Effects of cushion box and closed let-down ladder usage on damage to corn during handling: physiological deterioration

Abstract

Background Corn seeds have a high susceptibility to mechanical damage due to their large size and mass. The main purpose of this study was to evaluate the effects of the cushion box and closed let-down ladder usage in minimizing the negative influence of the free fall on the storage potential of corn seeds. Corn seeds were evaluated for the extent of physiological damage by measuring the seed deterioration by the accelerated aging test (percentage loss in germination in the accelerated aging test), using three drop methods (free fall, with cushion box, and with closed let-down ladder) at three drop heights (5, 10, and 15 m) and five different moisture contents (10, 15, 20 and 25%). Results The drop methods had a significant effect on the storage potential of corn seeds. Sample seeds dropped without a ladder (free fall) had a significantly higher average physiological quality loss of 13.87% (loss in accelerated aging germination). In the use of the cushion box, the average percentage loss in germination was calculated to be 11.38%, which was decreased by about 18% more than the free fall. Sample seeds dropped with the closed let-down ladder had a lower average percentage loss in the germination of 8.78%, which showed that the closed let-down ladder significantly helped to reduce mechanical damage to corn seeds by about 37% comparing free fall and by about 23% to the use of the cushion box. The amounts of loss in physiological quality of corn seeds increased significantly with increasing drop height and moisture content, but the use of the cushion box and closed let-down ladder systems somewhat reduced the adverse effect of the above factors. Empirical models were developed for the dependency of physiological damage to corn seeds due to the impact caused by free fall, on the drop height and moisture content at different drop methods. Conclusions To minimize mechanical damage to seeds as they fall into the bin, a let-down ladder should be installed in the bin so that it can receive seeds from the filling spout with minimum damage.

Assessing the effects of free fall conditions on damage to chickpea seeds: A comprehensive examination of seed deterioration

“…This finding suggests that chickpea seeds with lower moisture contents are more resilient to physiological damage (reduction in germination percentage) compared to those with higher moisture values, which aligns with previous studies (Khazaei et al, 2008;Shahbazi, 2021;Shahbazi et al, 2017). The higher moisture contents may have led to increased flexibility in the seed tissues, transferring impact energy to the embryo and further reducing the germination percentage, as reported by Khazaei et al (2008) for wheat, Shahbazi et al (2012) for pinto beans, and Gu et al (2019) and Shahbazi and Shahbazi (2022b) for corn seeds. Higher seed moisture content can reduce mechanical seed coat damage at harvest (Uebersax et al, 2022).…”

“…Seed deterioration is a dynamic process, with damaged areas gradually expanding to affect living embryonic tissues, leading to a decline in seed quality. Physical and physiological damage to the cell membrane is the primary cause of seed aging and deterioration, accompanied by enzymatic, respiratory, and hormonal changes, reduced protein production, genetic damage, and the accumulation of toxic metabolites (Shahbazi & Shahbazi, 2022b).…”

“…Researchers have analyzed drop tests of corn, soybean, and wheat seeds on various contact surfaces in multiple studies (Bartkowiak et al., 2019 ; Li et al., 2020 ; Shah et al., 2001 ; Shahbazi & Shahbazi, 2022a , 2022b , 2023 ). The results of these studies consistently show that the damage to seeds caused by free fall increases with the height of the fall but may decrease with moisture content and temperature.…”

Impact damage to chickpea seeds during free fall

“…As a result, the amount of damage will increase. This is due to the increasing seed velocity with drop height, which results in a larger impact force (Fiscus et al, 1971;Shahbazi and Shahbazi, 2022c). Foster and Holman (1973) reported that when the drop height was more than 15 m, the velocity of the seed stream could exceed the single kernel velocity because, when the seed stream was dropped as a whole, the drag forces on the individual seeds were not all the same.…”

“…In order to reduce the drop height and speed of falling of the seeds when they leave the conveyors or during the unloading or loading of seeds storage bins, stepping falling systems (ladders) should be used (Shah et al, 2001). Two kinds of such systems, known as the cushion box and closed let-down ladder (Gregg and Billups, 2016;Shahbazi and Shahbazi, 2022c) are commonly used. These types of equipment can be installed in the path of seed transfer pipes or in the center of seed storage bins in order to unload or load bins while preserving the desired seeds in a safe state, without damage (Gregg and Billups, 2016;Shahbazi and Shahbazi, 2022a).…”