title: A comparison of corn (Zea mays L.) residue and its biochar on soil C and plant growth.
abstract: In order to properly determine the value of charring crop residues, the C use efficiency and effects on crop performance of biochar needs to be compared to the un-charred crop residues. In this study we compared the addition of corn stalks to soil, with equivalent additions of charred (300 °C and 500 °C) corn residues. Two experiments were conducted: a long term laboratory mineralization, and a growth chamber trial with proso millet plants. In the laboratory, we measured soil mineral N dynamics, C use efficiency, and soil organic matter (SOM) chemical changes via infrared spectroscopy. The 300 °C biochar decreased plant biomass relative to a nothing added control. The 500°C biochar had little to no effect on plant biomass. With incubation we measured lower soil NO3 content in the corn stalk treatment than in the biochar-amended soils, suggesting that the millet growth reduction in the stalk treatment was mainly driven by N limitation, whereas other factors contributed to the biomass yield reductions in the biochar treatments. Corn stalks had a C sequestration use efficiency of up to 0.26, but charring enhanced C sequestration to values that ranged from 0.64 to 1.0. Infrared spectroscopy of the soils as they mineralized showed that absorbance at 3400, 2925-2850, 1737 cm-1, and 1656 cm-1 decreased during the incubation and can be regarded as labile SOM, corn residue, or biochar bands. Absorbances near 1600, 1500-1420, and 1345 cm-1 represented the more refractory SOM moieties. Our results show that adding crop residue biochar to soil is a sound C sequestration technology compared to letting the crop residues decompose in the field. This is because the resistance to decomposition of the chars after soil amendment offsets any C losses during charring of the crop residues.
authors.affiliation: USDA-ARS, 40335 Co Rd GG., Central Great Plains Research Station, Akron, Colorado, United States of America.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Calderón
authors.affiliation: USDA-ARS, 40335 Co Rd GG., Central Great Plains Research Station, Akron, Colorado, United States of America.
authors.forename: Joseph
authors.initials: J
authors.lastname: Benjamin
authors.affiliation: USDA-ARS, 40335 Co Rd GG., Central Great Plains Research Station, Akron, Colorado, United States of America.
authors.forename: Merle F
authors.initials: MF
authors.lastname: Vigil
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism; D002606:Charcoal / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006358:Hot Temperature; D017745:Incineration; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism; D008897:Panicum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D003313:Zea mays / Q000737:chemistry*
chemical_list: D012987:Soil; C540010:biochar; D002606:Charcoal; D002244:Carbon; D009584:Nitrogen
references.citation: Appl Spectrosc. 2008 Feb;62(2):182-9
references.pmid: 18284794
references.citation: J Agric Food Chem. 2013 Mar 6;61(9):2196-204
references.pmid: 23343098
references.citation: Appl Spectrosc. 2012 Jun;66(6):689-95
references.pmid: 22732541
references.citation: J Environ Qual. 2012 Jul-Aug;41(4):1033-43
references.pmid: 22751045
references.citation: Chemosphere. 2012 Nov;89(11):1467-71
references.pmid: 22763330