Differences of the changes in soil temperature of cold and mid-temperate zones, Northeast China.

Rapid changes in soil temperature are unequivocal under global change, especially in mid-high latitudes. Studies on the relationships between soil temperature and climate system are lacking at regional climatic scale. Here, changes in shallow soil temperature (0, 5, 10, 15, 20 cm), both in the cold temperate zone (CTZ) and the mid-temperate zone (MTZ) in Northeast China, were compared and analyzed using daily data from growing seasons (May to September) from 1964 to 2011. The influences of air temperature and precipitation on soil temperature were analyzed. The results showed that for nearly half a century, the increasing trend of surface soil temperature in the CTZ was lower than that in the MTZ, with + 0.17 and + 0.54 °C/decade, respectively. Air temperature increased faster for the MTZ than the CTZ. Precipitation increased in the CTZ but decreased in the MTZ. Since 1996, the temperature increase and precipitation decrease were more obvious in the MTZ. In summary, given the complex effects of temperature and precipitation, the response of soil temperature was more significant in the MTZ than in the CTZ. These results emphasize the importance of independently researching soil temperature of different climate zones. Susceptibility of soil temperature to global warming will advance our understanding on utilization of climatic resources in the development of agricultural production. [ABSTRACT FROM AUTHOR]