Plants actively control nitrogen cycling: uncorking the microbial bottleneck

Area of Science:

• Ecology
• Soil Science
• Plant Biology

Background:

• Ecologists have long investigated the relationship between plant species composition and ecosystem properties.
• It is recognized that biological communities can influence soil properties, not just be shaped by them.
• Recent research suggests soil microorganisms dominate nitrogen cycling, potentially limiting plant species' feedback on soil nitrogen transformations.

Purpose of the Study:

• To review the role of plant species in driving soil nitrogen cycling.
• To challenge the view that microorganisms solely control soil nitrogen transformations.
• To identify mechanisms and characteristics of plant-soil-plant feedback systems.

Main Methods:

• Literature review focusing on plant strategies and their impact on soil nitrogen cycling.
• Analysis of existing research on plant-microorganism interactions in nitrogen cycling.
• Proposal of testable mechanisms for plant-driven nitrogen cycle feedback.

Main Results:

• Plant species significantly influence soil nitrogen cycling rates through distinct nitrogen acquisition strategies.
• Plants can actively control the nitrogen cycle, impacting soil nitrogen availability and their own fitness.
• Litter properties, while influential, do not negate the significant role of plants in nitrogen cycling.

Conclusions:

• Plant species, not just microorganisms, play a major role in regulating soil nitrogen cycling.
• Plant-driven feedback mechanisms (plant-litter-soil-plant) are crucial for ecosystem functioning.
• Understanding plant and ecosystem characteristics is key to predicting the strength of these feedback loops.