Canopy chlorophyll content (CCC) is an essential ecophysiological variable for photosynthetic functioning. Remote sensing of CCC is vital for a wide range of ecological and agricultural applications. The objectives of this study were to explore simple and robust algorithms for spectral assessment of CCC. Hyperspectral datasets for six vegetation types (rice, wheat, corn, soybean, sugar beet and...

The objectives of this work were to determine the effect of sink strength (presence or absence of pods) and nitrogen source (nodulating versus nonnodulating plants) on enzymic activities, chlorophyll concentration, and senescence of soybean (Glycine max [L.] Merr. cv Harosoy) isolines. A 2-year (1981-1982) field study was conducted.For both nodulated and nonnodulated plants, ribulose bisphospha...

Estimation of vegetation water content (VWC) by optical remote sensing improves soil moisture retrievals from passive microwave radiometry. For a variety of vegetation types, the largest unknown for predicting VWC is stem water content, which is assumed to be allometrically related to the water content of the plant canopy. For maize and soybean, measured stem water contents were highly correlat...

Increased concentrations of CO2 and ozone are predicted to lower nutritional quality of leaves for insect herbivores, which may increase herbivory as insects eat more to meet their nutritional demands. To test this prediction, we measured levels of herbivory in soybean grown in ambient air and air enriched with CO2 or O3 using free air gas concentration enrichment (FACE). Under open-air conditi...

The estimation of crop chlorophyll content could provide technical support for precision agriculture. Canopy spectral reflectance was simulated for different chlorophyll levels using radiative transfer models. Then with multiperiod measured hyperspectral data and corresponding chlorophyll content, after extracting six wavelet energy coefficients from the responded bands, an evaluation of soybea...

A primary focus of this short communication is to show how the operational definition of light use efficiency (LUE) influences the results and interpretation of the LUE model. Our study was motivated by the observation that multiple LUE definitions are reported in the literature. The temporal behavior of three operational definitions of LUE, based on (i) incident radiation, (ii) total absorbed ...

Impacts of salinity become severe when the soil is deficient in oxygen. Oxygation (using aerated water for subsurface drip irrigation of crop) could minimize the impact of salinity on plants under oxygen-limiting soil environments. Pot experiments were conducted to evaluate the effects of oxygation (12% air volume/volume of water) on vegetable soybean (moderately salt tolerant) and cotton (salt...

A field study was conducted to increase our understanding of diel activity patterns of Colaspis brunnea (F.) and Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) in key crop habitats. Within 24-h periods, C. brunnea was sampled in clover fields (primarily red clover, Trifolium pretense (L.), with some sweet clover, Melilotus officinalis (L.) Pallas, and downy brome, Bromus tectorum (L...

The genomic and postgenomic eras have provided unprecedented potential to understand plants’, microbes’, and even entire communities’ molecular and cellular responses to global change. Early efforts to apply genomic technologies and concepts to climate change research are already improving our capability to predict organism response to such change. For example, genome-wide analyses of soybean a...

In this study, a model for estimating crop gross primary production (GPP) using the product of a chlorophyll-related vegetation index (VI) and incident photosynthetically active radiation (PARin) was developed and tested. This model, which may be based entirely on satellite data, was tested using Landsat and MODIS data for GPP estimation in both maize and soybean, crop types that differ in leaf...