State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, China; Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, 848300, Cele, China; University of Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, China; Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, 848300, Cele, China; Institute of Arid Agroecology, School of Life Sciences, State Key Laboratory of Grassland Agro-ecosystems, Lanzhou University, 730000, Lanzhou, China.
J Environ Manage. 2020 Jun 1;263:110373. doi: 10.1016/j.jenvman.2020.110373. Epub 2020 Mar 25.
Long-term data regarding soil properties and crop growth are powerful resources substantially contributing to our knowledge of soil-forming processes of reclaimed sandy desertification land. Generalized ecological principles derived from long-term observations that help to maintain or improve soil quality and productivity is critical for guiding field management practices while suitable for newly reclaimed sandy desertification land still need to be evaluated. Here, a 14-yr old experiment showed that soil quality index (SQI) had an "increase-decline-recovery" tendency in irrigation and fertilizer addition desertification lands while it remained at constantly low levels in desertification land with only irrigation. Stably decent yield and net incomes were obtained after 3-4 years' consecutive irrigation and fertilizer addition management. Correlation between crop productivity and SQI followed a saturation characteristic curve with threshold at 0.5, corresponding to soil organic carbon (SOC) ~5.0 g kg, below which crop productivity was linearly declined. 60% of observed inter-annual variations in SQI were explained by quantity of leaf litter, which was three times higher than explanatory power of root residue. No substantial changes occurred in soil mechanical components while the soil microbial biomass carbon, water-stable aggregate and heavy carbon pool in SOC were significantly improved by 2-9 folds in reclaimed desertification lands. Results revealed that increased biomass production with abundant residue retention is crucial for ameliorating soil quality, stabilizing high yield and economic gains, supporting the "High Biomass Cropping System" ecological hypothesis. Ecological limitations and opportunities to sustainable utilization of sandy desertification land were discussed.
长期的土壤特性和作物生长数据是了解荒漠化土地形成过程的重要资源。从长期观测中得出的有助于维持或提高土壤质量和生产力的一般性生态原则对于指导田间管理实践至关重要，而对于新开垦的荒漠化土地仍然需要进行评估。在这里，一项为期 14 年的实验表明，在灌溉和施肥的荒漠化土地中，土壤质量指数（SQI）呈现出“增加-减少-恢复”的趋势，而在仅灌溉的荒漠化土地中，SQI 则一直处于较低水平。经过 3-4 年的连续灌溉和施肥管理，稳定地获得了较高的产量和净收入。作物生产力与 SQI 之间的相关性遵循饱和特征曲线，阈值为 0.5，对应于土壤有机碳（SOC）~5.0 g kg，低于该阈值，作物生产力呈线性下降。观察到的 SQI 年际变化的 60%可以用叶凋落物的数量来解释，其解释能力是根残体的三倍。开垦的荒漠化土地中，土壤微生物生物量碳、水稳性团聚体和 SOC 中的重碳库显著增加了 2-9 倍，而土壤机械组成部分没有发生实质性变化。结果表明，增加生物量生产和丰富的残体保留对于改善土壤质量、稳定高产和经济收益至关重要，支持了“高生物质种植系统”生态假说。本文还讨论了可持续利用荒漠化土地的生态限制和机遇。
