As the world’s population grows, pursuing sustainable agricultural production techniques to increase crop yields is critical to ensuring global food security. The development and application of biological agents is of great significance in promoting the sustainable development of agriculture. This study aimed to investigate the role of JZ (compound microbial agent) and MZ (biological agent made from plant materials) in improving the rhizosphere microecological environment and nutrient availability for rice. This study found that JZ enriched Cyanobacteria with biological nitrogen fixation functions; spraying MZ can enrich some beneficial microbiota, such as Bradyrhizobium, playing a role in symbiotic nitrogen fixation. Meanwhile, JZ and MZ were found to affect rhizosphere soil metabolism and improve potassium and nitrogen availability. JZ may promote the degradation of fungicides in the rhizosphere soil environment. Overall, applying biological agents through optimizing rice growing environment to improve yield showed great potential.

Against the backdrop of global population and food demand growth, the development of ratoon rice is conducive to increasing food production and ensuring food security. Applying agricultural biotechnology and plant growth regulator to ratoon rice production is a key measure to promote the development of green agriculture and address the challenges of global food security. A total of 4 treatments were set up in this study: T1 (regulator); T2 (biological agent made from plant materials); T3 (microbial agent); and control (CK). The results showed that T3 up-regulated many key genes (OsHsfC1b, OsCNGC16, OsOSM1, OsSAPK9, and DTH2, etc.) and metabolites (spermine, citric acid, riboflavin, and shikimic acid). T2 was found to up-regulate key genes OsAPT2, OsZIP8, OsCIPK14, OsCIPK7, OsPR4c, and OsVIT2, and its regulatory effects involved carbohydrate, lipid, and amino acid metabolism, etc. In addition, the two biological agents and one regulator significantly increased the accumulation of stem dry matter and yield in the first season. T1, T2, and T3 significantly increased the final regenerative capacity of Yongyou4949 at D5 (fifth node from the top); T1 and T2 significantly increased the maximum and final regenerative capacities of Shuangliangyou138 at D5. This study provided guidance for developing more effective agricultural management strategies, which is conducive to the sustainable development of agriculture.

Against the backdrop of a changing global climate, the soil environment may undergo significant changes, directly affecting agricultural productivity and exacerbating global food security issues. Three different substrates were set up in this study, namely, S (high sand and low nutrient content), T (medium sand and medium nutrient content), and TT (low sand and high nutrient content). The results showed that the root/shoot ratio increased as the sand content increased (nutrient content decreased). Rice in different substrates had various degrees of dependence on antioxidant enzymes and antioxidants. For example, seedlings in TT treatment may depend more on ascorbic acid (AsA) compared to T. In addition, compared with S and T, the photosynthetic activity of rice in the optimized substrate (TT) was the highest; the net photosynthetic rate (Pn) of TT seedlings was significantly higher than that of T. This study also detected that the change in substrates affected the gas exchange parameters of rice leaves. The transpiration rate (Tr) and stomatal conductance (Gs) of the TT treatment were higher than those of the T treatment. The results of this study may provide a scientific basis for formulating agricultural management strategies.

Studying the salt tolerance mechanisms of rice under a single substrate has certain limitations. The salt tolerance strategies of rice may differ under dif