Effects of Fe, Mn, Zn and Cu fertilization on the yield and grain quality of wheat in the calcareous soils of Iran

In order to study the effects of micronutrients on wheat production in calcareous soils, 25 field experiments with wheat were conducted in the Dorodzan region, about 50 km west of Shiraz in south of Iran in 1998–99. Five fertiliser treatments including control (nitrogen, phosphorous and potassium based on soil tests), control + Fe, control + Mn, control + Zn and control + Cu were tested in a completely randomized block design with three replications. The soils of the selected fields contained high amounts of calcium carbonate equivalent (31–40%). The results showed that Fe, Mn, Zn and Cu fertilisation caused significant increase in grain yield, straw yield, 1000 grain weight, and the number of seeds per spiklet. With the application of these nutrients, their concentration and total uptake in grain and flag leaves and the grain protein content increased significantly. Based on the DTPA method, the critical soil levels were found to be 4.3 mg kg−1 for Fe and Mn and 0.9 mg kg−1 for Zn and Cu.