Optimum rates of surface-applied coal char decreased soil ammonia volatilization loss

Authors

Dinesh Panday, University of Nebraska-LincolnFollow
Maysoon M. Mikha, USDA-ARS, Central Great Plains Research Station, Akron, COFollow
Harold P. Collins, USDA-ARS, Grassland Soil and Water Research Laboratory, Temple, TXFollow
Virginia L. Jin, USDA-ARS, Agroecosystem Management Research Unit, Lincoln, NEFollow
Michael Kaiser, University of Nebraska - LincolnFollow
Jennifer Cooper, University of Nebraska - LincolnFollow
Arindam Malakar, University of Nebraska - LincolnFollow
Bijesh Maharjan, University of Nebraska - LincolnFollow

ORCID IDs

Dinesh Panday https://orcid.org/0000-0001-8452-3797

Arindam Malakar https://orcid.org/0000-0001-6704-8891

Bijesh Maharjan https://orcid.org/0000-0002-4728-7956

Date of this Version

3-15-2020

Comments

J. Environ. Qual. 2020;49:256–267.

DOI: 10.1002/jeq2.20023

Abstract

Fertilizer N losses from agricultural systems have economic and environmental implications. Soil amendment with high C materials, such as coal char, may mitigate N losses. Char, a coal combustion residue, obtained from a sugar factory in Scottsbluff, NE, contained 29% C by weight. A 30-d laboratory study was conducted to evaluate the effects of char addition on N losses via nitrous oxide (N₂O) emission, ammonia (NH₃) volatilization, and nitrate (NO₃–N) leaching from fertilized loam and sandy loam soils. Char was applied at five different rates (0, 6.7, 10.1, 13.4, and 26.8 Mg C ha⁻¹; char measured in C equivalent) to soils fertilized with urea ammonium nitrate (UAN) at 200 kg N ha⁻¹. In addition, there were two negative-UAN control treatments: no char (no UAN) and char at 26.8 Mg C ha⁻¹(no UAN). Treatment applied at 6.7 and 10.1Mg C ha₋₁ in fertilized sandy loam reduced NH₃ volatilization by 26– 37% and at 6.7, 10.1, and 13.4 Mg C ha⁻¹in fertilized loam soils by 24% compared with no char application. Nitrous oxide emissions and NO₃–N leaching losses were greater in fertilized compared with unfertilized soil, but there was no effect of char amendment on these losses. Because NO₃–N leaching loss was greater in sandy loam than in loam, soil residual N was twofold higher in loam than in sandy loam. This study suggests that adding coal char at optimal rates may reduce agricultural reactive N to the atmosphere by decreasing NH₃ volatilization from fertilized soils.