the effect of urea fertilization method and moisture content at harvest time on mechanical properties of dried corn

mechanical properties of grain are influenced by various factors including soil nutrients and grain moisture content at harvest time. in order to reduce mechanical losses, the design of different processing operations should be performed based on the knowledge of factors influencing the mechanical properties. the effects of urea fertilization methods and grain moisture content at harvest time on mechanical properties of dried corn were investigated in a field experiment as a strip split plot with four replications based on randomized complete block design at khorram abad agricultural research station in 2010. the investigated factors were urea fertilization methods (urea foliar application and urea side-dress application), grain moisture content at harvest time (20, 30 and 40%) and four corn hybrids (ns 640, konsur 580, jeta 600 and control sc 704). the moisture content of dried grains due to different absorption property of the treatments was about 7±1 percent. the results showed that the interaction of fertilization methods and hybrid was significant (p < 0.05) for grain toughness. however, the grain moisture content at harvest time had significant effect on all studied traits except on grain firmness. the highest maximum fracture force, displacement at the maximum rupture force, energy consumption at maximum force point, specific deformation, rupture power and toughness were obtained at 20% grain’s moisture content also, the results showed that ns hybrid had the highest maximum rupture force (219 n), displacement at the maximum fracture force (0.37 mm), energy consumption at maximum force (42.51 mj), rupture power (3.89 . 10-3w) and toughness (0.33 mj mm-3).