alternative to NPK when considering increasing or sustaining yield while promoting long-term soil health.
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Claims 8
Claim · model-written summary
Organic amendments did not affect sweetpotato storage root yield or dry matter.
- Taxon
- Sweetpotato
_Flower.jpg?width=60)
Ipomoea batatast0 - Treatment
- Organic amendmentse0
- Outcome
- storage root yield or percent dry mattere0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Flower.jpg?width=500)
Verbatim
e0“Organic amendments did not affect storage root yield or percent dry matter but enhanced both the mass and number of US#1 storage roots”
t0“Sweetpotato”
Claim · model-written summary
Organic amendments increased the mass and number of US#1 sweetpotato storage roots.
- Taxon
- SweetpotatoIpomoea batatast0
- Treatment
- Organic amendmentse0
- Outcome
- mass and number of US#1 storage rootse0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Organic amendments did not affect storage root yield or percent dry matter but enhanced both the mass and number of US#1 storage roots”
t0“Sweetpotato”
Claim · model-written summary
Sweetpotato rhizosphere pH varied by cultivar between 6.1 and 6.8.
- Taxon
- SweetpotatoIpomoea batatast0
- Material
- cultivare0
- Outcome
- Rhizosphere pHe0
- Direction
- variede0
- Value
- 6.1 to 6.8e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rhizosphere pH varied depending on cultivar and cultivar response varied with pH and ranged from 6.1 to 6.8”
t0“Sweetpotato”
Claim · model-written summary
Soil organic carbon was similar across sweetpotato fertilizer amendments.
- Taxon
- SweetpotatoIpomoea batatast0
- Treatment
- amendmente0
- Outcome
- SOCe0
- Direction
- similare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SOC was similar regardless of the amendment”
t0“Sweetpotato”
Claim · model-written summary
Megabloom suppressed the relative abundance of Nitrosococcus in the sweetpotato rhizosphere.
- Taxon
- SweetpotatoIpomoea batatast0
- Treatment
- Megabloom (fish protein) treatmente0
- Interactor
- NitrosococcusNitrosococcuse0other
- Outcome
- relative abundance (RA) of nitrifierse0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Megabloom (fish protein) treatment suppressed the relative abundance (RA) of nitrifiers ( Nitrosococcus and Nitrosomonadaceae )”
t0“Sweetpotato”
Claim · model-written summary
Megabloom suppressed the relative abundance of Nitrosomonadaceae in the sweetpotato rhizosphere.
- Taxon
- SweetpotatoIpomoea batatast0
- Treatment
- Megabloom (fish protein) treatmente0
- Interactor
- NitrosomonadaceaeNitrosomonadaceaee0other
- Outcome
- relative abundance (RA) of nitrifierse0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Megabloom (fish protein) treatment suppressed the relative abundance (RA) of nitrifiers ( Nitrosococcus and Nitrosomonadaceae )”
t0“Sweetpotato”
Claim · model-written summary
The relative abundance of Bradyrhizobium elkanii increased significantly in the Whatley/Loretan sweetpotato rhizosphere.
- Taxon
- SweetpotatoIpomoea batatast0
- Material
- Whatley/Loretane0
- Interactor
- Bradyrhizobium elkaniiBradyrhizobium elkaniie0symbiont
- Outcome
- RAe0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the rhizosphere of ‘Whatley/Loretan’ seemed to have been a beneficial habitat for populations of common nitrogen-fixing bacteria Bradyrhizobium elkanii , and Rhodospirillaceae sp. as their RA increased significantly in the rhizosphere”
t0“Sweetpotato”
Claim · model-written summary
The relative abundance of Rhodospirillaceae sp. increased significantly in the Whatley/Loretan sweetpotato rhizosphere.
- Taxon
- SweetpotatoIpomoea batatast0
- Material
- Whatley/Loretane0
- Interactor
- Rhodospirillaceae sp.Rhodospirillaceaee0symbiont
- Outcome
- RAe0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the rhizosphere of ‘Whatley/Loretan’ seemed to have been a beneficial habitat for populations of common nitrogen-fixing bacteria Bradyrhizobium elkanii , and Rhodospirillaceae sp. as their RA increased significantly in the rhizosphere”
t0“Sweetpotato”
The same questions in other papers
organic · yield · Ipomoea batatas (sweet potato)Positive and negative results
6 in the opposite direction
- positive
- positive
- positive
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See all 7 papers →other · soil: chemistry · Ipomoea batatas (sweet potato)Results agree
2 papers in the same direction as this paper
- no effect
- no effect
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.