Author
S.B. Idso
Bio: S.B. Idso is an academic researcher from University of California, Davis. The author has contributed to research in topics: Degree day & Equivalence point. The author has an hindex of 3, co-authored 4 publications receiving 1040 citations.
Papers
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TL;DR: In this paper, several experiments involving the measurement of foliage-air temperature differentials (TF-TA) and air vapor pressure deficits (VPD) were conducted on squash, alfalfa, and soybean crops at Tempe and Mesa, Arizona; Manhattan, Kansas; Lincoln, Nebraska; St Paul, Minnesota; and Fargo, North Dakota.
1,094 citations
TL;DR: In this article, data from seven different crops, some of which were grown in three different locations and three different years, with a variety of planting dates, seeding rates, and irrigation regimes have been combined to develop a single broad relationship between yield, as normalized for solar radiation reception over the crop's vegetative growth stage, and the summation of stress-degree-days accumulated over the reproductive growth stage.
48 citations
TL;DR: In this article, the equivalence point of plant and air temperatures is not a universal constant in the vicinity of 33°C, as has long been tacitly assumed to be the case for well-watered vegetation.
32 citations
01 Jan 1980
TL;DR: In this article, a thermal-IR scanner was used to examine the variability in temperature that may exist from one field to another and to determine realistic within-field temperature variations, and it was found that the airborne and the ground-based data agreed very well and that there was less variability in the fields that were completely covered with crops than those of bare soil.
Abstract: Crop stress measured using thermal infrared emission is evaluated with the stress-degree-day (SDD) concept. Throughout the season, the accumulation of SDD during the reproductive stage of growth is inversely related to yield. This relationship is shown for durum wheat, hard red winter wheat, barley, grain sorghum and soybeans. It is noted that SDD can be used to schedule irrigations for maximizing yields and for applying remotely sensed data to management of water resources. An airborne flight with a thermal-IR scanner was used to examine the variability in temperature that may exist from one field to another and to determine realistic within-field temperature variations. It was found that the airborne and the ground-based data agreed very well and that there was less variability in the fields that were completely covered with crops than those of bare soil.
3 citations
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TL;DR: In this article, a system of models for the simulation of gas and energy exchange of a leaf of a C3 plant in free air is presented, where the physiological processes are simulated by sub-models that: (a) give net photosynthesis (An) as a function of environmental and leaf parameters and stomatal conductance (gs); (b) give g, as well as the concentration of CO2 and H2O in air at the leaf surface and the current rate of photosynthesis of the leaf.
2,030 citations
TL;DR: In this paper, a crop water stress index (CWSI) was calculated using infrared thermometry, along with wet and dry-bulb air temperatures and an estimate of net radiation.
Abstract: Canopy temperatures, obtained by infrared thermometry, along with wet- and dry-bulb air temperatures and an estimate of net radiation were used in equations derived from energy balance considerations to calculate a crop water stress index (CWSI). Theoretical limits were developed for the canopy air temperature difference as related to the air vapor pressure deficit. The CWSI was shown to be equal to 1 - E/Ep, the ratio of actual to potential evapotranspiration obtained from the Penman-Monteith equation. Four experimental plots, planted to wheat, received postemergence irrigations at different times to create different degrees of water stress. Pertinent variables were measured between 1340 and 1400 each day (except some weekends). The CWSI, plotted as a function of time, closely paralleled a plot of the extractable soil water in the 0- to 1.1-m zone. The usefulness and limitations of the index are discussed.
1,642 citations
TL;DR: The spectral characteristics of vegetation are introduced and the development of VIs are summarized, discussing their specific applicability and representativeness according to the vegetation of interest, environment, and implementation precision.
Abstract: Vegetation Indices (VIs) obtained from remote sensing based canopies are quite simple and effective algorithms for quantitative and qualitative evaluations of vegetation cover, vigor, and growth dynamics, among other applications These indices have been widely implemented within RS applications using different airborne and satellite platforms with recent advances using Unmanned Aerial Vehicles (UAV) Up to date, there is no unified mathematical expression that defines all VIs due to the complexity of different light spectra combinations, instrumentation, platforms, and resolutions used Therefore, customized algorithms have been developed and tested against a variety of applications according to specific mathematical expressions that combine visible light radiation, mainly green spectra region, from vegetation, and nonvisible spectra to obtain proxy quantifications of the vegetation surface In the real-world applications, optimization VIs are usually tailored to the specific application requirements coupled with appropriate validation tools and methodologies in the ground The present study introduces the spectral characteristics of vegetation and summarizes the development of VIs and the advantages and disadvantages from different indices developed This paper reviews more than 100 VIs, discussing their specific applicability and representativeness according to the vegetation of interest, environment, and implementation precision Predictably, research, and development of VIs, which are based on hyperspectral and UAV platforms, would have a wide applicability in different areas
1,190 citations
TL;DR: In this article, the authors proposed the vegetation index/temperature trapezoid, which combines spectral vegetation indices with composite surface temperature measurements to allow application of the crop water stress index (CWSI) theory to partially-vegetated fields without knowledge of foliage temperature.
1,137 citations
TL;DR: In this paper, several experiments involving the measurement of foliage-air temperature differentials (TF-TA) and air vapor pressure deficits (VPD) were conducted on squash, alfalfa, and soybean crops at Tempe and Mesa, Arizona; Manhattan, Kansas; Lincoln, Nebraska; St Paul, Minnesota; and Fargo, North Dakota.
1,094 citations