Effects of Biochar and Soil Organic Matter Levels on Physicochemical Properties of Mollisol and Soybean's Biomass

摘要

<正>Long term tillage in mollisol of Northeast China has led to an inhomogeneous distribution of soil organic matter content.Biochar, a carbon material, changes the soil carbon pool and physical-chemical characteristics after adding to the soil. However,themechanismremainsunclearfortherelationbetweenthesoilorganicmatterlevelandbiocharamount.So,thesoilphysical and chemical properties and soybean growth in a two-year pot experiment were detected at three levels of soil organic matter and three biochar additions (0, 1%and 10%). The difference was found in two biochar application rates. The 1%biochar addition had no positive effect on the soil chemical properties based the two-year experiment. However, 10%biochar application significantly increased the soil water content (8.0%–39.7%), the total porosity (9.7%–21.3%), pH (0.26–0.84 unit), organic matter content (89.0%–261.2%), and the available potassium content (29.0%–109.1%). The biomass of soybean increased by 19.4%–78.1%after biochar addition, yet, the soil bulk density reduced at the range of 12.6%–26.0%by 10%biochar addition. Only the 100-grain weight was correlated to the interaction of biochar and the native soil organic matter. All the indicators showed that the interaction between biochar and soil organic matter level was weak in mollisol. The effects of biochar on the physical-chemical properties relied on its amount.When biochar is applied to the soil, the amount of biochar should be considered rather than the native soil organic matter level.

关键词

biochar / soil organic matter / bulk density / available nutrient