Effects of Biochar Application on the Dynamic of Soil Moisture-Temperature-Salt in Degraded Mollisols During Freezing Period

Abstract

[Objective] Biochar application can change soil physicochemical properties. The study of the effects of different biochar application methods on soil moisture, temperature and electrical conductivity (EC) distribution, which can provide basis for the scientific management of seasonally frozen soil. [Methods] The effects of different biochar application methods on soil liquid water content, temperature and EC during freezing period were studied by field experiment and long-term observation in black soil region of northeast. Biochar application methods included one-time biochar mixed application of 40 t/hm2(HO), biochar bottom application of 40 t/hm2(HE), and the blank was 0 t/hm2(CK). [Results] Both biochar application methods increased the mean soil liquid water content during the freezing period (p HE > CK. The application of biochar application significantly increased soil EC throughout the experimental cycle, and the average soil EC increased by 17.73% and 6.89% in the HO and HE treatments, respectively, compared to CK. The two biochar application methods had different effects on the soil temperature. Compared with CK, the mean soil temperature increased by 0.32 ℃ in the HE treatment, while the mean soil temperature decreased by 0.46 ℃ in the HO treatment. In addition, the HE treatment weakened the range of change in soil liquid water, temperature and EC during the freezing period compared to HO and CK treatments. [Conclusion] Both heterogeneous and homogeneous biochar application were beneficial to increase the liquid water content and EC of degraded black soil during freezing period. Especially heterogeneous biochar application was also beneficial to increase the soil temperature of the tillage layer during freezing period, homogeneous biochar application can also reduce the soil freezing during freezing effect during the same period. Both of the two biochar application modes may have an important impact on the soil moisture-salt transport and material transformation process during the freezing period, and even have an important effect on the spring emergence and early growth of crops.

Keywords

• biochar
• freezing period
• degraded black soil
• soil liquid water content
• soil temperature
• ec