Labile (active) carbon derives primarily from recent organic matter inputs. It includes carbon from microbial biomass, particulate organic matter, and soil carbohydrates. It is highly sensitive to changes in crop management and is the major source of food (energy) for soil microorganisms. The labile carbon content of soil is considered an excellent indicator of its fertility. Organic soil amendments such as green manures, chicken manure pellets (Acti-Sol type), and slurries—with their lower biological stability index values—provide soils with higher amounts of labile carbon. In comparative trials performed earlier, striking results were obtained with green manures. Although the nutrient content of amendments are sometimes estimated to be on the low side, when actual intakes are measured they trend much higher than the initial estimates. This result could be explained by the significant labile carbon contribution to soil obtained with green manure, which, in turn, stimulates microbial life and, eventually, mineralization. Other studies also point to the role of labile carbon in making phosphorus available. Labile carbon appears to utilize the same binding sites in soil as phosphorus. A labile carbon input would displace some phosphorus into the soil solution, thus making it available again for assimilation into growing plants.
From 2019 to 2020
Market gardening, Fruit production, Field crops
Fertilizer management, Soil health
The determination of a carbon status profile for Saguenay–Lac-Saint-Jean soils could be replicated across Québec.
Groupe multiconseil agricole Saguenay–Lac-Saint-Jean
Research report • Christine LandryBouchard, A., C. Landry. 2020. État de la situation du ratio carbone labile / carbone organique total des sols de la région du Saguenay-Lac-St-Jean. Groupe multiconseil agricole Saguenay–Lac-Saint-Jean. 14 p. Bouchard, A., C. Landry. 2020. État de la situation du ratio carbone labile / carbone organique total des sols de la région du Saguenay-Lac-St-Jean. Groupe multiconseil agricole Saguenay–Lac-Saint-Jean. 14 p. Download Download
Project to quantify the long-term (60+ years) severity of erosion of organic horticultural soils.
The purpose of the project was to develop techniques and tools for maintaining paper mulch during crop growth.
Researcher: Carl Boivin
This project seeks to create farmer partnerships in which participants work on implementing a three-year forage crop rotation protocol in potato and field crop fields.
Researcher: Richard Hogue