Abstract:

【Objective】Earlier techniques made the measurement and analysis of soil temperature uncertain. Tillage effects on soil temperature are insufficiency at previously studies. An experiment was conducted to characterize the tillage effects of diurnal dynamic of soil temperature and its response to air temperature in winter wheat field, North China Plain. 【Method】 Conventional tillage (CT), rotary tillage (RT) and no tillage with stubble covered (NT) were treated from 2004 to 2005 at Luancheng Station of Hebei Province. Temperature was measured continuously by thermo-time domain reflectometry. 【Result】 Results showed that the diurnal dynamic of each layer soil was a sine wave; the diurnal temperature fluctuation was a taper and soil temperature was delayed by 1.2 h per 5 cm increment of soil depth from 2.5-80 cm; diurnal highest and lowest soil temperature was significantly affected by different tillage systems with one of the reason was residue covering ratio; diurnal highest soil temperature at 2.5 cm layer was decreased by 0.66-4.85℃ under NT at active stages of winter wheat, but it was increased by 0.64-0.87℃ at overwintering stage; diurnal soil temperature fluctuation range at the 2.5 cm layer was decreased significantly by 0.65-5.21℃ and 0.48-3.89℃ at early stages (emergence -jointing) of winter wheat under NT, compared with CT and RT, respectively. 【Conclusion】 Soil temperature responses to air temperature significantly under different tillage systems. The main characteristic of tillage effects on soil temperature is that the extentence of soil temperature fluctuation is changed significantly at early stages of winter wheat. More decrease in high temperature and less increase in low temperature are the reasons that NT shows a lower temperature effect at active stages. NT with higher temperature at each time of day results in higher temperature effect at hibernation of winter wheat.

Key words: tillage')">tillage, soil temperature, air temperature