Background: Little is known about the relationship between plant availability of P in different sludges and their derived ashes, its development over time and its interaction with soil pH.

中文翻译：

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pH值相反的土壤中污泥和灰烬的磷有效性

背景：关于不同污泥中磷的植物有效性及其衍生的灰分，其随时间的发展以及与土壤pH的相互作用之间的关系鲜为人知。