Spectral Analysis for Monitoring Crop Growth Using Tractor Mounted Spectroradiometer and Hand Held Greenseeker In Cotton

Abstract

Remotely sensed spectral vegetation indices are widely used and have benefited numerous disciplines interested in the assessment of biomass, water use, plant stress, plant health and crop production. Tractor mounted Spectroradiometer and hand held GreenSeeker were used to capture the spectral signatures of cotton crop canopy and to calculate NDVI which indicated the temporal changes in crop canopy, nutritional status and phenological conditions in cotton. The structural mechanism for mounting spectroradiometer on the tractor was prepared with various options of adjustments to use spectroradiometer infield. Spectral signatures of crop were measured using tractor mounted spectroradiometer and GreenSeeker at different growth stages in two cultivars of cotton. The relations between NDVI spectroradiometer (R650 and R770) and plant N, plant biomass and plant height at p=0.05 level of significance were found as quadratic, exponential and linear with maximum value of coefficient of determination (R2) of 0.806, 0.807 and 0.801 respectively. However, the relations between NDVI (Green- Seeker) and plant N, plant biomass and plant height at p=0.05 level of significance were found as quadratic, quadratic and linear with maximum R2 value of 0.828, 0.817 and 0.839 respectively. A close relationship between NDVI Spectro-radiometer (R650 and R770) and NDVI (GreenSeeker) was observed with R2 value of 0.833 at p=0.05 level of significance. The study suggested that NDVI at (R650 and R770) using spectroradiometer can be used as a reliable tool for fertilizer N management in cotton.

Daljinska spektralna detekcija vegetacije se široko koristi u mnogim oblastima u kojima je potrebna procena biomase, korišćenja vode, stresa kod biljaka, zdravlja biljaka i biljne proizvodnje. Traktorski spektroradiometar i ručni sensor stanja useva su korišćeni za snimanje spektralnih potpisa useva pamuka i proračun NDVI indeksa, što je pokazalo povremene promene biljnog pokrivača, nutritivno stanje i fenološke uslove u kojima se pamuk nalazi. Konstrukcija za postavljanje pektroradiometra na traktor je izvedena sa različitim mogućnostima za podešavanje upotrebe uređaja na parceli. Spektralni potpisi useva mereni su spektroradiometrom postavljenim na traktoru i ručnim senzorom stanja useva u različitim fazama porasta kod dve sorte pamuka. Odnsoi između NDVI indeksa spektroradiometra (R650 i R770) i biljnog azota, biomase biljaka i visine biljaka na nivou značajnosti p=0.05 bili su kvadratni, eksponencijalni i linearni, sa maksimalnim vrednostima koeficijenta determinacije (R2) od 0.806, 0.807 i 0.801, redom. Pored ovoga, odnosi između NDVI (Green-Seeker) i biljnog azota, biomase biljaka i visine biljaka na nivou značajnosti p=0.05 bili su kvadratni, kvadratni i linearni, sa maksimalnom vredošću R2 od 0.828, 0.817 i 0.839, redom. Značajna zavisnost NDVI spektroradiometra (R650 i R770) i NDVI (GreenSeeker) bila je utvrđena sa vrednošću R2 od 0.833 na nivou značajnosti p=0.05. Istraživanje je pokazalo da NDVI kod (R650 i R770) upotrebom spektroradiometra može da se upotrebi kao pouzdano sredstvo za upravljanje đubrenjem azotom kod pamuka.