61 / 2021-06-30 11:10:30

Biochar enhanced carbon sequestration and plant growth in coastal wetland soils in the Yellow River Delta, China

soil degradation; food security; rhizosphere; nutrient availability; salinity

Exacerbating degradation of coastal soil weakens the sustainability of coastal primary productivity, thus threatens cultivated land supply and food security within the region. It is urgent to restore these degraded soils to ensure sustainable soil management and food production using eco-friendly technologies. Biochar with multiple benefits provides such an opportunity. Therefore, a 52-day pot experiment was conducted to explore the effects of individual or co-application of peanut shell derived biochar and inorganic fertilizer on growth of two halophytes, Sesbania (Sesbania cannabina) and Seashore mallow (Kosteletzkya virginica) in a coastal soil collected from the Yellow River Delta, as well as nutrient availability and rhizosphere microbial modulation. The results showed that biochar addition alone increased the seed germination rate of Sesbania and Seashore mallow by 275–395% and 44.4–48.4% compared to the control treatment, respectively, but the co-application had non-significant effect. The biochar alone and co-application significantly increased the total biomass for Sesbania and Seashore by 111–152%, 118–156%, 32.8–76.7%, and 44.9–66.2% relative to the control treatment, respectively. The enhanced growth of the halophyte plants induced by the biochar addition was mainly ascribed to two aspects. On the one hand, biochar addition significantly increased soil organic matter content, N and P availability. On the other hand, the biochar increased the bacterial activity and abundance associated with N and P transformations in the rhizosphere such as Pseudomonas and Bacillus. These observations showed that biochar alone or co-applied with fertilizer enhanced coastal primary productivity and thus could be a promising option for restoring the degraded coastal soil.