of the Workshop on âImpact of Climate Change on Agriculture"] Mosonmagyaróvár 2015. szeptember 24. ISBN 978-963-359-057-7. Mulla, D.J. (2013): Twenty ...
Abstract Book - 17th Alps-Adria Scientific Workshop
Using multiple plant sensors to characterise the development of maize (Zea Mays L.) in field experiment Péter RAGÁN 1 - Dénes SULYOK 2 - János NAGY 1 - Endre HARSÁNYI 1 Tamás RÁTONYI 1 1:
Institute
of Land Utilisation Technology
and R e g i o n a l
Development,
Faculty
of Agricultural
and F o o d
S c i e n c e s and E n v i r o n m e n t a l M a n a g e m e n t , U n i v e r s i t y o f D e b r e c e n , H - 4 0 3 2 D e b r e c e n , B ö s z ö r m é n y i street. 138, E - m a i l : r a g a n @ a g r . u n i d e b . h u 2: K I T E Plc. & H - 4 1 8 1 N á d u d v a r , B e m J ó z s e f s q u a r e 1; E - m a i l : s u l y o k d e n e s @ k i t e . h u
K e y w o r d s : m a i z e , S P A D v a l u e , N D V I i n d e x , l e a f area i n d e x , f i e l d e x p e r i m e n t
Introduction In agriculture, decision-making requires a large amount of data (Milics, 2015). Remote sensing applications in precision agriculture began with sensors for soil organic matter and quickly diversified to include satellite aerial and hand held or tractor mounted sensors (Mulla, 2013). The GreenSeeker measurement developed by Stone et al., (2003) collecting the crop canopy reflectance at the red and near-infrared wave band with which normalised difference vegetation index was calculated to estimate the crop growth conditions, plant biomass and patterns of productivity. Leaf chlorophyll content measured with SPAD502 portable chlorophyll meter measures "greenness" of the plants and assesses nitrogen requirement. This "greenness" and the connection amongst acetone extract chlorophyll contents measured in spectrophotometer were examined by Marquard and Tipton (1987), they established that there was a significant correlation amongst the measured values. The assimilating leaf area greatly influences dry matter accumulation in hybrids (Pető, 1993). Materials and methods In the course of the trial, sample areas have been assigned on 4 field plots of Balogh-Farm Tépe Ltd. on the basis of the productivity maps provided by KITE cPlc. Measurement points have been classified into three groups. A weak, a medium and a good productivity zone has been selected for examination on the A,C; and D plots, while on plot B a weak and a good productivity yield zone has been selected. At these measurement points SPAD, NDVI measurements were performed at 4 leaf, 10 leaf and silking stages of maize. Leaf area measurements were performed at 10 leaf stage and silking. Statistical analysis was performed by means of Rstudio. To analyse the connection of NDVI, SPAD, LAI, and NDVI variation coefficient values, a multilinear regression model was elaborated. The purpose of our investigations is the on-site validation of vegetation index measurements more and more frequently utilised in technical advisory systems and the determination of correlations amongst SPAD and LAI values and the NDVI values measured by GreenSeeker. Results and discussion The SPAD, LAI and NDVI variation coefficient values measured at two different dates had a significant influence on the NDVI values measured by the GreenSeeker sensor. Their combined effect is medium week (r=0.45), jointly they affected the measured NDVI values at 20.26% (Table 1)
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Hnanice, Czech Republic - 09-14. April, 2018 Table
1:
Effect
of measured SPAD,
LAI and variation
coefficient data
on
the NDVI values
measured by
GreenSeekersensor Measured value
Significance
Correlation
SPAD
0.03504*
r
0.4501
LAI
0.01546*
r2
0.2026
CV NDVI
12
4 413*10' ***
2
r %
20.26
S i g n i f i c a n c e codes: 0 ' * * * ' 0.001 ' * * ' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Conclusions SPAD and LAI values had a weak correlation with NDVI values. The reason for the weak correlation is that in the early stage of maize development, the NDVI measuring sensor detects a large area of soil beside the plant, which greatly influences the measured values. In addition, upon silking the scattered pollen covers the plant, affecting the correlation between the measured NDVI values and SPAD and LAI values. We have found that the time and circumstances of the measurement greatly influence the usability o f N D V I values. Acknowledgement The research is supported by the project "Establishing a scale-independent complex precision consultancy system (GINOP-2.2.1-15-2016-00001)" The publication is supported by the EFOP-3.6.3-VEKOP-16-2017-00008 project. The project is co-financed by the European Union and the European Social Fund. The field trial and the analyses is supported by KITE cPlc. References M a r q u a r d , R. D., Tipton J. L.: (1987): R e a l t i o n s h i p b e t w e e n chlorophyll and an in situ m e t h o d to estimate leaf greennes. H o r t S c i e n c e . 22: 1327 Milics G.: (2015): D a t a collection m e t h o d s f o r agricultural m o d e l s [In: N e m é n y i M., N y é k i A. (szerk) P r o c e e d i n g s of the W o r k s h o p on „ I m p a c t of C l i m a t e C h a n g e on A g r i c u l t u r e " ] M o s o n m a g y a r ó v á r 2015. s z e p t e m b e r 24. ISBN
978-963-359-057-7
Mulla, D.J. (2013): Twenty five y e a r s of r e m o t e sensing in p r e c i s i o n agriculture: K e y a d v a n c e s and r e m a i n i n g k n o w l e d g e gaps. B i o s y s t e m s engineering. Vol 114, Issue 4. 3 5 8 - 3 7 1 . Pető M. (2013): A n ö v é n y é l e t t a n alapjai. A k a d é m i a Kiadó, B u d a p e s t .
178. I S B N : 9 6 3 0 5 7 5 4 3 4
Stone, M . L . , N e e d h a m , D., Solie, J.B., (2003): Optical spectral r e f l e c t a n c e sensor and controller. US. Pattent 6,596,996.
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