Li Qiu Jia, Xue Zhi Jing, Zhou Zheng Chao
School of Geographical Science and Tourism, Shaanxi Normal University, Xi&rsquo.
Institute of Soil and Water Conservation, Northwest A＆F University, Yangling 712100, Shannxi, China.
Ying Yong Sheng Tai Xue Bao. 2019 Jan 20;30(1):137-145. doi: 10.13287/j.1001-9332.201901.022.
We explored the effects of vegetation restoration on the soil nutrients and microbial pro-perties of soil aggregates with different particle size by comparing soils in a natural grassland which had been restored for nearly 30 years and in cropland in the loess hilly regions of Ningxia. We analyzed the soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil basal respiration (CO-C) and respiratory quotient (qCO) of different particle size soil aggregates collected from cropland and natural grassland. The results showed that soil aggregates of natural grassland had more micro-aggregates (particle size <0.25 mm), higher nutrient concentrations (SOC, TN and available K) and C/N than that of cropland. The highest concentrations of SOC and TN in 1-2 mm aggregates and higher C/N in natural grassland and cropland suggested that vegetation restoration could improve the capacity of soil aggregates to reduce nutrient loss and accumulate organic matter, with the highest nutrient accumulation in 1-2 mm aggregates. Microbial biomass (MBC, MBN) and CO-C in natural grassland were higher than in cropland, but the qCO was significantly lower, suggesting that vegetation restoration could effectively improve soil microbial biomass and activity, and make soil habitats more stable. The magnitude of responses of the microbial characteristics of different particle aggregates to vegetation restoration varied due to the differences in nutrient characteristics. The MBC of 1-2 mm aggregates, the MBN of <0.25 mm, 0.25-1 mm and 1-2 mm aggregates, the microbial activity of 1-2 mm and >5 mm aggregates were more sensitive than the rest of the particle aggregates of vegetation restoration. In conclusion, vegetation restoration could effectively improve the fertility and structural characteristics of soil aggregates, and the most prominent improvement was in 1-2 mm particle size aggregates.
通过比较宁夏黄土丘陵区近30年植被恢复的天然草地和农田土壤，我们探究了植被恢复对不同粒径土壤团聚体的土壤养分及微生物特性的影响。我们分析了从农田和天然草地采集的不同粒径土壤团聚体的土壤有机碳（SOC）、全氮（TN）、微生物量碳（MBC）、微生物量氮（MBN）、土壤基础呼吸（CO-C）和呼吸商（qCO）。结果表明，天然草地的土壤团聚体有更多的微团聚体（粒径<0.25毫米），养分浓度（SOC、TN和速效钾）和碳氮比高于农田。1-2毫米团聚体中SOC和TN浓度最高，天然草地和农田中碳氮比更高，这表明植被恢复可以提高土壤团聚体减少养分流失和积累有机质的能力，1-2毫米团聚体中养分积累最高。天然草地的微生物量（MBC、MBN）和CO-C高于农田，但qCO显著更低，这表明植被恢复可以有效提高土壤微生物量和活性，并使土壤生境更稳定。由于养分特性的差异，不同粒径团聚体的微生物特性对植被恢复的响应程度各不相同。1-2毫米团聚体的MBC、<0.25毫米、0.25-1毫米和1-2毫米团聚体的MBN、1-2毫米和>5毫米团聚体的微生物活性比其他粒径团聚体对植被恢复更敏感。总之，植被恢复可以有效改善土壤团聚体的肥力和结构特性，最显著的改善是在1-2毫米粒径的团聚体中。
