Abstract
Abstract Experiments were carried out on a vegetable field with Peking cabbage (Brassica pekinensis lour. rupr.), cabbage (Brassica chinensis var. oleifera makino and nemoto), green cabbage (Brassica chinensis L.), spinach (Spinacia oleracea L.), and rape (Brassica campestris L.) to study the effects of nitrogen (N) forms and rates, and phosphorus (P) fertilization on their growth and nitrate accumulation. The results indicated that application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach. Although N forms had no significantly different effect on yields, input of nitrate N fertilizer increased nitrate accumulation in vegetables much more than did ammonium N. Vegetable yields were not increased continuously with N rate, and an excess input of N fertilizer more or less reduced plant growth, leading to yield decline for the earlier harvests. This trend was also true for nitrate concentrations in some vegetables and at some sampling times. However, as a whole, nitrate concentrations in vegetables were positively correlated with N rates. As a result, addition of N fertilizer to soil was the major cause for vegetables increasing their nitrate contents. Effects of P fertilization on vegetable growth and nitrate accumulation were species and sampling-time dependant. By addition of P fertilizer, yields of green cabbage and rape were increased, while those of spinach and cabbage had no significant changes. The nitrate concentration was significantly decreased in green cabbage, but significantly increased in cabbage and rape by P fertilization at the second harvest. Different organs had different amount in nitrate accumulation, and it was found that nitrate concentrations were much higher in roots, stems, and petioles than in blades at any N rate.
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Claims 14
Claim · model-written summary
N fertilizers increased Peking cabbage yield and nitrate.
- Taxon
- Peking cabbagee0
- Treatment
- ammonium chloride, ammonium nitrate, sodium nitrate, and ureae0
- Outcome
- yields and nitrate concentrationse0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
Claim · model-written summary
N fertilizers increased spinach yield and nitrate.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- ammonium chloride, ammonium nitrate, sodium nitrate, and ureae0
- Outcome
- yields and nitrate concentrationse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
Claim · model-written summary
N forms did not significantly differ in yield.
Not reportedComparator
Verbatim
e0“N forms had no significantly different effect on yields”
t0“Vegetables”
Claim · model-written summary
Nitrate N produced more nitrate accumulation than ammonium N.
Verbatim
e0“input of nitrate N fertilizer increased nitrate accumulation in vegetables much more than did ammonium N”
Claim · model-written summary
Excess N reduced growth and early yield.
- Taxon
- Vegetablest0
- Treatment
- an excess input of N fertilizere0
- Outcome
- plant growthe0
- Direction
- reducede0
- Qualifier
- earlier harvestse0
Not reportedComparator
Verbatim
e0“an excess input of N fertilizer more or less reduced plant growth, leading to yield decline for the earlier harvests”
t0“Vegetables”
Claim · model-written summary
Nitrate concentrations correlated positively with N rates.
Verbatim
e0“nitrate concentrations in vegetables were positively correlated with N rates”
Claim · model-written summary
P increased green cabbage yields.
Not reportedComparator
Verbatim
e0“By addition of P fertilizer, yields of green cabbage and rape were increased”
Claim · model-written summary
P increased rape yields.
- Taxon
- rape
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napuse0 - Treatment
- P fertilizere0
- Outcome
- yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“By addition of P fertilizer, yields of green cabbage and rape were increased”
Claim · model-written summary
P did not significantly change spinach yields.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- P fertilizere2
- Outcome
- yieldse1
- Direction
- no significant changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“those of spinach and cabbage had no significant changes”
e1“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
e2“By addition of P fertilizer, yields of green cabbage and rape were increased”
t0“Phosphorus Fertilization”
Claim · model-written summary
P did not significantly change cabbage yields.
- Taxon
- cabbage
Brassica oleracea var. capitatae0 - Treatment
- P fertilizere2
- Outcome
- yieldse1
- Direction
- no significant changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“those of spinach and cabbage had no significant changes”
e1“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
e2“By addition of P fertilizer, yields of green cabbage and rape were increased”
t0“Phosphorus Fertilization”
Claim · model-written summary
P decreased nitrate in green cabbage.
Not reportedComparator
Verbatim
e0“nitrate concentration was significantly decreased in green cabbage”
e1“By addition of P fertilizer, yields of green cabbage and rape were increased”
t0“Phosphorus Fertilization”
Claim · model-written summary
P increased nitrate in cabbage.
- Taxon
- cabbageBrassica oleracea var. capitatae0
- Treatment
- P fertilizatione0
- Outcome
- nitrate concentratione1
- Direction
- increasede0
- Qualifier
- second harveste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly increased in cabbage and rape by P fertilization at the second harvest”
e1“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
t0“Nitrate Accumulation”
Claim · model-written summary
P increased nitrate in rape.
- Taxon
- rapeBrassica napuse0
- Treatment
- P fertilizatione0
- Outcome
- nitrate concentratione1
- Direction
- increasede0
- Qualifier
- second harveste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly increased in cabbage and rape by P fertilization at the second harvest”
e1“application of ammonium chloride, ammonium nitrate, sodium nitrate, and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach”
t0“Nitrate Accumulation”
Claim · model-written summary
Roots, stems and petioles accumulated more nitrate than blades.
Verbatim
e0“nitrate concentrations were much higher in roots, stems, and petioles than in blades at any N rate”
t0“Vegetables”
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