Hyperspectral Reflectance and Indices for Characterizing the Dynamics of Crop–Weed Competition for Water

Inbal Ronay,Dan G. Blumberg,Jhonathan E. Ephrath,Shimrit Maman,Hanan Eizenberg

doi:10.3390/rs13030513

Inbal Ronay, Dan G. Blumberg + Show 3 more

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https://doi.org/10.3390/rs13030513

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Abstract

Understanding the spectral characteristics of crops in response to stress caused by weeds is a basic step in improving the precision of agricultural technologies that manage weeds in the field. This research focused on the competition between corn (Zea mays) and redroot pigweed (Amaranthus retroflexus), a common weed that strongly reduces corn yield. The aim of this research was to characterize the physiological changes that occur in corn during early growth because of crop–weed competition and to examine the ability to detect the effect of competition through hyperspectral measurements. A greenhouse experiment was conducted, and corn plants were examined during early growth, with and without weed competition. Hyperspectral measurements were combined with physiological measurements to examine the reflectance and photosynthetic activity of corn. Changes were expected to appear mainly in the short-wave infrared region (SWIR) due to competition for water. Relative water content (RWC), chlorophyll content, photosynthetic rate, and stomatal conductance were reduced in the presence of weeds, and intercellular CO2 levels increased. Deeper SWIR light absorption occurred in the weed treatment as expected, accompanied by spectral changes in the visible (VIS) and near infrared (NIR) ranges. The results highlight the potential of using spectral measurements as an indicator of competition for water.

Highlights

The use of remote sensing technologies in agriculture is of great interest, enabling rapid and non-destructive measurements that can be used for research and field applications.Many studies have demonstrated the potential of spectral tools for the detection of plant responses to various biotic and abiotic stressors [1,2,3,4,5]
The primary objective of the current study was to examine the potential of hyperspectral measurements to detect changes that result from crop–weed competition
Its effect was detected in several bands of the short-wave infrared region (SWIR) absorption minima (~1450, ~1800, ~2400 nm), presenting deeper light absorption for weed-free corn compared to that in corn grown with weeds

Summary

Introduction

The use of remote sensing technologies in agriculture is of great interest, enabling rapid and non-destructive measurements that can be used for research and field applications. Many studies have demonstrated the potential of spectral tools for the detection of plant responses to various biotic and abiotic stressors [1,2,3,4,5]. The specific spectral responses related to plant competition and weed stress are not widely addressed. Hyperspectral sensors are robust for these applications; characterization of the spectral reflectance features of important crops and weed species over a wide range of environmental conditions is still needed to apply these methods commercially [9]. While most studies focus on the detection of weeds in the field, only a few studies have demonstrated the use of remote sensing methods for the

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