to study the effect of planting date, plant density and planting pattern on yield of corn (zea mays l) var. ksc 647 split plot factorial experiment in a randomized complete block design with four replications at bayranshahr lorestan province in crop year 2015 was conducted. factors examined included planting date in three levels: (25 may, 12 june and 29 june), density at three levels (60, 75 an...