Elevated soil temperature alters nitrogen uptake, allocation and utilization in maize during the late vegetative...

Area of Science:

• Agricultural Science
• Plant Physiology
• Environmental Science

Background:

• Rising global temperatures and soil warming pose risks to maize productivity.
• Understanding soil warming's effects on root function and nitrogen utilization is crucial.

Purpose of the Study:

• To investigate the impact of elevated soil temperatures on maize root morphology, nitrogen uptake, and grain yield.
• To determine the threshold for adverse effects of soil warming on maize nitrogen metabolism.

Main Methods:

• A controlled greenhouse experiment using ¹⁵N-labeled urea to trace nitrogen dynamics.
• Three soil temperature regimes (28°C, 33°C, 38°C) were applied during the late vegetative stage.
• Analysis of root morphology, physiological parameters, nitrogen content, and grain yield.

Main Results:

• Soil warming significantly altered root structure, decreasing root length and surface area while increasing cortical lacunae.
• ¹⁵N uptake rate decreased by 46.97-60.44% with elevated soil temperatures.
• High soil temperatures (38°C) led to accelerated leaf senescence, reduced kernel weight, and a 34.52% decline in grain yield.

Conclusions:

• Soil warming disrupts nitrogen uptake, allocation, and utilization in maize.
• 38°C soil warming exceeds maize's capacity for coordinated nitrogen supply during grain filling.
• Findings provide a physiological basis for developing strategies to mitigate soil warming's negative effects on maize.