1 research outputs found
Not Available
Not AvailableThe best and commonly used ground - based sensor
to monitor crop growth, ASD FieldSpecPro Spectroradiometer
(Analytical Spectral Devices, Boulder, CO, USA) is
a passive sensor, which can be used under adequate light
condition. However, now - a - days active sensors such as
GreenSeekerTM (GS) handheld crop response (Trimble
Agriculture division, USA) are used for monitoring crop
growth and are flexible in terms of timeliness and illumination
conditions besides being cheaper than the ASD. Before its
wide use, the suitability and accuracy of GS should be
assessed by comparing the NDVI measured by this instrument
with that by ASD, under diverse wheat growing conditions of
India. Keeping this in view, the present experiment was
undertaken with the following objectives: (1) to find out the
temporal variation of NDVI measured both by ASD and GS
treatments, (2) to find out relationship between the NDVI
measured through ASD and GS and, (3) to evaluate the suitability
of GS for NDVI measurements. It was observedthatthe
numerical value of NDVI as measured by GS was always
significantly (P \ 0.05) lower than that measured by ASD for
all the experiments under study. The NDVI - ASD and NDVIGS
were significantly positively correlated (P \ 0.01) with
the correlation coefficients being ?0.94, ?0.88 and ?0.87 for
irrigation and nitrogen experiment, irrigation and cultivars
experiment, and tillage, residue and nitrogen experiments,
respectively. Further, the regression equation developed
between the NDVI - ASD and NDVI - GS: [NDVIGS
= 1.070 9 (NDVI - ASD - 0.292] can be successfully
used to compute the NDVI of ASD from that computed by GS.Not Availabl