Drop Size Distribution and Effective Determination of the Constitution of Throughfall Droplets under Maize Canopy

Abstract

Sprinkler irrigation has dominated the irrigation erosion, and droplet diameter is an important determinant. To clarify the influence of maize canopy and sprinkler droplets landing angle on drop size distribution, distribution trend, and throughfall droplets diameters, the information on droplet size and velocity are collected via 2D‐video‐disdrometer. The results showed that due to the presence of maize canopy and the decrease in landing angle, the proportion of the tiny droplets (<2 mm) within throughfall increased. Throughfall droplet size distribution under maize canopy exhibited a distinct bimodal trend, however, the new droplet volume ratio is greater when the droplet size is smaller. In addition, the trend‐line of throughfall droplet size distribution gradually shifted toward the origin as the landing angle decreased. Because of maize canopy and gradual decrease in the landing angle, throughfall droplets diameters decreased. When the droplets are <2 mm, their volume proportion is greater than that in the absence of maize canopy because of the fragmentation of large droplets. Affected by the convergence of small droplets on maize leaves, the diameter of drips generated from maize leaves in this study probably ranged from 2–5 mm. Drops >5.01 mm maight have originated from direct throughfall.

Effects of the growing-maize canopy and irrigation characteristics on the ability to funnel sprinkler water

“…As shown in supplemental materials, this study placed the needle vertically to achieve the scattering of sprinkler droplets, and the sprinkler water could be sprayed upward. The vertical falling of sprinkler water droplets could avoid the effect of landing angle on the ability of crop canopy to funnel sprinkler water because our previous work showed that the chance of their contact with corn canopy would be greater with the smaller landing angle (Zhu et al, 2021(Zhu et al, , 2022. In addition, three-needle diameters (0.70, 2.00, and 2.80 mm) were tested to regulate droplet diameter.…”