State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi, China.
PLoS One. 2013 Aug 5;8(8):e71923. doi: 10.1371/journal.pone.0071923. Print 2013.
The revegetation of abandoned farmland significantly influences soil organic C (SOC) and total N (TN). However, the dynamics of both soil OC and N storage following the abandonment of farmland are not well understood. To learn more about soil C and N storages dynamics 30 years after the conversion of farmland to grassland, we measured SOC and TN content in paired grassland and farmland sites in the Zhifanggou watershed on the Loess Plateau, China. The grassland sites were established on farmland abandoned for 1, 7, 13, 20, and 30 years. Top soil OC and TN were higher in older grassland, especially in the 0-5 cm soil depths; deeper soil OC and TN was lower in younger grasslands (<20 yr), and higher in older grasslands (30 yr). Soil OC and N storage (0-100 cm) was significantly lower in the younger grasslands (<20 yr), had increased in the older grasslands (30 yr), and at 30 years SOC had increased to pre-abandonment levels. For a thirty year period following abandonment the soil C/N value remained at 10. Our results indicate that soil C and TN were significantly and positively correlated, indicating that studies on the storage of soil OC and TN needs to focus on deeper soil and not be restricted to the uppermost (0-30 cm) soil levels.
耕地废弃后，其土壤有机碳（SOC）和总氮（TN）会显著增加。然而，耕地废弃后土壤 OC 和 N 储存的动态变化仍不清楚。为了更多地了解耕地废弃 30 年后土壤 C 和 N 储存的动态变化，我们在黄土高原纸坊沟流域的草地和农田样地中测量了 SOC 和 TN 含量。草地样地建立在废弃 1、7、13、20 和 30 年的农田上。表层土壤 OC 和 TN 在较老的草地中更高，尤其是在 0-5cm 土壤深度；较年轻的草地（<20 年）深层土壤 OC 和 TN 较低，而较老的草地（30 年）较高。较年轻的草地（<20 年）土壤 OC 和 N 储量（0-100cm）显著较低，而较老的草地（30 年）则有所增加，并且在 30 年内 SOC 增加到了废弃前的水平。废弃后 30 年内，土壤 C/N 值保持在 10。我们的结果表明，土壤 OC 和 TN 呈显著正相关，这表明研究土壤 OC 和 TN 的储存需要关注深层土壤，而不仅仅局限于最上层（0-30cm）土壤。
