Abstract:
Here, to investigate the effects of banana stem and its biochar application on soil fertility in the Pearl River Delta, the effects of applying 0.5%, 1.0%, and 2.0% banana stem, rice straw, and their biochar on the composition of soil water-stable aggregates were evaluated in soil culture and pot experiments. The mean weight diameter (MWD), geometric mean diameter (GMD), fractal dimension (
D), and mean weight specific surface area (MWSSA) were used to evaluate soil aggregate stability. The results revealed the following:1) Water-stable aggregates in the studied soil was dominated by < 0.25-mm micro-aggregates, followed by 1-0.5-mm aggregates, accounting for 29.80%-47.55% and 18.19%-20.08% of the aggregates, respectively. 2) Applying 1.0% and 2.0% banana stem and 2% rice straw significantly increased >0.25 mm macro-aggregate content and soil aggregate stability. Compared with the control treatment, the soil aggregate MWD increased by 45.60%, 62.37%, and 65.50%, respectively; GMD increased by 43.45%, 55.34%, and 60.66% respectively;
D decreased by 2.23%, 2.32%, and 2.78% respectively; and MWSSA decreased by 18.14%, 20.09%, and 23.01% respectively. 3) The MWD and GMD significantly positively correlated with >5 mm, 5-2 mm, and 2-1 mm soil aggregate percentages, and significantly negatively correlated with < 0.25-mm soil micro-aggregate percentage. The
D value and MWSSA significantly positively correlated with < 0.25-mm soil micro-aggregate percentage, and significantly negatively correlated with >5 mm, 5-2 mm, and 2-1 mm soil aggregate percentages. 4) The results of principal component analysis and difference significance test indicated that applying 2.0% and 1.0% banana stem had a better effect in improving soil aggregate stability, and this effect was not significantly different from that of 2.0% rice straw application; however, the application of biochar did not increase the stability of aggregates in the short term. This study provides a reference for effectively utilizing banana stem waste and improving soil fertility.