Effect of application time of polyphosphate slow release fertilizer and humic acid on some agronomic characteristics of corn (Hybrid AS 71)

In order to effect of application time of polyphosphate slow release fertilizer (PSRF) and humic acid on some agronomic characteristics of corn (Hybrid AS 71), an experiment was carried out with factorial based on randomized complete block design (RCBD), with three replications in Gotvand, during 2017-2018. The first factor included polyphosphate slow release fertilizers application time in four levels (leafy 4, leafy8, before the emergence of tassels, milky grain) and the second factor was humic acid application time at four levels (leafy 4, leafy8, before the emergence of tassels, milky grain). The results of experiment showed significant differences in main effect and interaction of experimental factors on all the studied characteristics. The highest amount of characteristics were used PSRF + humic acid in stages leafy 4 and leafy 8, and the least amount in most characteristics was observed with the application of PSRF + humic acid in the milk grain stage. The results of experiment showed , simultaneous application of PSRF + humic acid, especially, in the early stages of growth, due to suitable providing of elemental nutrients at the beginning of plant growth can lead to increased yield and components yield of Corn.