【农田温室气体重要产生途径低估】Xia Zhu Martin Burger Timothy A. Doane and William R. Horwath. Ammonia oxidation pathways and nitrifier denitrification are significant sources of N2O and NO under low oxygen availability. PNAS
农 田作为温室气体排放的主要来源之一，其排放途径越来越引起各国科学家的高度关注。中科院 成都生物所吴宁研究组朱霞博士与其合作者通过对土壤氧化亚氮和一氧化氮产生途径的研究，揭示了在低氧条件下土壤中温室气体氧化亚氮产生的主要过程途径。该 成果于4月2日在线发表于美国《国家科学院院刊》。
土壤氧化亚氮产生途径主要有氨氧化过程与反硝化细菌反硝化过程。人们普遍认为，在土壤高水分条件下，反硝化细菌反硝化过程作为氧化亚氮的主要产生途径是因为：在高水分条件下土壤氧气不足，从而致使氧化亚氮通过反硝化细菌反硝化过程产生。
朱霞博士通过控制土壤中氧气浓度和使用同位素标记法，对不同氧气条件下土壤氧化亚氮和一氧化氮产生途径进行了深入研究。最终发现，在低氧条件下，土壤氧化亚氮与一氧化氮产生的主要途径为氨氧化过程，而非反硝化细菌反硝化过程。
这一研究结论为人们对土壤氧化亚氮和一氧化氮产生来源提供了新认识。该研究结果得到了美国加州大学戴维斯分校土壤科学J.G. Boswell首席科学家基金的支持。（来源：中国科学报 彭丽 何奕忻）
【施氮、磷肥条件下草地土壤养分和其它主要属性】Aimé Jean Messiga Noura Ziadi Gilles Bélanger and Christian Morel. Soil Nutrients and Other Major Properties in Grassland Fertilized with Nitrogen and Phosphorus. SSSAJ 2013 Vol. 77 No. 2 p. 643-652
Abstract
Understanding how nutrient distribution relates to soil depth is essential for improving fertilization practices for grasslands. This study evaluated the distribution of P other elements and selected soil properties at 0- to 5-cm and 5- to 15-cm layers in a grass sward following several years of N and P fertilization. Soil samples were collected in the spring of 2010 from a timothy grass sward (Phleum pratense L.) established in 1998 on a gravely-sandy loam soil. Sixteen combinations of P (0 15 30 and 45 kg ha−1) as triple superphosphate and N (0 60 120 and 180 kg ha−1) as calcic ammonium nitrate were broadcast annually from 1999 to 2006 in a split-plot design with P as main plots and N as subplots. Concentration of three soil P indicators [water (CP) Mehlich-3 (PM3) and acid oxalate (POx) extractable P] and total phosphorus (PT) were greater in the 0- to 5-cm than in the 5- to 15-cm layer. Differences in con
附件：