Abstract
An improved nutrient culture technique has been devised for producing vigorous soybean [ Glycine max (L.) Merr .] plants with urea as the only source of N. Of the sources of reduced‐N tested, (urea, amides, and ammonium salts of citrate, malate, fumarate, succinate, and sulfate), urea caused the least amount of plant injury. However, seedlings grew less when cultured with urea than with nitrate. The rapid decline of solution pH was likely responsible for the limited plant growth with the reduced N sources. Adjusting the solution pH daily did not alter the injurious effects. Addition of the Ca form of a carbpxy resin (Amberlite IR.C‐50, 50 g/liter) to the urea nutrient medium stabilized the pH and permitted plant growth equivalent to that of nitrate grown seedlings. In the presence of resin, plant growth with urea was superior to that with ammonium salts [e.g., (NH 4 ) 2 SO 4 ]. Growth of soybeans and wheat ( Triticum aestivum L .)was equivalent with urea (in the presence of resin) and nitrate while growth of peas ( Pisium sativum ) and velvet leaf ( Abutilon theophrasti ) was less with urea than with nitrate. All species grown on urea contained low amounts of nitrate (about 10% of nitrate grown controls) indicating that some interconversion of urea to nitrate occurs, although no nitrate was detectable in the nutrient solutions. In vivo nitrate reductase activity was low [less than 0.21 /μmoles NO 2 (g fresh wt‐hour) −1 ] with all species while in vitro activity ranged from 68% (soybean) to 11% (peas) of the activity of respective nitrate‐grown controls.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 16
Claim · model-written summary
Urea caused the least plant injury among tested reduced-nitrogen sources.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- ureae0
- Outcome
- plant injurye0
- Direction
- leaste0
- Comparator
- amides, and ammonium salts of citrate, malate, fumarate, succinate, and sulfatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Of the sources of reduced‐N tested, (urea, amides, and ammonium salts of citrate, malate, fumarate, succinate, and sulfate), urea caused the least amount of plant injury.”
Claim · model-written summary
Soybean seedlings grew less with urea than with nitrate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“seedlings grew less when cultured with urea than with nitrate.”
Claim · model-written summary
The decline in solution pH was considered a likely cause of limited growth with reduced nitrogen.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- reduced N sourcese0
- Outcome
- limited plant growthe0
- Qualifier
- rapid decline of solution pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“The rapid decline of solution pH was likely responsible for the limited plant growth with the reduced N sources.”
Claim · model-written summary
Daily pH adjustment did not alter injurious effects.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Adjusting the solution pH dailye0
- Outcome
- injurious effectse0
- Direction
- did not altere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Adjusting the solution pH daily did not alter the injurious effects.”
Claim · model-written summary
Adding calcium-form resin to the urea medium stabilized pH.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Ca form of a carbpxy resin (Amberlite IR.C‐50, 50 g/liter)e0
- Outcome
- pHe0
- Direction
- stabilizede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Addition of the Ca form of a carbpxy resin (Amberlite IR.C‐50, 50 g/liter) to the urea nutrient medium stabilized the pH”
Claim · model-written summary
Resin-buffered urea permitted growth equivalent to nitrate-grown soybean seedlings.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- urea nutrient mediume0
- Outcome
- plant growthe0
- Direction
- equivalente0
- Comparator
- nitrate grown seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Addition of the Ca form of a carbpxy resin (Amberlite IR.C‐50, 50 g/liter) to the urea nutrient medium stabilized the pH and permitted plant growth equivalent to that of nitrate grown seedlings.”
Claim · model-written summary
With resin, soybean growth on urea exceeded growth on ammonium salts.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- ureae0
- Outcome
- plant growthe0
- Direction
- superiore0
- Qualifier
- In the presence of resine0
- Comparator
- ammonium saltse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“In the presence of resin, plant growth with urea was superior to that with ammonium salts [e.g., (NH 4 ) 2 SO 4 ].”
Claim · model-written summary
Soybean growth was equivalent with resin-buffered urea and nitrate.
