Remote Sensing of Canopy Cover in Horticultural Crops

Abstract

<jats:p>Canopy cover (CC) is an important indicator of stage of growth and crop water use in horticultural crops. Remote sensing of CC has been studied in several major crops, but not in most horticultural crops. We measured CC of 11 different annual and perennial horticultural crops in various growth stages on 30 fields on the west side of California's San Joaquin Valley with a handheld multispectral digital camera. Canopy cover was compared with normalized difference vegetation index (NDVI) values calculated from Landsat 5 satellite imagery. The NDVI was highly correlated and linearly related with measured CC across the wide range of crops, canopy structures, and growth stages (R<jats:sup>2</jats:sup> = 0.95, <jats:italic>P</jats:italic> &lt; 0.01) and predicted CC with mean absolute error of 0.047 up to effective full cover. These results indicate that remotely sensed NDVI may be an efficient way to monitor growth stage, and potentially irrigation water demand, of horticultural crops.</jats:p>

Validating FAO AquaCrop using Landsat images and regional crop information

“…Unlike many earlier studies relating VI and CC for crops (e.g. Carlson and Ripley, 1997;Gutman and Ignatov, 1998;Calera et al, 2001;Trout et al, 2008), Johnson and Trout (2012) proposed a general relationship using 18 different crops (including maize, barley, and alfalfa) with high goodness of fit. Accordingly CC is estimated as:…”

“…CC, for instance, is frequently correlated with vegetation indices (VI) from multispectral images (e.g. Johnson and Trout, 2012;Trout et al, 2008;Lopez-Urrea et al, 2009;Calera et al, 2001). For AGB estimation, radiance use efficiency (RUE) model (Monteith, 1972) is often incorporated into RS models (e.g.…”

Remote sensing techniques for predicting evapotranspiration from mixed vegetated surfaces

“…A multi-spectral camera was employed to measure canopy cover while the basal crop coefficient was derived from lysimeter measurements and meteorological parameters. In another study, Trout et al (2008) used a multi-spectral camera to measure canopy cover directly from horticultural crops. They then compared the canopy cover derived from this method with that measured using remotely sensed NDVI.…”

Vegetation index‐based crop coefficients to estimate evapotranspiration by remote sensing in agricultural and natural ecosystems

“…The ground ET data set were limited in that study. However, similar findings were reported by Trout et al () for tree and vegetable crops, and a close correlation was noted between Landsat‐derived f c based on NDVI, and f c measured on the ground over 30 fields with crops ranging from trees (almonds, pistachios), to vines (grapes), and row crops (onions, tomatoes, cantaloupes, watermelon, beans, pepper, garlic and lettuce (Figure ). The only aberrant crop was red lettuce, which has a low NDVI due to reflection of red light from anthocyanin in the leaf cell vacuoles.…”