Abstract
Minimizing inputs such as fertilizers, herbicides, or tillage may be sought by producers to satisfy economic as well as environmental goals. One of the challenges in reducing inputs, whether synthetic fertilizers or herbicides, or substituting a synthetic nutrient with an organic source, is to identify practices that will provide optimum growing conditions for the crop while maintaining an adequate level of weed control. Our objective was to measure the cumulative effects of 12 yr of nitrogen (N) and phosphorus (P) fertilization treatments applied to two tillage systems [conventional tillage (CT) vs. no tillage (NT)] in a corn–soybean rotation on weed communities and crop yields. Residual (postherbicide treatment) weed species assembly was determined by multivariate analysis and was influenced mainly by tillage, with weeds more strongly associated with NT than with CT. Diversity of weed communities as measured by richness, evenness (E ), and a diversity index (H9), and total weed biomass were greater for NT than for CT. Nutrient treatments had little or no effect on these parameters. Corn yields were reduced by 70% in the absence of N and by 25% in NT compared to CT treatments. Soybean yields were reduced in NT with increasing P rates compared to other treatments, but reductions never exceeded 10%. Overall, corn and soybean had different responses to treatments, with corn yields being far more affected by fertilization and tillage than soybean yields. Conversely, the absence of tillage had a much greater effect than the absence of nutrient input on weed community assembly and biomass, suggesting the importance of a weed management program specifically tailored for NT systems. Nomenclature: Corn, Zea mays L.; soybean, Glycine max (L.) Merr.
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Claims 8
Claim · model-written summary
Weed assembly was influenced mainly by tillage.
Not reportedDirection
Verbatim
e0“Residual (postherbicide treatment) weed species assembly was determined by multivariate analysis and was influenced mainly by tillage”
t0“Crops”
Claim · model-written summary
Weeds were more strongly associated with no tillage than conventional tillage.
Verbatim
e0“weeds more strongly associated with NT than with CT”
t0“Crops”
Claim · model-written summary
Weed diversity and biomass were greater under no tillage.
Verbatim
e0“Diversity of weed communities as measured by richness, evenness (E ), and a diversity index (H9), and total weed biomass were greater for NT than for CT”
t0“Crops”
Claim · model-written summary
Nutrient treatments had little or no effect on weed diversity and biomass.
Not reportedComparator
Verbatim
e0“Nutrient treatments had little or no effect on these parameters”
t0“Crops”
Claim · model-written summary
Corn yield fell 70% without nitrogen.
- Taxon
- Corn
Zea mays subsp. mayse0 - Treatment
- absence of Ne0
- Outcome
- Corn yieldse0
- Direction
- reducede0
- Value
- 70%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn yields were reduced by 70% in the absence of N”
Claim · model-written summary
Corn yield fell 25% under no tillage versus conventional tillage.
- Taxon
- CornZea mays subsp. mayse0
- Treatment
- NTe0
- Outcome
- Corn yieldse0
- Direction
- reducede0
- Value
- 25%e0
- Comparator
- CT treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn yields were reduced by 70% in the absence of N and by 25% in NT compared to CT treatments”
Claim · model-written summary
Soybean yield declined under no tillage as phosphorus rates rose, by no more than 10%.
- Taxon
- Soybean
Glycine maxe0 - Treatment
- increasing P ratese0
- Outcome
- Soybean yieldse0
- Direction
- reducede0
- Value
- 10%e0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean yields were reduced in NT with increasing P rates compared to other treatments, but reductions never exceeded 10%”
Claim · model-written summary
Authors recommend weed management tailored to no-tillage systems.
Verbatim
e0“suggesting the importance of a weed management program specifically tailored for NT systems”
t0“Crops”
The same questions in other papers
tillage · yield · Zea mays (maize)Positive and negative results
286 papers in the same direction as this paper · 812 in the opposite direction
- negative
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See all 1,099 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.