Agronomy (May 2018)
The Effects of Rice Straw and Biochar Applications on the Microbial Community in a Soil with a History of Continuous Tomato Planting History
Abstract
Soil microbial abundance and diversity change constantly in continuous cropping systems, resulting in the prevalence of soil-borne pathogens and a decline in crop yield in solar greenhouses. To investigate the effects of rice straw and biochar on soil microbial abundance and diversity in soils with a history of continuous planting, three treatments were examined: mixed rice straw and biochar addition (RC), rice straw addition (R), and biochar addition (C). The amount of C added in each treatment group was 3.78 g kg−1 soil. Soil without rice straw and biochar addition was treated as a control (CK). Results showed that RC treatment significantly increased soil pH, available nitrogen (AN), available phosphorus (AP), and potassium (AK) by 40.3%, 157.2%, and 24.2%, respectively, as compared to the CK soil. The amount of soil labile organic carbon (LOC), including readily oxidizable organic carbon (ROC), dissolved organic carbon (DOC), and light fraction organic carbon (LFOC), was significantly greater in the RC, R, and C treatment groups as compared to CK soil. LOC levels with RC treatment were higher than with the other treatments. Both rice straw and biochar addition significantly increased bacterial and total microbial abundance, whereas rice straw but not biochar addition improved soil microbial carbon metabolism and diversity. Thus, the significant effects of rice straw and biochar on soil microbial carbon metabolism and diversity were attributed to the quantity of DOC in the treatments. Therefore, our results indicated that soil microbial diversity is directly associated with DOC. Based on the results of this study, mixed rice straw and biochar addition, rather than their application individually, might be key to restoring degraded soil.
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