问题 问答题 简答题

如何防治香樟黄化病?

答案

参考答案:(1)栽植地应选排水良好,微酸性肥沃的土壤。(2)在患病植株根际周围打孔,浇灌30-50倍硫酸亚铁,或用硫酸亚铁1000倍叶面喷施2-3次,可使叶转色。(3)在树杆注射硫酸亚铁15g

问答题

凡尔赛——华盛顿体系对国际关系及欧美各国的发展有何积极作用?它引起或加剧了哪些矛盾?这些矛盾在以后的历史发展中造成了怎样的结果?为什么说凡尔赛——华盛顿体系必然走向崩溃?

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