在石灰性土壤上硫酸亚铁防治苹果黄叶病的研究

果树黄叶病(失绿症)是由于缺铁而引起的生理病害。这种病害在我国西北、华北等地区发病相当普遍,有的果园发病率竟达20%—60%,病重者甚至死亡。用无机铁盐来防治这种病害,迄今已有一百多年的历史了。但用硫酸亚铁来防治黄叶病的效果并不令人满意。

STUDIES ON THE APPLICATION OF FERROUS SULPHATE FOR CONTROLLING CHLOROSIS OF APPLE TREE ON THE CALCIUM SOILS

1. The regularities of the transformation of the ferrous sulphate in the soils and organic manure, and the mechanisms of the effect of ferrous sulphate on controlling chlorosis of apple tree were studied. 2. The chlorosis of apple tree was cured rapidly by the application of 2% ferrous sulphate solution to the roots in hole, at a rate of 60 liters per tree. The curative effect lasted a month.3. By application of a mixture of ferrous sulphate and organic manure in the ratio 1:20 (or 1:10;1:5) to the roots in hole, at the rate of 22.5 kilograms per tree, the chlorosis of large apple tree was cured after a month. The curative effect lasted about a year. Injuries occured by watering after the treatment with the mixture in the ratio 1:5. 4. Favorable effect was acquired in hole application of mixture of ferrous sulphate and organic manure in the ratio 1:20 (or 1:10) at the rate of 22.5 kilograms per tree after the application of 2% ferrous sulphate solution 60 liters per tree. The curative effect of this method lasted about a year. 5. The application of manure alone to the root zone was ineffective under our experimental conditions.