Biological inhibition of denitrification (BDI) in the field: Effect on plant growth in two different soils

Abstract Intensive agriculture uses increasingly large amounts of nitrogen fertilizers to increase yields because nitrogen is one of the limiting factor of plant growth. Plants are in direct competition with denitrifying bacteria for nitrate, but biological denitrification inhibition (BDI) is a strategy developed by some plants in which procyanidins are produced that inhibit denitrification. This phenomenon increases the available nitrate in the soil. Previous results showed that the addition of procyanidins to lettuce fields allowed effective BDI and increased soil nitrate and plant growth. However, agriculture is performed in different soils, and the action of procyanidins could depend on the type of soil. In this study, we tested the effect of procyanidin amendment on lettuce growth in two types of soils: loamy sand and sandy clay loam. Our results show that in both soils, the addition of procyanidins causes inhibition of denitrification, an increase in available nitrate, counter-selection of denitrification communities and a gain in plant mass without modification of the soil structure. This study highlights a sustainable agricultural method effective in a variety of soils.