Abstract
In a greenhouse experiment potassium nitrate and urea isotopically labeled with 15N were applied to rice with different placements and in planted and unplanted compartments. The objective was to determine whether losses through the nitrification-denitrification sequence are influenced by rhizosphere effects, such as excretion of oxygen or microbial substrates from root surfaces. As expected, substantial losses of potassium nitrate-N were observed, and plant uptake of fertilizer N was very low except with a split-broadcast application. Banded and incorporated applications of urea were more efficient than broadcast. The highest uptake of fertilizer N measured was 50%. Oxidation-reduction potentials stabilized at values 8 to 15 mV lower in planted compartments than in adjacent ones containing no roots. Nitrogen loss data did not support the view that nitrification-denitrification was stimulated in the rhizosphere. The influence of growing plants was to decrease the magnitude of N losses from the system. Losses from broadcast urea application are indicative of some ammonia volatilization, although this was not measured directly.
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Claims 9
Claim · model-written summary
Potassium nitrate caused substantial nitrogen losses.
- Taxon
- rice
Oryza sativae1 - Treatment
- potassium nitratee0
- Outcome
- losses of potassium nitrate-Ne0
- Direction
- substantiale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“substantial losses of potassium nitrate-N were observed”
e1“were applied to rice”
Claim · model-written summary
Plant fertilizer nitrogen uptake was very low with potassium nitrate except split broadcast application.
- Taxon
- riceOryza sativae1
- Treatment
- potassium nitratee1
- Outcome
- plant uptake of fertilizer Ne0
- Direction
- very lowe0
- Qualifier
- except with a split-broadcast applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plant uptake of fertilizer N was very low except with a split-broadcast application”
e1“potassium nitrate and urea isotopically labeled with 15N were applied to rice”
Claim · model-written summary
Banded urea application was more efficient than broadcast.
- Taxon
- riceOryza sativae1
- Treatment
- Bandede0
- Outcome
- more efficiente0
- Direction
- more efficiente0
- Comparator
- broadcaste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Banded and incorporated applications of urea were more efficient than broadcast”
e1“were applied to rice”
Claim · model-written summary
Incorporated urea application was more efficient than broadcast.
- Taxon
- riceOryza sativae1
- Treatment
- incorporated applications of ureae0
- Outcome
- more efficiente0
- Direction
- more efficiente0
- Comparator
- broadcaste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Banded and incorporated applications of urea were more efficient than broadcast”
e1“were applied to rice”
Claim · model-written summary
The highest measured fertilizer nitrogen uptake was 50%.
- Taxon
- riceOryza sativae1
- Outcome
- uptake of fertilizer Ne0
- Direction
- higheste0
- Value
- 50%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest uptake of fertilizer N measured was 50%”
e1“were applied to rice”
Claim · model-written summary
Oxidation-reduction potentials were 8 to 15 mV lower in planted than root-free compartments.
- Taxon
- riceOryza sativae1
- Outcome
- Oxidation-reduction potentialse0
- Direction
- lowere0
- Value
- 8 to 15 mVe0
- Comparator
- adjacent ones containing no rootse0
- Setting
- planted compartmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxidation-reduction potentials stabilized at values 8 to 15 mV lower in planted compartments than in adjacent ones containing no roots”
e1“were applied to rice”
Claim · model-written summary
Nitrogen loss data did not support stimulated rhizosphere nitrification-denitrification.
- Taxon
- riceOryza sativae1
- Outcome
- nitrification-denitrification was stimulated in the rhizospheree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen loss data did not support the view that nitrification-denitrification was stimulated in the rhizosphere”
e1“were applied to rice”
Claim · model-written summary
Growing rice decreased system nitrogen losses.
- Taxon
- riceOryza sativae1
- Treatment
- growing plantse0
- Outcome
- magnitude of N losses from the systeme0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The influence of growing plants was to decrease the magnitude of N losses from the system”
e1“were applied to rice”
Claim · model-written summary
Broadcast urea losses suggested ammonia volatilization, although this was not directly measured.
- Taxon
- riceOryza sativae1
- Treatment
- broadcast urea applicatione0
- Outcome
- Lossese0
- Qualifier
- some ammonia volatilization, although this was not measured directlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Losses from broadcast urea application are indicative of some ammonia volatilization, although this was not measured directly”
e1“were applied to rice”