The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, UK.
J Environ Manage. 2012 Aug 15;104:158-65. doi: 10.1016/j.jenvman.2012.03.024. Epub 2012 Apr 10.
Carbon storage (carbon density; kg C m(2)), concentrations of dissolved organic carbon (DOC) in soil pore water and soil respiration (g C m(2) yr(-1)) were measured in a 35 year old urban lawn soil amended with a surface mulch application of green waste compost and compared to those in two newly created urban soils, manufactured by mixing different volumes of green waste compost with existing soils or soil forming materials. The aim was to determine C storage and calculate annual fluxes in two newly created urban soils compared to an existing urban soil, to establish the potential for maintaining and building carbon storage. In the lawn soil, organic carbon storage was largely limited to the upper 15 cm of the soil, with material below 30 cm consisting of substantial amounts of alkaline building debris augmenting sandstone parent material. Leaching of DOC directly from the surface applied compost mulch amendment was readily mobile within the upper 15 cm of soil beneath, but not to 30 cm depth, indicating limited vertical redistribution of the soluble organic C fraction to the deeper, technic horizons. Only a very small proportion of annual C losses were attributable to DOC export (≤ 0.5%) whilst a much greater amount was accounted for by soil respiration (∼20%). In the two newly created urban soils, ≤ 30% additions of compost mixed with existing soil forming materials trebled C densities from <2 to 6 kg total carbon (TC) m(2), surpassing those of the existing lawn soil (≤ 5 kg TC m(2)). Adding 45% compost served only to reduce bulk density so that C densities did not increase further until >50% compost was applied. Combined increases in soil respiration losses and DOC leaching associated with higher compost application rates suggested that volumes of ∼30% compost were altogether optimal for sustainable C storage whilst minimising annual losses. Thus repeated applications of small amounts, rather than single applications of large amounts of green waste compost could be most effective at maintaining and building C storage in urban soils.
碳储量（碳密度；kg C m(-2)）、土壤孔隙水中溶解有机碳（DOC）浓度和土壤呼吸（g C m(-2) yr(-1))）在 35 年生的城市草坪土壤中进行了测量，该土壤用表面覆盖的绿肥堆肥进行了施肥，并与两种新创建的城市土壤进行了比较，这两种城市土壤是通过混合不同体积的绿肥堆肥与现有土壤或土壤形成材料制成的。目的是确定两种新创建的城市土壤与现有城市土壤相比的碳储量和计算年通量，以确定维持和增加碳储量的潜力。在草坪土壤中，有机碳储量主要局限于土壤上层 15cm 以内，30cm 以下的物质主要是大量碱性建筑碎片，增加了砂岩母质。直接从表面施用的堆肥覆盖物中淋滤出的 DOC 在土壤上层 15cm 以下很容易移动，但不会移动到 30cm 深度，表明可溶有机 C 部分向更深的技术层的垂直再分配有限。只有很小一部分（≤0.5%）的年碳损失归因于 DOC 输出，而更多的碳损失归因于土壤呼吸（∼20%）。在两种新创建的城市土壤中，将堆肥与现有土壤形成材料混合添加量达到 30%，将 C 密度从<2 倍增加到 6kg 总碳（TC）m(-2)，超过了现有草坪土壤（≤5kg TC m(-2)）。添加 45%的堆肥仅降低了容重，因此在添加>50%的堆肥之前，C 密度不会进一步增加。随着堆肥施用量的增加，土壤呼吸损失和 DOC 淋出量的增加表明，30%左右的堆肥量是可持续碳储存的最佳量，同时最大限度地减少了年损失。因此，在城市土壤中，重复施用少量而非单次施用大量绿肥堆肥可能是维持和增加碳储量最有效的方法。
