Abstract
Methods for estimating the N response of sugarcane ( Saccharum spp.) while considering a variable rate of N application are required to allow for improved nitrogen use efficiency (NUE) and higher yields. The objectives of this work were to compare the performance of three vegetation indices obtained from canopy sensor data to assess N in sugarcane fields at various crop stalk height as well as to determine the ability of these in‐season sensor readings to predict the response of yield to N. Seven experiments were conducted in Brazil under different site conditions from 2009 to 2011. The treatments comprised five N application rates ranging from 0 to 200 kg N ha –1 . A CropCircle canopy sensor (model ACS‐210, Holland Scientific Inc., Lincoln, NE) was used to determine the amber normalized difference vegetation index ( a NDVI), chlorophyll index (CI), and inverse of the simple ratio (ISR) at different crop stalk heights. The N application increased the yield in only three fields ( p < 0.1). The best results using the canopy sensor readings, chlorophyll and leaf N content were found when the average crop stalk height was between 0.4 and 0.7 m. A weak relationship was observed between the vegetation indices and N from tissue analyses. The best results were obtained with the ISR due to its high r 2 , low root mean square error (RMSE), and consequently higher SEq with respect to sugarcane yield. The canopy reflectance sensor is a useful tool for identifying the variability within fields and to determine the variable rate of in‐season N fertilizer application in sugarcane fields.
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Claims 5
Claim · model-written summary
Nitrogen increased sugarcane yield in only three fields.
- Taxon
- Sugarcanet0
- Treatment
- N applicatione0
- Outcome
- yielde0
- Direction
- increasede0
- Qualifier
- only three fieldse0
Not reportedComparator
Verbatim
e0“The N application increased the yield in only three fields ( p < 0.1).”
t0“Sugarcane”
Claim · model-written summary
Sensor readings, chlorophyll and leaf nitrogen content performed best at stalk heights of 0.4 to 0.7 m.
Verbatim
e0“The best results using the canopy sensor readings, chlorophyll and leaf N content were found when the average crop stalk height was between 0.4 and 0.7 m.”
t0“Sugarcane”
Claim · model-written summary
Vegetation indices were weakly related to tissue nitrogen.
Not reportedDirection
Verbatim
e0“A weak relationship was observed between the vegetation indices and N from tissue analyses.”
t0“Sugarcane”
Claim · model-written summary
ISR gave the best canopy sensor prediction results for sugarcane yield.
Verbatim
e0“The best results were obtained with the ISR due to its high r 2 , low root mean square error (RMSE), and consequently higher SEq with respect to sugarcane yield.”
t0“Sugarcane”
Claim · model-written summary
The canopy reflectance sensor was considered useful for within-field variability and variable-rate nitrogen application.
Verbatim
e0“The canopy reflectance sensor is a useful tool for identifying the variability within fields and to determine the variable rate of in‐season N fertilizer application in sugarcane fields.”
The same questions in other papers
nitrogen · yield · Saccharum officinarum (sugarcane)Results differ
117 papers in the same direction as this paper · 15 in the opposite direction · 4 reporting no difference from an alternative
- negative
- no effect
- negative
133 papers more in this group
See all 137 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.