Nitrogen (N) serves as an essential nutrient for yield formation across diverse crop types. However, agricultural production encounters numerous challenges, notably high N fertilizer rates coupled with low N use efficiency and serious environmental pollution. Deep placement of nitrogen fertilizer (DPNF) is an agronomic measure that shows promise in addressing these issues. This review aims to offer a comprehensive understanding of DPNF, beginning with a succinct overview of its development and methodologies for implementation. Subsequently, the optimal fertilization depth and influencing factors for different crops are analyzed and discussed. Additionally, it investigates the regulation and mechanism underlying the DPNF on crop development, yield, N use efficiency and greenhouse gas emissions. Finally, the review delineates the limitations and challenges of this technology and provides suggestions for its improvement and application. This review provides valuable insight and reference for the promotion and adoption of DPNF in agricultural practice.

Over the last few decades, waterlogging stress has increasingly threatened global cotton production. Waterlogging results in reduced soil oxygen, impairing the growth and development of this valuable crop and often resulting in severe yield loss or crop failure. However, as cotton has an indeterminate growth habit, it is able to adapt to waterlogging stress by activating three mechanisms: the escape, quiescence, and self-regulating compensation mechanisms. The escape mechanism includes accelerated growth, formation of adventitious roots, and production of aerenchyma. The quiescence mechanism involves reduced biomass accumulation and energy dissipation via physiological, biochemical, and molecular events. The self-regulation compensation mechanism allows plants to exploit their indeterminate growth habit and compensatory growth ability by accelerating growth and development following relief from waterlogging stress. We review how the growth and development of cotton is impaired by waterlogging, focusing on the three strategies associated with tolerance and adaptation to the stress. We discuss agronomic measures and prospects for mitigating the adverse effects of waterlogging stress.