Plants

Phosphorus (P) is a key nutrient limiting crop growth and productivity, particularly in saline-alkali soils with low P availability. Arbuscular mycorrhizal fungi (AMF) have the potential to enhance P uptake in alfalfa (Medicago sativa L.); however, the synergistic effects and underlying biological mechanisms by which AMF improve P acquisition and utilization efficiency under varying P application levels remain unclear. To explore P acquisition strategies associated with AMF status, root morphology traits, rhizosphere carboxylate exudation, soil properties and microbial biomass, we conducted a pot experiment growing alfalfa in saline-alkali soil under four P application levels (0, 5, 10, and 20 mg kg⁻¹), with or without AMF inoculation. Our results showed that AMF colonization and P application synergistically increased alfalfa biomass and shoot/root P concentrations. Notably, at a low P application level of 5 mg kg⁻¹, the mycorrhizal contribution to P absorption and P-utilization efficiency reached their highest levels, while both declined under high P conditions (20 mg kg⁻¹), suggesting an interaction between P availability and AMF efficacy. Structural equation modeling (SEM) and regression analysis revealed that rhizosphere carboxylate concentrations were positively associated with P-utilization efficiency, whereas soil available P, microbial biomass P (MBP) and carbon (MBC) negatively affected it. Among these factors, AMF-induced enhancement of rhizosphere carboxylate exudation played a critical role in promoting P-utilization efficiency in alfalfa under low-P conditions. In contrast, higher P availability reduced rhizosphere carboxylate concentrations, resulting in lower P-utilization efficiency. In conclusion, the combination of AMF colonization and low P application synergistically improves P acquisition and utilization efficiency in alfalfa, providing valuable insights for sustainable nutrient management in saline-alkali soils with limited P availability.

The world faces increasing food, environmental, and human security issues, primarily attributed to an overburdened agricultural sector struggling to keep pace with rising population and demand for food, energy, and fiber. Advances in food production and agriculture, especially with monoculture farming, have continued to meet these demands but at a high price regarding resource depletion and environmental devastation. This is especially severe in developing world areas with rural populations with thin resource margins. Regenerative agriculture has emerged as a solution to provide shielding for food production, ensure environmental protection, and promote social equity while addressing many of these issues. Regenerative agriculture food production aims to restore soils, forests, waterways, and the atmosphere and operate with lower offsite negative environmental and social impacts. This review discusses the fundamental principles and practices of sustainable plant protection for regenerative farming. It focuses on the role of biological and ecological processes, reduces non-renewable inputs, and aims to incorporate traditional ecological knowledge into pest control practices. It offers essential transition strategies, including critical changes from conventional integrated pest management (IPM) to agro-ecological crop protection, focusing on systemic approaches to design agroecosystems. It also reaffirms the importance of a vast diversity of pest control methods that are culturally, mechanistically, physically, and biologically appropriate for regenerative farming practices. Ultimately, the aim is to encourage ecological, economic, and social sustainability for the future of more resilient and controlled agricultural practices.

The global population growth has driven the widespread adoption of genetically modified crops, with Bt maize, due to its insect resistance, becoming the second most widely planted GM crop. However, studies on the effects of continuous Bt maize cultivation on soil ecosystems are limited, and there is an urgent need to assess its ecological safety at the regional scale. To evaluate the potential effects of continuous cultivation of transgenic Bt maize on the soil ecosystem, a five-season continuous planting experiment was conducted using two Bt maize varieties (5422Bt1 and 5422CBCL) and their near-isogenic conventional maize (5422). After five consecutive planting seasons, bulk soil and rhizosphere soil were collected. The main nutrient contents of the bulk soil were measured, and high-throughput sequencing was employed to analyze microbial diversity and community composition in both soil types. The results showed that, compared with the near-isogenic conventional maize 5422, continuous planting of Bt maize varieties 5422Bt1 and 5422CBCL did not affect the contents of organic matter, total nitrogen, total phosphorus, total potassium, alkaline hydrolyzable nitrogen, available phosphorus, or available potassium in bulk soil. Regarding the microbial communities in bulk soil, there were no significant differences in the α-diversity indices of bacteria and fungi after five consecutive seasons of Bt maize cultivation, compared with soils planted with the near-isogenic conventional maize 5422. Proteobacteria and Ascomycota were the dominant phyla of bacteria and fungi, respectively. Principal coordinate analysis (PCoA) and redundancy analysis (RDA) revealed that the structure of microbial communities in bulk soil was primarily influenced by factors such as OM, TP, TN and AN, whereas the Bt maize varieties had no significant effect on the overall community structure. Regarding the rhizosphere soil microbial communities, compared with the near-isogenic conventional maize 5422, the evenness of the bacterial community in the rhizosphere soil of Bt maize decreased, leading to a reduction in overall diversity, whereas species richness showed no significant change. This change in diversity patterns further contributed to the restructuring of the rhizosphere soil microbial community. In contrast, the fungal community showed no significant differences among treatments, and its community structure remained relatively stable. Proteobacteria and Ascomycota were the dominant phyla of bacteria and fungi, respectively. Principal coordinate analysis (PCoA) indicated that continuous cultivation of Bt maize for five seasons had no significant effect on the structure of either bacterial or fungal communities in the rhizosphere soil. In summary, continuous cultivation of Bt maize did not lead to significant changes in soil nutrient contents or microbial community structures, providing a data foundation and theoretical basis for the scientific evaluation of the environmental safety of transgenic maize in agricultural ecosystems.