Chromium from Hydrolyzed Leather Affects Soybean Growth and Nodulation

Hydrolyzed leather, obtained from industrial leather waste, is an organic nitrogenous fertilizer with a high chromium (Cr) content. Soybean crops can be adversely affected by the presence of residual Cr in soil after application of hydrolyzed leather fertilizer. The aim of this work was to assess the effect of hydrolyzed leather on Cr absorption, root development, and symbiotic nodulation of soybean plants grown on three different soils including two Lixisols and a Gleysol. These soils were previously fertilized with hydrolyzed leather at three different rates (0.0, 0.1, and 0.8 kg m−2). Soybean shoot height, root development, nodulation, and mineral nutrient concentrations in plant tissues were determined after 45 d of crop growth. The application of hydrolyzed leather significantly increased Cr content in soil and Cr uptake by plants. Surprisingly, Cr was stored mainly in the aerial part of the plants. The presence of Cr had an adverse impact on shoot dry matter (41% reduction) and number of nodules (49% reduction) per plant grown on the soil with the lowest cation exchange capacity. However, no other significant effect was observed in nodule weight, diameter, or any other measured parameters.