Abstract
1. Urea containing less than 1% biuret was compared with ammonium nitrate in field experiments on barley, sugar beet, winter wheat and grassland, and with ammonium sulphate on potatoes, in various parts of Great Britain in the years 1957–61. 2. When broadcast on the seed-bed for barley at rates supplying 25–45 lb./acre of nitrogen in twenty-five experiments, urea and ammonium nitrate gave similar mean increases in grain yield on acid soils, while on alkaline soils urea gave smaller increases than ammonium nitrate. The relative effect of the two sources was similar on light and heavy soils and in the east and west of the country. 3. When broadcast on the seed-bed for sugar beet at 50–60 lb./acre of nitrogen in nineteen experiments, mostly on alkaline soils in eastern England, no difference was detected between the mean increases in yield of sugar and tops from urea and from ammonium nitrate. 4. In twenty-two experiments on potatoes urea gave slightly smaller mean increases in yield of tubers than those from ammonium sulphate when applied at 40–60 lb./acre of nitrogen, with a larger difference at 80–120 lb./acre. No influence of soil pH, soil texture, region of the country or method of application (broadcast on the flat or over the open ridges) was detected. 5. When broadcast as spring top dressings in seventeen experiments on winter wheat, mostly in western England and Scotland, at rates supplying 34–45 lb./acre of nitrogen, urea and ammonium nitrate gave similar mean increases in yield of grain.
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Claims 8
Claim · model-written summary
Urea and ammonium nitrate gave similar barley grain yield increases on acid soils.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Treatment
- ureae0
- Outcome
- grain yielde0
- Direction
- similar mean increasese0
- Comparator
- ammonium nitratee0
- Setting
- acid soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“urea and ammonium nitrate gave similar mean increases in grain yield on acid soils”
t0“barley”
Claim · model-written summary
Urea gave smaller barley grain yield increases than ammonium nitrate on alkaline soils.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- ureae0
- Outcome
- grain yielde1
- Direction
- smaller increasese0
- Comparator
- ammonium nitratee0
- Setting
- alkaline soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on alkaline soils urea gave smaller increases than ammonium nitrate.”
t0“barley, sugar beet”
e1“similar mean increases in grain yield on acid soils”
Claim · model-written summary
The relative barley fertilizer effect was similar across soil texture and regions.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- relative effect of the two sourcese0
- Direction
- similare0
- Qualifier
- east and west of the countrye0
- Setting
- light and heavy soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The relative effect of the two sources was similar on light and heavy soils and in the east and west of the country.”
t0“barley”
Claim · model-written summary
Urea and ammonium nitrate gave indistinguishable sugar beet sugar and tops yields.
- Taxon
- sugar beet
Beta vulgaris subsp. vulgarist0 - Treatment
- ureae0
- Outcome
- yield of sugar and topse0
- Direction
- no differencee0
- Comparator
- ammonium nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no difference was detected between the mean increases in yield of sugar and tops from urea and from ammonium nitrate.”
t0“sugar beet”
Claim · model-written summary
Urea gave slightly smaller potato tuber yield increases than ammonium sulphate at 40–60 lb./acre.
- Taxon
- potatoes
Solanum tuberosumt0 - Organ / stage
- tuberse0
- Treatment
- ureae0
- Outcome
- yield of tuberse0
- Direction
- slightly smallere0
- Value
- 40–60 lb./acree0
- Comparator
- ammonium sulphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“urea gave slightly smaller mean increases in yield of tubers than those from ammonium sulphate when applied at 40–60 lb./acre of nitrogen”
t0“potatoes”
Claim · model-written summary
The potato yield difference between urea and ammonium sulphate was larger at 80–120 lb./acre.
- Taxon
- potatoesSolanum tuberosumt0
- Treatment
- ureat0
- Outcome
- yield of tuberse1
- Direction
- larger differencee0
- Value
- 80–120 lb./acree0
- Comparator
- ammonium sulphatee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with a larger difference at 80–120 lb./acre.”
t0“urea as a fertilizer for barley, sugar beet, potatoes, winter wheat and grassland”
e1“urea gave slightly smaller mean increases in yield of tubers than those from ammonium sulphate when applied at 40–60 lb./acre of nitrogen”
Claim · model-written summary
Potato fertilizer response showed no detected influence of soil pH, texture, region or application method.
- Taxon
- potatoesSolanum tuberosumt0
- Outcome
- influencee0
- Direction
- No influencee0
- Setting
- soil pH, soil texture, region of the countrye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No influence of soil pH, soil texture, region of the country or method of application (broadcast on the flat or over the open ridges) was detected.”
t0“potatoes”
Claim · model-written summary
Urea and ammonium nitrate gave similar winter wheat grain yield increases.
- Taxon
- winter wheat
Triticum aestivumt0 - Treatment
- ureae0
- Outcome
- yield of graine0
- Direction
- similar mean increasese0
- Comparator
- ammonium nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“urea and ammonium nitrate gave similar mean increases in yield of grain.”
t0“winter wheat”
The same questions in other papers
nitrogen · yield · Solanum tuberosum (potato)Results differ
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- positive
- positive
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18 papers in the same direction as this paper · 142 reporting no difference from an alternative
- positive
- positive
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See all 161 papers →nitrogen · yield · Hordeum vulgare (barley)Positive and negative results
46 papers in the same direction as this paper · 252 in the opposite direction
- positive
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See all 299 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.