Precise Yield Estimation through Improvised CASA Model by Development of Soil and Atmospheric Constants (Sᵮ) and (Aþ)
Precise Yield Estimation through Improvised CASA Model by Development of Soil and Atmospheric Constants (Sᵮ) and (Aþ)
Rao Mansor Ali Khan* and Syed Amer Mahmood
ABSTRACT
Net Primary Production (NPP) is an indicator that is widely used to determine the supply of food and wood. NPP incorporates almost all factors that participate in the growth and development of a particular crop. These factors include various heat fluxes (e.g., ground, sensible and latent heat flux), a variety of radiations (e.g., extraterrestrial, shortwave, longwave, and net radiations), and the photosynthesis index. In this research, the net radiations were estimated as 27,428 Wm−2 throughout the wheat growth period (WGP), including (118.3 Wm−2) as shortwave and (34.63 Wm−2) as longwave radiation. Latent, soil and latent heat fluxes were estimated as 3324 Wm−2, 16,549 Wm−2, and 7554 Wm−2, respectively. Water stress during the complete WGP ranged between 0.5838 and 0.1218 from the start to the end of the cultivation period. The biomass creation was estimated as6.09–1.03 g/m2 /day, which was higher at the start of WGP than declined at the end. Finally, the estimated yield was very different as compared to the actual yield. The yield estimated through the CASA(Carnegie–Ames–Stanford approach) model was uniform for the complete study site; however, the actual yield was about 74% less than CASA generated yield in various plots. This issue was further investigated and found that the CASA model lacks various aspects. These aspects include soil suitability parameters, including pH, Organic matter, CaCO3, texture, and Electric Conductivity. The largest gap inthe CASA model, which affected the overall productivity of wheat, was the smog/haze factor which was not incorporated. The environmental factors include Black Carbon (BC), Carbon monoxide (CO), Nitrogen dioxide (NO2), Ozone (O3), and Sulphur dioxide (SO2). To cater to these issues, two indicators were developed to incorporate the smog and soil-related issues. These indicators are named Soil Factor (Sᵮ) and Atmospheric Factor (Aþ). If the soil is “Not Suitable,” the values of Sᵮ is 0.147, for less suitable soil Sᵮ is 0.21, for moderately suitable soil, Sᵮ is 0.61, and for highly suitable soil, Sᵮ is 0.95. By substituting these values of Sᵮ, the overall results approach to actual yield by 96%. The other factor Aþ is based on incorporating the situation of Atmospheric conditions faced by the wheat crop canopy, whichinclude Black Carbon (BC), Carbon monoxide (CO), Nitrogen dioxide (NO2), Ozone (O3), and Sulphur dioxide (SO2) parameters. If the overall air quality is conducive, the value of Aþ is near 1. The results obtained through the improved CASA model by the addition of Sᵮ and Aþ provided a very accurate yield that was near to actual estimates.This study is important to obtain precise estimates of cereal crops incorporating physio-climatic factor that leads toward precision agriculture.
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