Aerial multispectral imaging for crop hail damage assessment in potato

Abstract

Crop loss assessment after an event of hailstorm can be inaccurate, subjective, inconsistent, and time consuming with the conventional method. Low-altitude, high-resolution aerial imaging using an unmanned aerial vehicle can be utilized for rapid assessment of target crops in a large scale, which can potentially improve the evaluation procedure. The goal of this study was to evaluate the feasibility of rapid and accurate assessment of crop damage due to simulated hailstorms using aerial multispectral imaging. Field experiments were conducted during two seasons in two potato varieties (Russet Norkotah, Ranger Russet) with three levels of mechanical defoliation (33%, 66%, and 99%) at three growth stages (tuber initiation, early bulk, and late bulk). All defoliation treatments were compared to the non-treated control plots (0% defoliation). Aerial multispectral images were collected between 77 and 108 days after planting (0 to 60 days after damage). Vegetation indices such as green normalized difference vegetation index (GNDVI), normalized difference vegetation index, and soil-adjusted vegetation index were calculated from replicate plots of different treatments. Results from two seasons showed similar trends in GNDVI values, with maximum effect of hail damage observed in tuber initiation stages. The mean GNDVI value was significantly lower in crops with the severe damage (99%

Unmanned Aerial Vehicles (UAVs) in environmental biology: a review

“…Not only extreme wind but also the effects of other exceptional meteorological phenomena, such as hail, can be monitored using UAV. Zhou et al (2016) simulated hail events of different severity on two varieties of potato at three different growth stages. A multispectral camera with red, green, blue and NIR bands installed underneath the octocopter was set to collect imagery at different time points (0-60 days) after the damage occurred.…”

Using Unmanned Aerial Vehicles in Postfire Vegetation Survey Campaigns through Large and Heterogeneous Areas: Opportunities and Challenges

“…The use of lightweight unmanned aerial vehicles (UAVs) usually implies lower economic costs than other remote sensing techniques when surveying relatively small areas [ 11 , 13 , 14 , 15 , 16 ] and their low flight speed and flight altitude enables ultra-high spatial resolution (better than 20 cm) imagery [ 11 ] to be taken. In burned areas, vegetation recovery is not homogeneous due to the spatial variation in fire regime, pre-fire plant community composition and environmental characteristics [ 17 ].…”

“…Most common cameras employed in UAV surveys are digital RGB cameras [ 11 , 40 ] or digital cameras where one of the visible bands has been adapted for NIR imagery acquisition [ 16 , 32 ]. Also, multispectral cameras, such as Tetracam ADC Lite [ 41 ] or MicaSense RedEdge [ 42 ], have been chosen to perform aerial surveys.…”

Calibrating Sentinel-2 Imagery with Multispectral UAV Derived Information to Quantify Damages in Mediterranean Rice Crops Caused by Western Swamphen (Porphyrio porphyrio)

“…Lightweight UAVs and photogrammetric derived information as Digital Surface Models (DSM) have been used to calculate crop damages by means of crop height estimation [25] or grapevine canopy changes [26]. UAV multispectral information is also becoming very important due to its ability to asses vegetation stress and damages through vegetation indices [27,28]. In fact, this ability can be very useful to detect Western Swamphen damages, usually resulting in small and medium vegetation gaps and plant vigor decreases in rice crops.…”