Microbial response to physical fertility improvement induced by biochar application to coastal saline-alkali soil, Eastern China

Abstract

Coastal soil has an excellent potential as a land reserve. However, low physical fertility with poor structure might hamper its efficient utilization. A field study was conducted to explore the microbial response to physical fertility improvement induced by biochar addition to a coastal soil. Rice straw biochar (RSB), corn straw biochar (CSB) and cow manure biochar (CMB) with two levels (1% and 3% by weight) were applied to the coastal soil. The results showed that adding biochar significantly improved the coastal soil’s physical fertility, including bulk density, porosity, aggregates stability and water condition. The three kinds of biochar application significantly modified mechanical strength properties, reducing the tensile strength and coefficient of linear extension (COLE), especially with the high dosage application, in comparison with the control treatment. The coastal soil with RSB3% treatment had the highest Shannon index, while CMB3% treatment had the lowest Simpson index. The results showed that porosity, aggregate stability, water and tensile strength were the main physical properties affecting the Shannon index in the coastal soil. Biochar application, especially RSB3% and CMB3%, improved physical properties, microbial diversity and community structure, respectively, thereby contributing to the efficient use of the coastal soil.