Aims

Abandoned agricultural land may be used for tree plantations. This study aimed at quantifying the effects on soil chemistry almost one decade after planting. The results can contribute to the understanding of plant-soil interactions at afforestation.

Methods

An experiment including birch, hybrid aspen, larch, poplar and spruce was established at four former arable sites in Sweden. Soil samples were collected repeatedly.

Results

Common for all species were decreases in soil organic carbon (SOC) pools by 13–20 Mg ha⁻¹ or 12–18% that may be associated with former land-use and initial SOC storage. Total N pools decreased by 1.0–1.2 Mg ha⁻¹ or 13–15%, plant-available P and Ca pools decreased by 16–26% and 14–20%, respectively. Soil CN ratios were mostly unchanged. Increases in K and Mg in upper soil (0–10 cm) and unchanged or decreased levels in lower soil (10–30 cm) suggests a redistribution by plant uptake and recycling through litter decomposition. The total K pool (0–30 cm) increased the most under larch (59%) and differed significantly from that of poplar and spruce. The pH showed a declining trend. Litter CN ratios varied among species and sites.

Conclusions

We concluded that these early effects on soil chemistry were mainly due to cessation of annual management measures, increased nutrient uptake and altered soil physical conditions, like humidity and temperature, in the growing tree plantations. Few effects of different species could be observed at this stage.

中文翻译：

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五种树种造林试验中土壤化学的变化

目的

废弃的农业用地可用于植树。这项研究旨在量化种植后近十年对土壤化学的影响。研究结果有助于理解造林时植物与土壤的相互作用。

方法

在瑞典的四个前耕地建立了包括桦木，杂交白杨，落叶松，白杨和云杉的试验。重复收集土壤样品。

结果

所有物种的共同点是土壤有机碳（SOC）库减少13–20 Mg ha ^-1或12–18％，这可能与以前的土地利用和最初的SOC储存有关。总氮库减少了1.0–1.2 Mg ha ^-1或13–15％，植物可用磷库和钙库分别减少了16–26％和14–20％。土壤CN比率基本不变。上部土壤（0–10 cm）中钾和镁的增加以及下部土壤（10–30 cm）中水平的不变或下降表明植物吸收后的再分配和凋落物分解后的再循环。落叶松下的总钾库（0–30 cm）增幅最大（59％），与杨树和云杉的钾库差异显着。pH显示下降趋势。凋落物CN比率随物种和地点的不同而不同。

结论

我们得出的结论是，这些对土壤化学的早期影响主要是由于正在种植的人工林停止了年度管理措施，养分吸收增加以及土壤物理条件（例如湿度和温度）发生了变化。在这个阶段几乎没有观察到不同物种的影响。