Key Message

The acceleration of K release in the eucalyptus rhizosphere is a key process for explaining plant K uptake in low-K tropical soils.

Abstract

We conducted a pot experiment to evaluate the short-term dynamics of soil K at the soil-root interface of eucalyptus plants. We hypothesized that eucalyptus roots are able to substantially modify the soil K supply by releasing K from more recalcitrant K pools. To test our hypothesis, we used five tropical Oxisols in which the remaining structural K forms were components of highly weathering-resistant minerals. The experiment was installed in a split-plot arrangement of treatments in a randomized block design with four replicates. The effect of the soils was studied in the main plots. In the subplots, we isolated or did not isolate eucalyptus roots from the soil. At the end of the experiment, we determined the total soil K, exchangeable K, and K extracted with Mehlich 1 (M1) and Mehlich 3 (M3) as well as the K content in plant shoots. Our main findings suggest that the acceleration of K release in the eucalyptus rhizosphere is a key process for explaining plant K uptake in low-K tropical soils. Understanding and quantifying the processes related to this phenomenon are necessary to provide a more mechanistic basis for K fertilization recommendations as well as to monitor the sustainability of natural and planted eucalypt forests

中文翻译：

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桉树根际土壤钾动态

关键信息

桉树根际 K 释放的加速是解释低 K 热带土壤中植物 K 吸收的关键过程。

抽象的

我们进行了盆栽试验，以评估桉树植物土壤-根系界面处土壤 K 的短期动态。我们假设桉树根能够通过从更顽固的钾池中释放钾来显着改变土壤的钾供应。为了检验我们的假设，我们使用了五种热带氧化溶胶，其中剩余的结构性 K 形式是高度抗风化矿物的组成部分。该实验采用随机区组设计的裂区处理布置，具有四个重复。在主要地块中研究了土壤的影响。在子地块中，我们从土壤中分离或不分离桉树根。在实验结束时，我们确定了土壤总钾、可交换钾和用 Mehlich 1 (M1) 和 Mehlich 3 (M3) 提取的 K 以及植物芽中的 K 含量。我们的主要发现表明，桉树根际 K 释放的加速是解释低 K 热带土壤中植物 K 吸收的关键过程。了解和量化与这种现象相关的过程对于为钾肥施肥建议提供更机械的基础以及监测天然和人工桉树林的可持续性是必要的