Root traits and nitrogen fertilizer recovery efficiency of corn grown in biochar-amended soil under greenhouse conditions

Abstract

Biochar can improve crop yields and nutrient uptake by altering soil properties and root growth. The goals of this study were to determine (1) how biochar alters soil NH4-N availability and corn root development and (2) whether the biochar-induced changes in the plant-soil system coincide with increased nitrogen fertilizer recovery efficiency (FRE) when plants reach the reproductive stage. Corn was grown in two soils amended (or not) with biochar, at five N fertilizer rates (ranging from 0 to 300 kg N ha−1). Soil chemical properties, root and shoot biomass and shoot N uptake were measured at the V3 and R1 stages, roots traits at the V3 stage and FRE at the R1 stage. Biochar increased soil CEC and root growth at the V3 stage. Biochar increased soil available NH4-N, CEC, root growth and root metabolic activity and N uptake at the R1 stage. Fertilizer recovery efficiency was increased in the presence of biochar when N fertilizer was applied at 75 and 150 kg N ha−1. Biochar stimulated early root development, allowing plants to take advantage of increased NH4-N retention concentration in soil by biochar, thereby increasing FRE at the R1 stage at lower N fertilizer application rates.