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Nitrogen and phosphorus are essential nutrients for plant growth, but their excessive use in agriculture can harm the environment through nutrient runoff and greenhouse gas emissions. While high doses of soluble fertilizers enhance crop yields in the short term, they compromise environmental quality and agroecosystem resilience. Researcher Jean-Thomas Cornelis at the University of British Columbia, in collaboration with the BC Blueberry Council, the BC Hazelnut Growers Associations and BC Grain Producers Association, are investigating how plants grow under nutrient reduced conditions, and the impact fertilizer has on nutrient acquisition and carbon sequestration at the tip of plant roots. 

This study reviewed 36 published works across 30 crop and soil systems to explore more sustainable nutrient management strategies. Findings showed that reducing phosphorus fertilizer by up to 50% increased root exudation by 30%, with only a minimal (2%) decrease in plant growth. Conversely, cutting nitrogen resulted in a smaller rise in exudation (7%) but a significant 20% reduction in growth. These results suggest that moderate phosphorus limitation can promote more active root systems and enhance nutrient acquisition and soil carbon capture.

In-field soil trails with white lupin, reducing phosphorus from 40 to 15 mg P kg?¹ soil did not significantly impact microbial biomass in bulk soil but slightly decreased microbial biomass carbon (4–18%) in rhizosphere soils. Plant responses and exudate profiles varied depending on soil type, underlining the importance of soil characteristics in optimizing plant-soil interactions. The study also examined water stress in hazelnut saplings, finding that drought increased root exudation and belowground carbon investment. This response indicates that plants adjust resource allocation under stress, a trait that could be leveraged to improve agroecosystem resilience. This exploratory research provides insight into plants’ adaptive strategies in water stress and nutrient limitation that could support sustainable agricultural systems in a changing climate.