ALBERT

Description: Soil temperature plays a vital role in determining crop yield. Excessive irrigation may result in low soil temperature and a waste of water resources. In this paper, field experiments were carried out to evaluate the influence of irrigation methods and biochar application on soil temperature. The experiment included six treatments: (a) YB: biochar application in border irrigation with Yellow River water; (b) GB: biochar application in border irrigation with groundwater; (c) DB: biochar application in drip irrigation with groundwater; (d) Y(CK): border irrigation with Yellow River water; (e) G(CK): border irrigation with groundwater; (f) D(CK): drip irrigation with groundwater. The results are as follows: coupling drip irrigation and biochar, soil temperature increased by 1.20–3.87%. In the biochar application in border irrigation with Yellow River water and groundwater, soil temperature increased by 0.80–2.40% and 1.01–5.15%, respectively. Biochar is a medium for reducing the heat exchange of soil and atmosphere, as it hinders bi-directional heat movement. This mechanism was especially apparent at a 0–10 cm soil depth in the treatments of border irrigation using Yellow River water and groundwater. Biochar may help stabilize the fluctuation of soil temperature and improve the soil accumulated temperature. The effect of drip irrigation at 5–10 cm depth, border irrigation using the groundwater and the Yellow River water was great on soil temperatures above the 10 cm level but less on deep soil temperatures. After applying biochar to soil, the soil temperature was more sensitive to external temperature changes, such as air temperature and water temperature. Therefore, in the Hetao irrigation area, applying a proper amount of biochar to farmland soil was shown to improve the water and heat environment and improve the effectiveness of traditional border irrigation in synchronizing water and heat, especially under the drip irrigation condition. The results here suggest that using biochar under drip irrigation can promote growth and increase yield.

Description: Based on the Monte Carlo (MC) algorithm, we simulate the evolutions of different types of the polarized lights in the broad-band range from visible to infrared in foggy environments. Here, we have constructed two scattering systems to simulate the transmission characteristics of the polarized lights: (1) A monodisperse system based on five types of particles with the sizes of 0.5, 1.0, 2.5, 4, and 5 µm, respectively; (2) a polydisperse system based on scattering particles with a mean value (size) of 2.0 μm. Our simulation results show that linearly polarized light (LPL) and circularly polarized light (CPL) exhibit different advantages in different wavelengths and different scattering systems. The polarization maintenances (PM) of the degree of circular polarizations (DoCPs) are better than those of the degree of linear polarizations (DoLPs) for most incident wavelengths. CPL is not superior to LPL in the strong-absorption wavelengths of 3.0µm, 6.0µm, and long infrared. Here, when the wavelength is closer to the particle sizes in a system, the influence on propagating polarizations will be more obvious. However, the difference in the degree of polarization (DoP) between the resulting CPL and LPL is positive at these points, which means the penetrating ability of CPL is superior to that of LPL in these scattering systems. We have also simulated the extinction efficiency Qext and the scattering index ratio Qratio as functions of both wavelength and particle size for analyzing polarization’s transmission characteristics. Our work paves the way of selecting the optimal incident wavelengths and polarizations for concrete scattering systems.