Beneficial Effects of Biochar-Based Organic Fertilizer on Nitrogen Assimilation, Antioxidant Capacities, and Photosynthesis of Sugar Beet (<i>Beta vulgaris</i> L.) under Saline-Alkaline Stress

• Main Authors: Pengfei Zhang, Fangfang Yang, He Zhang, Lei Liu, Xinyu Liu, Jingting Chen, Xin Wang, Yubo Wang, Caifeng Li
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Agronomy
• Subjects: sugar beet; saline-alkaline stress; biochar-based organic fertilizer; nitrogen assimilation; antioxidant enzymes; root activity
• Online Access: https://www.mdpi.com/2073-4395/10/10/1562

The Songnen Plain, whose climatic conditions are perfectly suited to sugar beet growth, is located in northeastern China. Unfortunately, this region has a lot of saline-alkaline land, which is the most important factor limiting sugar beet production. This study was undertaken to determine whether biochar-based organic fertilizer could alleviate the negative effect of saline-alkaline soil on sugar beet yield and whether such an effect correlated with changes in nitrogen assimilation, antioxidant system, root activity, and photosynthesis. Three treatments were established: Chemical fertilizers were applied to neutral soil (CK), chemical fertilizers were applied to saline-alkaline soil (SA), and biochar-based organic fertilizer was applied to saline-alkaline soil (SA + B). Our results showed that saline-alkaline stress significantly inhibited the nitrogen assimilation and antioxidant enzymes activities in root, root activity, and photosynthesis, thus significantly reducing the yield and sugar content of sugar beet. Under saline-alkaline conditions, the application of biochar-based organic fertilizer improved the activities of nitrogen assimilation enzymes in the root; at the same time, the antioxidant enzymes activities of the root were significantly increased for improving root activity in this treatment. Moreover, the application of biochar-based organic fertilizer could improve the synthesis of photosynthetic pigments, PSII (Photosystem II) activity, stomatal opening, and photosynthesis of sugar beet under saline-alkaline conditions. Hence, the growth and yield of sugar beet were improved by applying biochar-based organic fertilizer to saline-alkaline soil. These results proved the significance of biochar-based organic fertilizer in alleviating the negative effect of saline-alkaline stress on sugar beet. The results obtained in the pot experiment may not be viable in field conditions. Therefore, in the future, we will verify whether biochar-based organic fertilizer could alleviate the adverse effects of saline-alkaline stress on sugar beets yield under field conditions.