Abstract: Simulated Mn deficient soil column studies with wheat show that the Mn deficient symptom, grain yield, root system distribution and Mn content of two genotypes (Chuanmai 22 and genotype 3317) were greatly affected by Mn application depth. The yields of both genotypes were obviously increased with the application depth of Mn fertilizer, and the increment of Chuanmai 22 was higher than genotype 3317. It was suggested that the higher tolerance to Mn deficiency of genotype 3317 than Chuanmai 22 was related to the higher percentage of its roots distributing in the middle and lower soil layers and to the stronger capacity of absorbing Mn from soil. It was also found that the Mn deficient symptoms of wheat at seedling stage could be disappeared after Mn fertilizer was applied at mid late stage in the middle and lower soil layers, indicating that applying Mn fertilizer at mid late stage played an important role to the formation of wheat yields.

Key words: Mn application depth, Wheat genotype, Tolerance to Mn deficiency, apple orchard soil, fertilizing regime, orchard planting age, exchangeable calcium, water-soluble calcium, calcium carbonate