Abstract
In order to investigate the effect of organic and inorganic nutrient sources on sweet potato tuber yield, we carried out a series of experiments at Hobu, Morobe Province, PNG. In the first experiment, plots were planted with Piper aduncum, Gliricidia sepium and Imperata cylindrica. After one year, these plants were slashed and sweet potato was planted. Sweet potato yield was lowest in plots with previous gliricidia, but there were no differences in yield between previous piper and imperata. In the second season, there was no significant difference in sweet potato yields between the plots. The second experiment consisted of a factorial fertiliser trial with four levels of nitrogen (0, 50, 100 or 150 kilograms per hectare) and two levels of potassium (0 or 50 kilograms per hectare). Nitrogen fertilisers increased tuber yield in the first season, but depressed tuber yields in the second and third seasons. Nitrogen fertiliser significantly increased vine yields in all three seasons. Potassium fertiliser had no effect on marketable tuber yield, but increased nonmarketable tuber yields. The third experiment compared nitrogen provided by inorganic fertiliser or by poultry litter at four rates (0, 50, 100 or 150 kilograms per hectare). No difference was found between the inorganic fertiliser and poultry litter, and highest yields were found at 100 kilograms of nitrogen per hectare. In the second season, no significant response to nitrogen was observed. This research indicates that sweet potato yield can be significantly
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Claims 11
Claim · model-written summary
Sweet potato yield was lowest after gliricidia.
- Taxon
- Sweet potato
_Flower.jpg?width=60)
Ipomoea batatase0 - Treatment
- previous gliricidiae0
- Outcome
- yielde0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Flower.jpg?width=500)
Verbatim
e0“Sweet potato yield was lowest in plots with previous gliricidia”
Claim · model-written summary
Yield did not differ after piper versus imperata.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- previous pipere0
- Outcome
- yielde0
- Direction
- no differencese0
- Comparator
- imperatae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there were no differences in yield between previous piper and imperata”
t0“sweet potato”
Claim · model-written summary
The second season showed no significant yield difference among preceding-plant plots.
- Taxon
- sweet potatoIpomoea batatase0
- Treatment
- plotse0
- Outcome
- yieldse0
- Direction
- no significant differencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the second season, there was no significant difference in sweet potato yields between the plots.”
Claim · model-written summary
Nitrogen fertilizer increased first-season tuber yield.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- Nitrogen fertiliserse0
- Outcome
- tuber yielde0
- Direction
- increasede0
- Qualifier
- first seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilisers increased tuber yield in the first season”
t0“sweet potato”
Claim · model-written summary
Nitrogen fertilizer depressed tuber yield in the second and third seasons.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- Nitrogen fertiliserse0
- Outcome
- tuber yieldse0
- Direction
- depressede0
- Qualifier
- second and third seasonse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilisers increased tuber yield in the first season, but depressed tuber yields in the second and third seasons.”
t0“sweet potato”
Claim · model-written summary
Nitrogen fertilizer significantly increased vine yields in all three seasons.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- Nitrogen fertilisere0
- Outcome
- vine yieldse0
- Direction
- increasede0
- Qualifier
- all three seasonse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertiliser significantly increased vine yields in all three seasons.”
t0“sweet potato”
Claim · model-written summary
Potassium fertilizer had no effect on marketable tuber yield.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- Potassium fertilisere0
- Outcome
- marketable tuber yielde0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Potassium fertiliser had no effect on marketable tuber yield”
t0“sweet potato”
Claim · model-written summary
Potassium fertilizer increased nonmarketable tuber yield.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- Potassium fertilisere0
- Outcome
- nonmarketable tuber yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Potassium fertiliser had no effect on marketable tuber yield, but increased nonmarketable tuber yields.”
t0“sweet potato”
Claim · model-written summary
Inorganic fertilizer and poultry litter gave no different yield response.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- inorganic fertilisere0
- Outcome
- No differencee0
- Direction
- No differencee0
- Comparator
- poultry littere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No difference was found between the inorganic fertiliser and poultry litter”
t0“sweet potato”
Claim · model-written summary
The highest yields occurred at 100 kilograms of nitrogen per hectare.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- 100 kilograms of nitrogen per hectaree0
- Outcome
- yieldse0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“highest yields were found at 100 kilograms of nitrogen per hectare”
t0“sweet potato”
Claim · model-written summary
The second season showed no significant response to nitrogen.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- nitrogene0
- Outcome
- response to nitrogene0
- Direction
- no significant responsee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the second season, no significant response to nitrogen was observed.”
t0“sweet potato”
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See all 145 papers →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.