Terrestrial plants require nutrients in similar proportions

Area of Science:

• Plant physiology
• Ecology
• Biogeochemistry

Background:

• Terrestrial plant nutrient ratios are theoretically similar to the Redfield ratio in marine phytoplankton.
• Plants supplied with abundant nutrients show similar concentration ratios, but uptake may exceed growth requirements.
• Previous studies indicate nutrient ratios vary with nutrient availability.

Purpose of the Study:

• To investigate nutrient concentration ratios in terrestrial plants under varying nutrient supply rates.
• To define optimum nutrient ratios based on the law of the minimum.
• To compare experimentally determined ratios with those derived from literature data.

Main Methods:

• Laboratory experiments with seedlings of diverse plant species under controlled nutrient supply.
• Nutrient supply rates were manipulated to prevent excessive uptake.
• Literature review and calculation of nutrient ratios (N, P, K, Ca, Mg) from published data.

Main Results:

• Similar nutrient concentration ratios were observed among different plant species when nutrients were supplied at non-excessive rates.
• These ratios differed from those found under conditions of free nutrient access.
• Calculated nutrient ratios from literature data closely matched experimental findings.

Conclusions:

• Optimum nutrient ratios are best represented by those found when all nutrients simultaneously limit plant growth.
• The study supports the concept of consistent nutrient ratios across terrestrial plant species under limiting conditions.
• Findings align with theoretical expectations and provide a basis for understanding plant nutrient dynamics in ecosystems.