Effects of Soil Application of Zinc Sulfate and Immersing of Seedling Roots in Zinc Oxide Suspension on Yield and Chemical Composition of Rice (CV. Ghasrodashti)

Zinc deficiency in rice has been reported from all over the world, especially in calcareous soils. One of the corrective methods is application of zinc fertilizers. Considering calcareous condition of paddy soils in Fars Province and in order to compare soil application of zinc sulfate with immersing of seedling roots in zinc oxide suspension on yield and chemical composition of rice ( CV Ghasrodashti), two experiments were conducted during two years. Each test was performed in the form of RCB design with four replications.. In the first experiment, the effect of soil application of ZnSO₄.7H₂O was studied at the rates of 0, 5, 10 and 15 kg Zn/ha, while in the second experiment, immersing for 30 minutes of seedling roots in suspension containing 0, 1 and 2 percent zinc oxide, was tested before transplanting. The results showed that application of ZnSO₄.7H₂O in the first year had   significant effect (at 5% level) on the number of grain per spike, grain P content and the Zn content of husk, but was highly significant effect ( at1% level) on grain protein content. In the second year, application of different rates of zinc sulfate had a significant effect (5%) on N, K and number of grain per spike but highly significant effect (1%) on Mn contents of rice grain. The effect of immersing in suspension of zinc oxide in the first year of experiment had significant effect (5%) on zinc and the protein content of grain but highly significant effect (1%) on N content of grain. In the second year the effect of zinc oxide on grain yield, N, K and protein content of grain was significant (5%). The ANOV of 2 years data showed that the effect of ZnSO₄.7H₂O on grain yield, number of grain per spike, N and P was significant (5%) but was highly significant (1%) on protein content of grain. The effect of zinc oxide on 1000 kernel weight and protein content were significant at 5 and 1% level, respectively. The final conclusion is that, application of Zn in paddy fields of Fars province is essential, but with regard to the fertilizer source and amounts, further study is needed.