گزارش نهایی بررسی اثر مصرف گوگرد در رفع کمبود روی و آهن بر روی درختان سیب گلدن ایستگاه گلمکان (‮‭1363 - 70‬)

In this study the effect of Sulphur in eleminating the deficiency of Zinc and Iron in the Golden Apple Trees were Investigated. The experiment was done in a loam-sandy loam texture soil at Golmakan Research Station 40 Km North West of Mashhad. A randomized blocks design was used with three replicates from 1984.through 1991. In the first year, five levels of sulphur (0- 2.5- 5- 7.5- 10) Kg were applied to each tree. At the same time two levels (0- 40 Kg) of animal manure were applied and incorporated into the soil at the depth of 30 Cm around each tree every year. Two additional treatments of liguefied Zinc Sulphate at a rate of 4 gram per liter three time a year was also used at this experiment. The fallowing are concluted summary of the eight years experiment. 1- The produced sulphate from the sulphur oxidation was increasing by the addition of sulphur through out the experiment. the result was significant by one percent. Appllication of 10 Kg sulphur had the best result. 2- The soil acidity was affected by the rate of oxidation, Appli cation of 10 Kg sulphur lowered the soil origenal PH by 0.5 unit in second and third years. 3- The oxidazed sulphur was significant with accuracy of 99% and lowered amount of lime in soil Application of 10 Kg sulphur had the best result in lowering the soil lime content. The maximum effct showed in the second year, there was 25% lowering to the So treatment 4- Application of sulphur didn't have any significant effect on the Zinc level of tree leaves. 5- Application of sulphur didn't find to have any effect on the amount of Iron in leaves. However application of animal manure had affected the amount of Iron in leaves and has increased it.