Seasonal changes in soil properties caused by slash and burn agriculture practice in a humid temperate region of northeast Japan

Abstract

We investigated the influence of slash and burn (SBA) practice on selected soil properties and its influence on the dynamics of mineral nutrients in a typical humid temperate climate region of northeast Japan. Soils were sampled from an SBA site and compared to an adjacent original forest site (control) located in Shonai area, Yamagata Prefecture, from August 2018 to August 2019 with monthly intervals for SBA and bi-monthly intervals for control, except the snow cover period. The results showed that SBA could not evidently affect soil pH, electric conductivity, available phosphorus, exchangeable cations (Ca2+, Mg2+ and K+), and effective cation exchange capacity. This was likely due to the low severity of fire in the SBA site. On the other hand, cultivation of turnip affected seasonal changes of soil NH4+ and NO3− mainly attributed to crop absorption. Soil MBC and MBN were significantly increased after one month of burning due to available soil nutrients from plant biomass burning which stimulated microbial growth. There were no significant changes in SOC and TN between the clear-cut stage (before SBA), and after one year at the end of the study period. This was largely due to the short turnip cultivation period and the quick covering by succession plants. In conclusion, our results showed the SBA practice affected soil properties in this study was not relatively significant.