Germination and seedling emergence of green bean and maize in different soil depths and physical characteristics

A field study was carried out to investigate the effects of four planting depths and three soil types with different physical characteristics on green bean (Phaseolus vulgaris Var. sunray) and maize (Zea mays L. Var. Amyla) seed germination and seedling emergence.The aim of the experiments was to investigate the physical effects of the soil on seed ecology and emergence dynamics. The result revealed that germination inhibition was directly proportional to clay content and inversely proportional to sand content due to burial depth. Depth of fifty percent emergence inhibition (Di50%) were equal to 5.3 cm in clay soil for both green bean and maize, if this was for silty soil, respectively 5.4 and 2.7 cm. A significant linear regression between clay particle content and Di50% revealed that those soil components had opposite effects in terms of favoring or inhibiting depth mediated inhibition. Therefore, increasing soil clay contents increased inhibition of seedlings. The data also showed that the oxygen content in the surrounding soil of seeds can not be an important factor for seed germination differences, and its effect was insignificant. Increasing geometric mean decreased particle diameter soil inhibition. In conclusion, these experiments showed soil physical properties had a strong effect on buried-seed ecology and consequently on seed germination and seedling emergence.