Abstract
This study aimed to investigate the temporal effects of different fertilization strategies on the physiological, morphological, and biomass-related traits of soybean under controlled greenhouse conditions. Individual and combined applications of urea, zinc (Zn), and microbial inoculants were evaluated using a multi-sensor approach. Optical parameters (SPAD, NDVI), plant height, and thermal imaging were monitored across days after onset (DAO), and post-harvest biomass traits were measured to establish integrative relationships. The findings demonstrated that SPAD values increased by 18-27% and NDVI by up to 22%, with combined treatments (Urea + Microbial, Zn + Microbial) showing the most pronounced improvements. Urea + Microbial increased plant height by 15% and fresh biomass by 28% compared to the control. Thermal imaging revealed a 1.8-2.5 °C reduction in canopy temperature under combined treatments, indicating enhanced stomatal regulation and water-use efficiency. Strong positive correlations (r = 0.71-0.84) between SPAD/NDVI and post-harvest biomass confirmed the reliability of early-stage sensor measurements for predicting yield-related traits. Importantly, the integration of microbial inoculants with mineral fertilizers enhanced both physiological resilience and water-use efficiency, while the identification of tentative threshold values for SPAD (~ 35) and NDVI (~ 0.60) provides practical benchmarks for fertilization decisions and automation in precision agriculture. Overall, this study highlights the utility of combining optical and thermal sensing with morphological and biomass assessments to optimize fertilization strategies in soybeans. The results provide novel insights into the role of micronutrient (Zn) and microbial management in crop monitoring and underline the potential of sensor-based approaches to improve nutrient efficiency and support sustainable agricultural production.
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Claims 9
Claim · model-written summary
Combined fertilization increased SPAD by 18-27%.
- Taxon
- soybean
Glycine maxt0 - Treatment
- Urea + Microbiale0
- Outcome
- SPAD valuese0
- Direction
- increasede0
- Value
- 18-27%e0
Not reportedComparatorSetting
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SPAD values increased by 18-27% and NDVI by up to 22%, with combined treatments (Urea + Microbial, Zn + Microbial) showing the most pronounced improvements.”
t0“soybean”
Claim · model-written summary
Combined fertilization increased NDVI by up to 22%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SPAD values increased by 18-27% and NDVI by up to 22%, with combined treatments (Urea + Microbial, Zn + Microbial) showing the most pronounced improvements.”
t0“soybean”
Claim · model-written summary
Urea plus microbial inoculant raised height by 15% versus control.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Urea + Microbiale0
- Interactor
- Microbiale0symbiont
- Outcome
- plant heighte0
- Direction
- increasede0
- Value
- 15%e0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea + Microbial increased plant height by 15% and fresh biomass by 28% compared to the control.”
t0“soybean”
Claim · model-written summary
Urea plus microbial inoculant raised fresh biomass by 28% versus control.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Urea + Microbiale0
- Outcome
- fresh biomasse0
- Direction
- increasede0
- Value
- 28%e0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea + Microbial increased plant height by 15% and fresh biomass by 28% compared to the control.”
t0“soybean”
Claim · model-written summary
Combined treatments lowered canopy temperature by 1.8-2.5 °C.
- Taxon
- soybeanGlycine maxt0
- Treatment
- combined treatmentse0
- Outcome
- canopy temperaturee0
- Direction
- reductione0
- Value
- 1.8-2.5 °Ce0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 1.8-2.5 °C reduction in canopy temperature under combined treatments”
t0“soybean”
Claim · model-written summary
SPAD and NDVI positively correlated with postharvest biomass.
- Taxon
- soybeanGlycine maxt0
- Outcome
- post-harvest biomasse0
- Direction
- positivee0
- Value
- r = 0.71-0.84e0
- Comparator
- SPAD/NDVIe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strong positive correlations (r = 0.71-0.84) between SPAD/NDVI and post-harvest biomass”
t0“soybean”
Claim · model-written summary
Early sensor readings were reliable for predicting yield-related traits.
- Taxon
- soybeanGlycine maxt0
- Outcome
- reliability of early-stage sensor measurements for predicting yield-related traitse0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“confirmed the reliability of early-stage sensor measurements for predicting yield-related traits.”
t0“soybean”
Claim · model-written summary
SPAD around 35 was proposed as a fertilization decision threshold.
- Taxon
- soybeanGlycine maxt0
- Outcome
- threshold values for SPADe0
- Value
- ~ 35e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tentative threshold values for SPAD (~ 35) and NDVI (~ 0.60) provides practical benchmarks for fertilization decisions”
t0“soybean”
Claim · model-written summary
NDVI around 0.60 was proposed as a fertilization decision threshold.
- Taxon
- soybeanGlycine maxt0
- Outcome
- NDVIe0
- Value
- ~ 0.60e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tentative threshold values for SPAD (~ 35) and NDVI (~ 0.60) provides practical benchmarks for fertilization decisions”
t0“soybean”
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