2.1. Plant material and growth conditions
Two field experiments were performed in a clay loam soil with
pH 7.7 at a private farm located in Belqas district, Dakahlia Governorate,
Egypt (latitude 31◦12
47 N, longitude 31◦21
27 E and
altitude 13 m above sea level), during the two seasons of 2011
and 2012, using the dry bean cv. Nebraska to achieve the study
objectives. The soil contained 0.82 ppm of Zn. Air temperatures