Paper · 2023 · European Journal of Agronomy

Understanding the spatio-temporal behavior of crop yield, yield components and weed pressure using time series Sentinel-2-data in an organic farming system

Stefano Marino

7
claims
14
verbatim quotes
26
citations
3
research areas
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Open access · cc-by

Abstract

Organic farming has begun to represent a practical alternative for reducing the environmental impact of crop production and increasing biodiversity. In agricultural systems, the growing demand for stable crop production requires the adoption of useful tools for the sustainable intensification of agriculture. While organic farming systems face various drawbacks, which affect crop yield. Among the limiting factors, weed management is one of the most difficult aspects of organic farming. The aim of the study was (i) to evaluate the effect of weed pressure on yield spatial variability (ii) to analyze the spatial variability of yield and yield components based on hand-sampled yield data (iii) to evaluate the ability of the most commonly used vegetation index (NDVI) derived from Sentinel-2 satellite platforms to understand within-field spatial and temporal variability during the crop cycle (iv) to evaluate the ability of the cluster analysis procedures on NDVI satellite data to identify, discriminate and map sub-areas with different yield, yield components, and weed pressure at the farm level in an organic farming system. Remote sensing techniques (Sentinel-2 images), vegetation index (NDVI), cluster analysis (Hierarchical clustering Ward’s minimum variance approach) and hand-sampled data (georeferenced yield and yield components field data) were used for understanding the spatio-temporal behavior of crops. The cluster analysis of NDVI data from Sentinel-2 collected at eight different stages detected the crop spatial and temporal variability at an early stage. In an open field of 24 ha, an area of about 9 ha, showed a high weed level with a yield average value 78 % lower than the most productive cluster area. The yield components, especially the spike number per square meter, also recorded very low values, mainly due to the negative effect of the high presence of weeds (in particular oats), which reached average values of 250 g m-2. An area of 7.3 ha showed the highest yield at harvest with a yield value 45 % higher than the mean harvest data. The study highlights that from the early tillering stage to the booting stage the NDVI maps derived from the Satellite Sentinel-2 and clustered by Ward’s method represent the weeds distribution impact on crop yield and yield components and an early warning for the assessment of one of the most important limiting factors in organic farming. Sentinel-2 data and cluster analysis can improve an efficient assessment and management strategies in an organic farming agricultural system. Furthermore, the use of precision agriculture tools in organic farming can lead to a site‐specific management at the farm level and therefore a sustainable intensification of agriculture systems.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗

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Claims 7

Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

Clustering Sentinel-2 NDVI detected early spatial and temporal crop variation.

Taxon
cropt0
Outcome
crop spatial and temporal variabilitye0
Value
eight different stagese0

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“The cluster analysis of NDVI data from Sentinel-2 collected at eight different stages detected the crop spatial and temporal variability at an early stage”

✓ located verbatim in the source · abstract, characters 1425–1579 · show in text ↑
Associationobservedoriginal resultnegativemeasured

Claim · model-written summary

A high-weed area of about 9 ha had mean yield 78% below the most productive cluster.

Taxon
cropt0
Interactor
weede0weed
Outcome
yield average valuee0
Direction
lowere0
Value
78 %e0
Comparator
the most productive cluster areae0
Setting
an area of about 9 hae0

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“an area of about 9 ha, showed a high weed level with a yield average value 78 % lower than the most productive cluster area”

✓ located verbatim in the source · abstract, characters 1608–1731 · show in text ↑
Associationobservedoriginal resultnegativemeasured

Claim · model-written summary

Spike number per square metre was low where weeds were abundant.

Taxon
cropt0
Interactor
oatsAvena sativae0weed
Outcome
spike number per square metere0
Direction
very lowe0
Qualifier
250 g m-2e0

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

Avena sativa
Avena sativa · InteractorSendelbach ( talk ) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“The yield components, especially the spike number per square meter, also recorded very low values, mainly due to the negative effect of the high presence of weeds (in particular oats), which reached average values of 250 g m-2”

✓ located verbatim in the source · abstract, characters 1733–1959 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

A 7.3 ha area had harvest yield 45% above the field mean.

Taxon
cropt0
Outcome
yield at harveste0
Direction
highere0
Value
45 %e0
Comparator
the mean harvest datae0
Setting
An area of 7.3 hae0

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“An area of 7.3 ha showed the highest yield at harvest with a yield value 45 % higher than the mean harvest data”

✓ located verbatim in the source · abstract, characters 1961–2072 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

Clustered Sentinel-2 NDVI maps from tillering to booting represented the effect of weed distribution on crop yield and components.

Taxon
cropt0
Organ / stage
early tillering stage to the booting stagee0
Interactor
weedse0weed
Outcome
weeds distribution impact on crop yield and yield componentse0

Not reportedComparatorValue

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“from the early tillering stage to the booting stage the NDVI maps derived from the Satellite Sentinel-2 and clustered by Ward’s method represent the weeds distribution impact on crop yield and yield components”

✓ located verbatim in the source · abstract, characters 2100–2309 · show in text ↑
Recommendationauthor interpretationoriginal resultbasis n/a

Claim · model-written summary

The authors propose Sentinel-2 clustering as an early warning tool for weed limitation in organic farming.

Taxon
cropt0
Outcome
an early warning for the assessment of one of the most important limiting factors in organic farminge0

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“an early warning for the assessment of one of the most important limiting factors in organic farming”

✓ located verbatim in the source · abstract, characters 2314–2414 · show in text ↑
Recommendationauthor interpretationoriginal resultbasis n/a

Claim · model-written summary

The authors suggest precision agriculture tools can support site-specific organic farm management.

Taxon
cropt0
Outcome
site‐specific management at the farm levele0

Verbatim

t0

“crop”

✓ located verbatim in the source · title, characters 46–50 · show in text ↑
e0

“the use of precision agriculture tools in organic farming can lead to a site‐specific management at the farm level”

✓ located verbatim in the source · abstract, characters 2571–2685 · show in text ↑