The Potential Agricultural Use of High Carbon Char As Soil Amendment: A Laboratory Study.

Char, a local industrial by-product at Scottsbluff, NE contains around 30% total carbon (C) in addition to many essential plant nutrients. It can be a potential source of soil amendment to enhance soil nitrogen (N) retention and thereby, minimize environmental N losses. However, there is scarcity of data on dynamics of N in soil following application of char. A laboratory incubation study will be conducted in summer 2017 at UNL Panhandle Research and Extension Center, Scottsbluff to examine the magnitude of potential N losses from the soil system in form of nitrous oxide (N₂O) emissions, ammonia (NH₃) volatilization or nitrate (NO₃^-) leaching after the addition of char. In total, 48 soil columns (chamber with diameter of 5 cm and height of 30 cm each) will be packed with topsoil up to depth of 24 cm. A randomized complete block design with 2 different soil types, sandy loam and loamy silt loam, and 6 different rates of char: 0, 6.8, 13.6, 20.4, 27.2 and 34 t ha^-1 of C will be quadruplicated. Treatments effect on N₂O emissions, NH₃ volatilization and NO₃^-leaching will be periodically measured for 30 days, while maintaining the soil columns at field conditions for moisture and temperature. Additionally, residual N in soil will be measured at the end of experiment. Analysis of variance and least significant difference tests will be conducted to test for soil types, char rates and their interaction effects on different variables. The results of this study will generate data for better understanding of soil N dynamics in terms of N losses and residual N from different rates of char application. Furthermore, this study will provide insights necessary to initiate a field research to evaluate potential agricultural use of char as soil amendment.

Keywords: high carbon char, char, N mineralization, soil amendments, soil quality