Abstract
In field trials on Kanapaha fine sand at Gainesville, Florida in 1970-2, grain sorghum cv. Bird-Go and BR-64 was given 78, 157 or 313 kg N/ha as sulphur-coated urea (SCU), ammonium nitrate or urea or 470 kg N/ha as SCU. An unfertilized winter crop of rye or ryegrass was used to measure residual N each season. Sorghum grain and silage yields were not significantly affected by either N source or date of application of N (all at sowing or part at sowing and part as side-dressing); average annual grain yield for all application rates and dates was 4.31 t/ha for ammonium nitrate, 4.38 t for SCU and 4.44 t for urea. Increasing the N rate above 157 kg/ha did not significantly increase yields and the 470 kg N/ha rate was toxic to seedlings. SCU furnished more residual N to winter rye and ryegrass than did the other sources at high N rates but this seemed to be of little practical value at normal rates of applied N. Drastic reductions were noted in the pH and the Ca, Mg and K contents of the soil at the end of the 3-year period for the 470 kg N/ha rate of SCU
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Claims 5
Claim · model-written summary
Nitrogen source and timing did not significantly affect sorghum grain and silage yield.
- Treatment
- N source or date of application of Ne0
- Outcome
- grain and silage yieldse0
- Direction
- not significantly affectede0
SorghumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sorghum grain and silage yields were not significantly affected by either N source or date of application of N (all at sowing or part at sowing and part as side-dressing)”
Claim · model-written summary
Increasing nitrogen above 157 kg/ha did not significantly raise yield.
- Taxon
- grain sorghum
Sorghum bicolort0 - Treatment
- N rate above 157 kg/hae0
- Outcome
- yieldse0
- Direction
- did not significantly increasee0
- Comparator
- 157 kg/hae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the N rate above 157 kg/ha did not significantly increase yields”
t0“grain sorghum”
Claim · model-written summary
SCU at 470 kg N/ha was toxic to seedlings.
- Taxon
- grain sorghumSorghum bicolort0
- Treatment
- 470 kg N/hae0
- Outcome
- toxic to seedlingse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the 470 kg N/ha rate was toxic to seedlings”
t0“grain sorghum”
Claim · model-written summary
At high rates SCU left more residual nitrogen for winter rye and ryegrass than other N sources.
- Taxon
- rye
Secale cerealee0 - Treatment
- SCUe0
- Outcome
- residual Ne0
- Direction
- moree0
- Comparator
- the other sourcese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SCU furnished more residual N to winter rye and ryegrass than did the other sources at high N rates”
Claim · model-written summary
High rate SCU reduced soil pH and Ca, Mg and K content over three years.
- Taxon
- grain sorghumSorghum bicolort0
- Treatment
- 470 kg N/ha rate of SCUe0
- Outcome
- pH and the Ca, Mg and K contents of the soile0
- Direction
- reductionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drastic reductions were noted in the pH and the Ca, Mg and K contents of the soil at the end of the 3-year period for the 470 kg N/ha rate of SCU”
t0“grain sorghum”
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