Canopy nitrogen (N) status relates strongly to canopy chlorophyll content and the strength of green color. Proximal photograph by RGB camera was used to select green features that has the potential to assess N content at leaf of plant as a function of its the greenness. We proposed the development of it as a tool for sensing nitrogen content in spring wheat (Triticum aestivum). Image processing algorithm was programed calibrated and validated wheat %N%N. Nitrogen uptake =%N × canopy dry matter was harvested and calculated using simulated dry matter by DSSAT model. The data replicated laboratory measurements. A linear Lab vs Camera model displayed a unit slope with r² = 0.93. Increase of dry matter was successfully surrogated by days after emergence and used as abscissa for inverse logistic model of critical nitrogen level. It decreased gradually from about 6% to 2% as days after emergence increased from 0 to 110 days. Maximum N uptake calculated from photo and laboratory was 324 Kg ha⁻¹ and 318 Kg ha⁻¹ respectively suggesting insignificant difference. Physiological N-use efficiency (i.e., canopy weight/N weight) was 52 and 78 kg canopy dry weight per 1 kg N for early and late-ripening cultivars, respectively. The determination of N application based on the smartphone photograph proved to be useful by saving on time and expenses for growers who have access to smartphones and can use them for N application and management.

The spectral properties of the structural function of atmospheric turbulence can differ in the vertical and horizontal directions. Taking into account the influence of this anisotropy on the signal along the direction of propagation at an angle γ, to the horizon, can be useful in modeling and interpreting results of measurements. Usually when modeling the propagation of an electromagnetic signal in the anisotropic turbulent atmosphere, the effective anisotropic parameter η, is introduced. In the latter case, the dependence of the wave vector is given by the expression k =√ηk2p + k2z , where kz is a vertical component of k, and kp is horizontal. However, the spectral index of the structural function, α, remains constant and independent of γ. Here, we consider the structural function of atmospheric turbulence with dependence on the propagation angle γ. Existing experimental data show that the spectral index α. is a function of height and γ. The dependence of the α parameter on γ is introduced and it is determined from experimental measurements of atmospheric turbulent spectra. As an example of using the proposed approach, we present the results of calculations of the log-amplitude variance and propagation of a Gaussian beam through the anisotropic turbulent atmosphere.