Paper · 2019 · PLoS ONE

Effects of nutrient level and planting density on population relationship in soybean and wheat intercropping populations

Jialing Huang; Yihang Li; Yu Shi; et al.

8
claims
15
verbatim quotes
15
citations
2
research areas
✓
Open access · cc-by

Abstract

A positive interaction between plant populations is a type of population relationship formed during long-term evolution. This interaction can alleviate population competition, improve resource utilization in populations, and promote population harmony and community stability. However, cultivated plant populations may have insufficient time to establish a positive interaction, thereby hindering the formation of the positive interaction. As current studies have not fully addressed these issues, our study established soybean/wheat intercropping populations beneficial for growth and explored the effects of nutrient level and planting density on the positive interaction between the two crops. Changes across population modules in both sole cropping and intercropping populations of soybean and wheat were analyzed. Results using nutrient levels of ½- or ¼-strength Hoagland solution indicated that soybean/wheat intercropping population modules significantly increased at low planting densities (D20 and D26) and significantly decreased at high planting densities (D32 and D60). Therefore, as planting density increased, the modules of both intercropping populations initially increased before decreasing. Similarly, positive interaction initially strengthened before weakening. Moreover, at an intermediate planting density, the population modules reached their maxima, and the positive interaction was the strongest. Under the same planting density, ¼-strength Hoagland solution recorded better growth for the soybean/wheat intercropping population modules compared to results using the ½-strength Hoagland solution. These findings indicated that low nutrient level can increase the positive interaction of intercropping populations at a given planting density, and that environmental nutrient level and population planting densities constrain the positive interaction between soybean and wheat populations in the intercropping system. This study highlights issues that need to be addressed when constructing intercropping populations.

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Claims 8

Observationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Intercropping modules increased at low density with the stated nutrient levels.

Outcome
intercropping population modulese0
Direction
increasede0

Not reportedSetting

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“soybean/wheat intercropping population modules significantly increased at low planting densities (D20 and D26)”

✓ located verbatim in the source · abstract, characters 902–1012 · show in text ↑
Observationobservedoriginal resultnegativesignificant (as stated)measured

Claim · model-written summary

Intercropping modules decreased at high density.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Outcome
intercropping population modulese1
Direction
decreasede0

Not reportedSetting

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“significantly decreased at high planting densities (D32 and D60)”

✓ located verbatim in the source · abstract, characters 1017–1081 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑
e1

“soybean/wheat intercropping population modules significantly increased at low planting densities (D20 and D26)”

✓ located verbatim in the source · abstract, characters 902–1012 · show in text ↑
Associationobservedoriginal resultmixedmeasured

Claim · model-written summary

Modules first rose and then fell as planting density increased.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Treatment
planting densitye0
Outcome
modules of both intercropping populationse0
Direction
initially increased before decreasinge0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“as planting density increased, the modules of both intercropping populations initially increased before decreasing”

✓ located verbatim in the source · abstract, characters 1094–1208 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑
Observationobservedoriginal resultmixedmeasured

Claim · model-written summary

Positive interaction first strengthened and then weakened.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Outcome
positive interactione0
Direction
initially strengthened before weakeninge0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“positive interaction initially strengthened before weakening”

✓ located verbatim in the source · abstract, characters 1221–1281 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

Modules reached their maxima at intermediate density.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Treatment
intermediate planting densitye0
Outcome
population modulese0
Direction
maximae0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“at an intermediate planting density, the population modules reached their maxima”

✓ located verbatim in the source · abstract, characters 1293–1373 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

Positive interaction was strongest at intermediate density.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Treatment
intermediate planting densitye0
Outcome
positive interactione0
Direction
strongeste0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“at an intermediate planting density, the population modules reached their maxima, and the positive interaction was the strongest”

✓ located verbatim in the source · abstract, characters 1293–1421 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Quarter-strength nutrient solution gave better module growth than half-strength solution.

Treatment
¼-strength Hoagland solutione0
Outcome
growth for the soybean/wheat intercropping population modulese0
Direction
bettere0
Comparator
½-strength Hoagland solutione0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“¼-strength Hoagland solution recorded better growth for the soybean/wheat intercropping population modules compared to results using the ½-strength Hoagland solution”

✓ located verbatim in the source · abstract, characters 1456–1621 · show in text ↑
Intervention effectauthor interpretationoriginal resultpositivemeasured

Claim · model-written summary

Low nutrients increased positive interaction at a given density.

Taxon
soybean and wheatGlycine maxTriticum aestivumt0
Treatment
low nutrient levele0
Outcome
positive interactione0
Direction
increasee0
Qualifier
at a given planting densitye0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“low nutrient level can increase the positive interaction of intercropping populations at a given planting density”

✓ located verbatim in the source · abstract, characters 1653–1766 · show in text ↑
t0

“soybean and wheat intercropping populations”

✓ located verbatim in the source · title, characters 77–120 · show in text ↑