夜间增温对冬小麦根系生长和土壤养分有效性的影响

气候变暖存在明显的昼夜不对称性，夜间气温升高幅度显著高于白天.本研究采用夜间被动式增温系统，于2009-2010年在我国冬小麦主产区（石家庄、徐州、许昌和镇江）进行全生育期田间增温试验，研究了土壤pH值、速效养分和抽穗期冬小麦根系对夜间增温的响应.结果表明： 与不增温对照相比，夜间增温显著降低了土壤pH值和速效养分含量，并在一定程度上提高了根系干质量和根冠比.冬小麦整个生育期，夜间增温分别使石家庄、徐州、许昌和镇江试验点土壤pH值平均降低0.4%、0.4%、0.7%和0.9%，碱解氮含量平均降低8.1%、8.1%、7.1%和6.0%，速效磷含量平均降低15.7%、12.1%、19.6%和25.8%；速效钾含量平均降低11.5%、7.6%、7.6%和10.1%.增温处理下，石家庄、徐州和镇江试验点抽穗期冬小麦根系干质量分别平均增加31.5%、27.0%和14.5%；石家庄、许昌和镇江试验点抽穗期冬小麦根冠比分别平均提高23.8%、13.7%和9.7%.夜间增温可能通过改变土壤化学特性影响土壤养分供应和冬小麦生长

Comprehensive evaluation on the evolution characteristics of artificial oasis in Sangong River Basin of Xinjiang,Northwest China

Climate warming has an obvious asymmetry between day and night, with a greater increment of air temperature at nighttime than at daytime. By adopting passive nighttime warming (PNW) system, a two-year field experiment of nighttime warming was conducted in the main production areas of winter wheat in China (Shijiazhuang of Hebei Province, Xuzhou of Jiangsu Province, Xuchang of Henan Province, and Zhenjiang of Jiangsu Province) in 2009 and 2010, with the responses of soil pH and available nutrient contents during the whole growth periods and of wheat root characteristics at heading stage determined. As compared with the control (no nighttime warming), nighttime warming decreased the soil pH and available nutrient contents significantly, and increased the root dry mass and root/shoot ratio to a certain extent. During the whole growth period of winter wheat, nighttime warming decreased the soil pH in Shijiazhuang, Xuzhou, Xuchang, and Zhenjiang averagely by 0.4%, 0.4%, 0.7%, and 0.9%, the soil alkaline nitrogen content averagely by 8.1%, 8.1%, 7.1%, and 6.0%, the soil available phosphorus content averagely by 15.7%, 12.1%, 19.6%, and 25.8%, and the soil available potassium content averagely by 11.5%, 7.6%, 7.6%, and 10.1%, respectively. However, nighttime warming increased the wheat root dry mass at heading stage in Shijiazhuang, Xuzhou, and Zhenjiang averagely by 31.5%, 27.0%, and 14.5%, and the root/shoot ratio at heading stage in Shijiazhuang, Xuchang, and Zhenjiang averagely by 23.8%, 13.7% and 9.7%, respectively. Our results indicated that nighttime warming could affect the soil nutrient supply and winter wheat growth via affecting the soil chemical properties.