The impact of land-use change in an urban ecosystem on soil aggregate dynamics and soil carbon storage was studied through two annual cycles under five land uses. All the land uses namely: (1) natural mixed vegetation (NV) growing in a protected area; (2) grass fallow (GF); and tree plantations of (3) Cassia siamea (CP); (4) Jatropha curcas (JP); and (5) Tectona grandis (TP) were grown on urban degraded waste lands in a dry tropical region of India. Proportions of soil aggregate fractions, their stability, and soil carbon storage were analyzed at upper (00–15 cm), and lower (15–30 cm) soil depths during the rainy, winter, and summer seasons. Across all the land uses and at both the soil depths, the proportion of macroaggregate was highest during summer and lowest during the rainy season, whereas the reverse trend was observed for mesoaggregate. The annual mean proportion of macroaggregate decreased while meso- and microaggregates increased, with increasing soil depth across all the land uses. At the upper layer, the trends of macroaggregate, aggregate stability, and soil C storage were NV > CP > JP > TP > GF whereas at lower depth, the trend was NV > TP > CP > JP > GF. Across all the land uses in both the depths, soil C storage was strongly and positively correlated with annual mean fraction of soil macroaggregate. All tree plantations improved soil properties considerably as compared to GF at upper soil layer, yet TP reached near NV in these soil properties at lower depth. Soil aggregate fractions may be used as an index of carbon storage capacity in the urban ecosystems.

中文翻译：

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人工林对热带干旱地区城市退化土地土壤团聚体动态的影响

通过五个土地利用下的两个年度周期研究了城市生态系统中土地利用变化对土壤团聚体动态和土壤碳储存的影响。所有土地用途即： (1) 生长在保护区内的天然混合植被 (NV)；(2) 草地休耕（GF）；(3) Cassia siamea (CP) 的人工林；(4)麻风树(JP)；和 (5) Tectona grandis(TP) 生长在印度干旱热带地区的城市退化荒地上。在雨季、冬季和夏季期间，在上部（00-15 厘米）和下部（15-30 厘米）土壤深度分析了土壤团聚体部分的比例、稳定性和土壤碳储存。在所有土地利用和土壤深度中，大团聚体的比例在夏季最高，雨季最低，而中细团聚体的比例则相反。随着所有土地用途的土壤深度增加，大团聚体的年平均比例下降，而中小团聚体和微团聚体增加。在上层，大团聚体、团聚体稳定性和土壤碳储量趋势为 NV > CP > JP > TP > GF，而在下层，趋势为 NV > TP > CP > JP > GF。在两个深度的所有土地利用中，土壤碳储量与土壤大团聚体的年平均分数呈强正相关。与上层土壤的 GF 相比，所有人工林都显着改善了土壤特性，但在较低深度的这些土壤特性中，TP 达到了接近 NV。土壤聚集体部分可用作城市生态系统中碳储存能力的指标。