Biochar applied to consolidated land increased the quality of an acid surface soil and tobacco crop in Southern China

Abstract

Soil needs to be ameliorated after land consolidation because this process might decrease soil fertility, soil physical properties, and the growth of microbes, and the application of biochar is one of the soil amelioration methods. However, up to date, no relevant study has been conducted by any field experiment. The objective of this study was to investigate the biochar effect on soil improvement and crop quality. A field experiment with 5 corn stover biochar application rates (0, 1, 5, 10, 20 Mg ha−1) was conducted in an acid soil (Kandiudult soil in US taxonomy) with flue-cured tobacco as representative crop. The results showed that in comparison with 0 Mg ha−1 biochar treatment, the application of biochar decreased the soil bulk density by 13.22%, increased the > 2-mm water-stable soil aggregates by 27.38%, and the 0.25 to 2.00-mm soil aggregates by 45.57% at most. The soil pH, organic carbon, labile organic carbon, and exchangeable Ca and Mg contents increased with increasing biochar application rate. The application of biochar was also beneficial for soil microbial activities. For example, the abundance of actinomyces increased with the biochar application rate, and the maximum increase of 342.28% was recorded at the biochar application rate of 20 Mg ha−1. The application of biochar decreased the total sugar and reducing sugar contents and increased the leaf K content, thus greatly improving the leaf quality of flue-cured tobacco. Biochar applied to consolidated acid soil can play a positive role in flue-cured tobacco production and soil amelioration with regard to soil physical properties and soil nutrient supply capacity. On consolidated land, this is the first study about the effect of biochar application on quality of acid soil and crop, which strengthens the understanding about the role of biochar in soil improvement on consolidated land.