城市化导致不透水表面的快速扩张,因此,更好地了解土壤封闭的生物地球化学后果至关重要。先前的研究记录了土壤碳和氮含量的显着降低,然而,目前尚不清楚这种减少是否是表层土壤去除或长期土壤密封的结果。在这项研究中,在两个深度(0-10厘米,和10-20厘米)。所有的家园,11-114岁,在阿拉巴马州和佐治亚州的皮埃蒙特地区采样,美国。这个年龄范围使得能够使用时间序列方法来估计采样房屋下的碳损失或增加。房屋和相邻城市草坪下的土壤碳含量差异与年龄呈二次关系。最大C损失发生在大约五十年。对于MBC:C比率观察到相同的模式,这表明土壤碳含量在房屋下方下降了50年,然后增加。前10厘米土壤平均C和N含量分别为61.86%(±4.42%),与城市草坪相比,房屋下方的房屋降低了65.77%(±5.65%)。微生物生物量碳(MBC),与城市草坪相比,房屋下方的氮(MBN)显着降低,而房屋下方的堆积密度和磷含量较高。
Urbanization results in the rapid expansion of impervious surfaces, therefore a better understanding of biogeochemical consequences of soil sealing is crucial. Previous research documents a significant reduction in soil carbon and nitrogen content, however, it is unclear if this decrease is a result of top soil removal or long-term soil sealing. In this study, soil biogeochemical properties were quantified beneath homes built on a crawl space at two depths (0-10 cm, and 10-20 cm). All homes, 11-114 years in age, were sampled in the Piedmont region of Alabama and Georgia, USA. This age range enabled the use of a chronosequence approach to estimate carbon loss or gain under the sampled homes. The difference in soil carbon content beneath homes and adjoining urban lawns showed a quadratic relation with age. Maximum C loss occurred at approximately fifty years. The same pattern was observed for MBC: C ratio suggesting that the soil carbon content was decreasing beneath the homes for first fifty years, then increased afterward. The average soil C and N content in the top 10 cm were respectively 61.86% (±4.42%), and 65.77% (±5.65%) lower underneath the homes in comparison to urban lawns. Microbial biomass carbon (MBC), and nitrogen (MBN) were significantly lower below the homes compared to the urban lawns, while bulk density and phosphorus content were higher beneath the homes.