Trees impact the chemical properties of the soil in which they grow. When planting forests, the choice of tree species and species combinations is thus expected to partly determine the spatial variation in soil properties, even in the early stages of forest development. We made use of a biodiversity-ecosystem functioning experiment in Belgium, FORBIO (FORest BIOdiversity and Ecosystem Functioning). The studied site is situated on former agricultural land on loamy sandy soil and replicates tree species richness (1–4 species) and composition. Soil samples (0–10 cm) were taken at five locations in 1, 2 and 4 species plots. We measured the total C and N concentration, the Olsen P, the pH-H₂O and the available Ca, Mg and K concentration. We hypothesised that the within-plot spatial variability would increase with species richness and that the between-plot variability would decrease with species richness. We found little evidence to support our hypothesis. We only found a smaller within-plot variability in monocultures than mixtures for Ca, pH and C:N. Potential reasons for the little evidence for the effect of tree species richness may include the fact that the forest is only 9 years old, the agricultural land-use history and the soil texture. Further research in sites with different soil properties or different land-use history is needed to generalise these results.

中文翻译：

---

树种丰富度对年轻人工林土壤化学特性的样地内和样地间变异性影响不大

树木会影响它们生长的土壤的化学性质。因此，在植树造林时，树种和树种组合的选择有望部分决定土壤性质的空间变化，即使在森林发展的早期阶段也是如此。我们利用了比利时的生物多样性生态系统功能实验 FORBIO（森林生物多样性和生态系统功能）。研究地点位于肥沃沙土上的前农业用地上，复制了树种的丰富度（1-4 种）和组成。在 1、2 和 4 个物种地块的五个位置采集土壤样本（0-10 厘米）。我们测量了总 C 和 N 浓度、Olsen P、pH-H ₂O 和可用的 Ca、Mg 和 K 浓度。我们假设地块内的空间变异性会随着物种的丰富度而增加，而地块间的变异性会随着物种的丰富度而降低。我们发现几乎没有证据支持我们的假设。我们只发现单一培养物中的小区内变异性小于 Ca、pH 和 C:N 的混合物。没有证据表明树种丰富度影响的潜在原因可能包括森林只有 9 年的历史、农业用地历史和土壤质地。需要对具有不同土壤性质或不同土地利用历史的地点进行进一步研究，以推广这些结果。