Effects of potassium and zinc application on silage corn cultivation

Corn (Zea mays L.) is one of the most important agronomic crops in Iran. Potassium and zinc are two essential elements for different crops such as corn. Corn requirement to K and Zn is relatively high. In order to study effects of Zn and different amounts and sources of K the yield and quality of silage corn, in 2002, a field experiment were conducted in Karaj Soil & Water Research Station with soil K and Zn available 189 and 0.69 mg kg^-1, respectively. In this experiment, 12 fertilizer treatments including three levels of K (0, 50 and 100 kg ha^-1 K₂O), two K sources (chloride and sulfate) and two rates of Zn (0 and 10 mg kg^-1 Zn) as ZnSO₄ were compared by factorial in completely randomized block design with three replications. All of agronomic operations carried out based on research recommendations. 
      The annual results showed that Zn and K application caused increasing in silage yield (14% humidity), Zn and K concentrations and total uptakes in silage significantly (α= 0.05%). But, in general, application of both Zn and potassium together to compare with application of each element alone had better effects on silage yield and the majority of related parameters. Maximum and minimum silage yield were 17,404 and 12,080 kg ha^-1 respectively which produced from K₅₀S₂Zn₁₀ (application of 50 kg ha^-1 K₂O as SOP and 10 kg ha^-1 Zn at the same time) and control. In general, there was not significant difference between two potassium sources, although potassium sulfate had better effects.