- Taxon
- soybeansGlycine maxe0
- Treatment
- urea (in the presence of resin)e0
- Outcome
- Growthe0
- Direction
- equivalente0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of soybeans and wheat ( Triticum aestivum L .)was equivalent with urea (in the presence of resin) and nitrate”
Claim · model-written summary
Wheat growth was equivalent with resin-buffered urea and nitrate.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- urea (in the presence of resin)e0
- Outcome
- Growthe0
- Direction
- equivalente0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of soybeans and wheat ( Triticum aestivum L .)was equivalent with urea (in the presence of resin) and nitrate”
Claim · model-written summary
Pea growth was lower with urea than nitrate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“growth of peas ( Pisium sativum ) and velvet leaf ( Abutilon theophrasti ) was less with urea than with nitrate.”
Claim · model-written summary
Velvet leaf growth was lower with urea than nitrate.
- Taxon
- velvet leaf
Abutilon theophrastie0 - Treatment
- ureae0
- Outcome
- growthe0
- Direction
- lesse0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“growth of peas ( Pisium sativum ) and velvet leaf ( Abutilon theophrasti ) was less with urea than with nitrate.”
Claim · model-written summary
Urea-grown species contained nitrate at about 10% of the nitrate-grown control amount.
Verbatim
e0“All species grown on urea contained low amounts of nitrate (about 10% of nitrate grown controls)”
Claim · model-written summary
No nitrate was detectable in nutrient solutions.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- no nitrate was detectable in the nutrient solutionse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“no nitrate was detectable in the nutrient solutions.”
Claim · model-written summary
In vivo nitrate reductase activity was low across all species.
Verbatim
e0“In vivo nitrate reductase activity was low [less than 0.21 /μmoles NO 2 (g fresh wt‐hour) −1 ] with all species”
Claim · model-written summary
In vitro nitrate reductase activity in soybean was 68% of nitrate-grown controls.
- Taxon
- soybeanGlycine maxe0
- Outcome
- in vitro activitye0
- Value
- 68%e0
- Comparator
- nitrate‐grown controlse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in vitro activity ranged from 68% (soybean) to 11% (peas) of the activity of respective nitrate‐grown controls.”
Claim · model-written summary
In vitro nitrate reductase activity in peas was 11% of nitrate-grown controls.
- Taxon
- peas
Lathyrus oleraceuse0 - Outcome
- in vitro activitye0
- Value
- 11%e0
- Comparator
- nitrate‐grown controlse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in vitro activity ranged from 68% (soybean) to 11% (peas) of the activity of respective nitrate‐grown controls.”
The same questions in other papers
calcium atom · soil: chemistry · Glycine max (soybean)Results agree
1 paper in the same direction as this paper
- positive
nitrogen · crop injury · Glycine max (soybean)Positive and negative results
2 in the opposite direction
- negative
- negative
nitrogen · growth · Lathyrus oleraceus (pea)Positive and negative results
15 papers in the same direction as this paper · 19 in the opposite direction
- positive
- positive
- positive
31 papers more in this group
See all 35 papers →in vitro · growth · Glycine max (soybean)Positive and negative results
37 papers in the same direction as this paper · 14 in the opposite direction · 1 reporting no difference from an alternative
- negative
- negative
- negative
49 papers more in this group
See all 53 papers →nitrogen · growth · Glycine max (soybean)Positive and negative results
116 papers in the same direction as this paper · 34 in the opposite direction · 2 reporting no difference from an alternative
- no effect
- negative
- no effect
149 papers more in this group
See all 153 papers →nitrogen · growth · Triticum aestivum (wheat)Positive and negative results
124 papers in the same direction as this paper · 426 reporting no difference from an alternative
- positive
- positive
- positive
547 papers more in this group
See all 551 papers →nitrogen · growth · Abutilon theophrasti (velvetleaf)Results agree
3 papers in the same direction as this paper
- negative
- negative
- negative
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.