High N availability decreases N uptake and yield under limited water availability in maize

Area of Science:

• Agricultural Science
• Soil Science
• Plant Physiology

Background:

• Water and nitrogen (N) are critical limiting factors for global plant productivity.
• Understanding the interplay between water availability and N dynamics in agricultural systems is crucial but lacking.
• Plant N requirements are uncertain under water limitation due to interactive effects on growth, demand, and uptake.

Purpose of the Study:

• To investigate the impacts of N application and water availability on plant growth and N movement.
• To analyze water productivity, N productivity, N uptake, N recovery, and greenhouse gas emissions.
• To understand plant foraging and resource availability processes under varying water and N conditions.

Main Methods:

• Field experiment in a semi-arid system (northeastern Colorado, USA).
• Manipulated soil N availability and water availability.
• Measured above and belowground plant growth, water and N productivity, N uptake, N recovery, and soil nitrate levels.

Main Results:

• Moderately high soil N depressed grain yield and shoot growth under both water conditions.
• Low N availability led to enhanced N recovery in aboveground tissues.
• Limited water availability reduced N uptake and increased deep soil nitrate accumulation by 30%.

Conclusions:

• Plant N needs are not linearly related to water use.
• Integrated understanding of water-N interactions, plant foraging, and N availability processes is essential.
• Current N management strategies may need adjustment based on water availability to optimize productivity and minimize N losses.