Abstract
Applying nitrogen (N) to increase alfalfa (Medicago sativa L.) yield is a general practice in China that has caused serious weed infestation problems. Our objective was to determine the effect of N fertilizer and seeding rate on yields of alfalfa and weeds. The effects of four N fertilizer gradients (0, 50, 100, and 150 kg N hm -2 ) and five alfalfa seeding rates (0, 5, 7.5, 10, and 15 kg hm -2 ) were examined on dry matter of alfalfa and weeds using a three-year in situ controlled trial. The results showed: There were no significant differences among N fertilizer (N) for dry matter of alfalfa (DMA) during three years. Dry matter of grassy weeds (DMGW) and broadleaf weeds (DMBW) were significantly increased with the N fertilizer gradient in the seeding year. DMA was significantly increased with the seeding rates gradient in both 2012 and 2013. DMGW and DMBW were significantly decreased with the seeding rates gradient in all three years. Interactions between N fertilizer and seeding rates on DMA and DMBW in 2012 and DMGW and DMT in 2013 are significant (p<0.05). Although the study demonstrated that increasing seeding rate can suppress weed invasions, N fertilizer facilitated them.
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Claims 10
Claim · model-written summary
N fertilizer had no significant effect on alfalfa dry matter over three years.
- Taxon
- Alfalfa
Medicago sativat0 - Treatment
- N fertilizere1
- Outcome
- dry matter of alfalfa (DMA)e1
- Direction
- no_changeinferrede1
- Qualifier
- during three yearse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e1“The results showed: There were no significant differences among N fertilizer (N) for dry matter of alfalfa (DMA) during three years”
Claim · model-written summary
N fertilizer gradient significantly increased grassy weed dry matter in the seeding year.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- N fertilizer gradiente2
- Interactor
- grassy weedse2weed
- Outcome
- Dry matter of grassy weeds (DMGW)e2
- Direction
- increasede2
- Qualifier
- in the seeding yeare2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e2“Dry matter of grassy weeds (DMGW) and broadleaf weeds (DMBW) were significantly increased with the N fertilizer gradient in the seeding year”
Claim · model-written summary
N fertilizer gradient significantly increased broadleaf weed dry matter in the seeding year.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- N fertilizer gradiente2
- Interactor
- broadleaf weedse2weed
- Outcome
- broadleaf weeds (DMBW)e2
- Direction
- increasede2
- Qualifier
- in the seeding yeare2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e2“Dry matter of grassy weeds (DMGW) and broadleaf weeds (DMBW) were significantly increased with the N fertilizer gradient in the seeding year”
Claim · model-written summary
Seeding rate gradient significantly increased alfalfa dry matter in 2012 and 2013.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- seeding rates gradiente3
- Outcome
- DMAe3
- Direction
- increasede3
- Qualifier
- in both 2012 and 2013e3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e3“DMA was significantly increased with the seeding rates gradient in both 2012 and 2013”
Claim · model-written summary
Seeding rate gradient significantly decreased grassy weed dry matter in all three years.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- seeding rates gradiente4
- Interactor
- grassy weedse2weed
- Outcome
- DMGWe4
- Direction
- decreasede4
- Qualifier
- in all three yearse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e2“Dry matter of grassy weeds (DMGW) and broadleaf weeds (DMBW) were significantly increased with the N fertilizer gradient in the seeding year”
e4“DMGW and DMBW were significantly decreased with the seeding rates gradient in all three years”
Claim · model-written summary
Seeding rate gradient significantly decreased broadleaf weed dry matter in all three years.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- seeding rates gradiente4
- Interactor
- broadleaf weedse2weed
- Outcome
- DMBWe4
- Direction
- decreasede4
- Qualifier
- in all three yearse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e2“Dry matter of grassy weeds (DMGW) and broadleaf weeds (DMBW) were significantly increased with the N fertilizer gradient in the seeding year”
e4“DMGW and DMBW were significantly decreased with the seeding rates gradient in all three years”
Claim · model-written summary
N fertilizer and seeding rate interacted significantly for alfalfa and broadleaf weed dry matter in 2012.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- N fertilizer and seeding ratese5
- Outcome
- DMA and DMBWe5
- Qualifier
- in 2012e5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e5“Interactions between N fertilizer and seeding rates on DMA and DMBW in 2012 and DMGW and DMT in 2013 are significant (p<0.05)”
Claim · model-written summary
N fertilizer and seeding rate interacted significantly for grassy weed and total dry matter in 2013.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- N fertilizer and seeding ratese5
- Outcome
- DMGW and DMTe5
- Qualifier
- in 2013e5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e5“Interactions between N fertilizer and seeding rates on DMA and DMBW in 2012 and DMGW and DMT in 2013 are significant (p<0.05)”
Claim · model-written summary
Increasing seeding rate suppressed weed invasions.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- increasing seeding ratee6
- Interactor
- weede6weed
- Outcome
- weed invasionse6
- Direction
- decreaseinferrede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e6“Although the study demonstrated that increasing seeding rate can suppress weed invasions, N fertilizer facilitated them”
Claim · model-written summary
N fertilizer facilitated weed invasions.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- N fertilizere6
- Interactor
- weede6weed
- Outcome
- weed invasionse6
- Direction
- increaseinferrede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Yield of Alfalfa and Weeds”
e6“Although the study demonstrated that increasing seeding rate can suppress weed invasions, N fertilizer facilitated them”
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See all 6 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.