effect of manure and foliar application of zinc and manganese on yield and yield components in soybeans (glycine max l., var. williams)

in order to study the effect of different levels of the manure and foliar application of zn and mn fertilizers on the quantitative and qualitative yield of soybeans (var. williams), a factorial experiment was conducted in a randomized complete block design with three replications in 2012. treatments involved three levels of fertilizer: manure (zero as control; six and 12 t/ha), two levels of mn (zero-control; three g/l) and zn (zero as control; three g/l). the traits studied were the number of pods on the plant, number of grains in a pod, 100 grain weight, percentage of grain oil, percentage of grain protein, height, chlorophyll content, grain yield, biological yield, and harvest index. results showed that biological yield, plant height, and grain yield were significantly affected by the application of manure, mn, and zn, respectively. manure × mn × zn interaction had a significant influence on percentage of grain oil and protein. when the control treatment was applied in the absence of mn, the maximum plant height was 39.92 cm, maximum grain yield was about 59.167 g/m2, and harvest index was about 23.33%. the lowest harvest index value was observed for six t/ha manure and no mn (14.5). the maximum percentage of grain oil and protein were obtained for six t/ha manure applied with the foliar application of zn and mn (26.63 and 37.3%, respectively). the minimum oil percentage was obtained for no manure, no zn and mn (16%). the results indicated that six t/ha manure application followed by foliar application of mn and zn is the most suitable fertilization treatment for good growth of soybeans var. williams in the same conditions of this experiment.