Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA.
Environ Pollut. 2010 Apr;158(4):1088-94. doi: 10.1016/j.envpol.2009.07.005. Epub 2009 Jul 23.
The potential for storing additional C in U.S. Corn Belt soils - to offset rising atmospheric [CO(2)] - is large. Long-term cultivation has depleted substantial soil organic matter (SOM) stocks that once existed in the region's native ecosystems. In central Illinois, free-air CO(2) enrichment technology was used to investigate the effects of elevated [CO(2)] on SOM pools in a conservation tilled corn-soybean rotation. After 5 and 6 y of CO(2) enrichment, we investigated the distribution of C and N among soil fractions with varying ability to protect SOM from rapid decomposition. None of the isolated C or N pools, or bulk-soil C or N, was affected by CO(2) treatment. However, the site has lost soil C and N, largely from unprotected pools, regardless of CO(2) treatment since the experiment began. These findings suggest management practices have affected soil C and N stocks and dynamics more than the increased inputs from CO(2)-stimulated photosynthesis.
美国玉米带土壤储存额外碳的潜力 - 以抵消不断上升的大气[CO(2)] - 很大。长期的耕作已经耗尽了该地区原生生态系统中曾经存在的大量土壤有机质 (SOM) 储量。在伊利诺伊州中部，使用自由空气 CO(2) 富集技术研究了大气[CO(2)]升高对保护性耕作玉米-大豆轮作中 SOM 库的影响。在 CO(2)富集 5 和 6 年后，我们研究了不同保护 SOM 免受快速分解能力的土壤组分中 C 和 N 的分布。无论 CO(2)处理如何，都没有孤立的 C 或 N 库，或原状土壤 C 或 N 受到影响。然而，自实验开始以来，该地点已经失去了土壤 C 和 N，主要是来自无保护的库，而不管 CO(2)处理如何。这些发现表明，管理实践对土壤 C 和 N 储量和动态的影响大于 CO(2)刺激光合作用带来的增加投入。
