Impact of switchgrass biochars with supplemental nitrogen on carbon-nitrogen mineralization in highly weathered Coastal Plain Ultisols. (February 2016)

• Record Type: Journal Article
• Authors: Sigua, G.C.; Novak, J.M.; Watts, D.W.; Szögi, A.A.; Shumaker, P.D.
• Is Part Of: Chemosphere. Volume 145(2016)
• Page Start: 135
• Page End: 141
• Publication Date: 2016-02
• Subjects: Switchgrass biochars -- Switchgrass residues -- Carbon mineralization -- Highly weathered soils -- Coastal Plain Ultisols -- Total inorganic nitrogen; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.11.063
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Although an increase in soil fertility is the most frequently reported benefit linked to adding biochar to soils, there is still a need to pursue additional research that will improve our understanding on the impact of soil fertility enhancement because the effect could vary greatly between switchgrass ( Panicum virgatum, L) residues (USG) and switchgrass biochars (SG). We hypothesized that SG with supplemental nitrogen (N) would deliver more positive effects on carbon (C) and N mineralization than USG. The objective of this study was to evaluate the effects of USG and SG, with or without supplemental inorganic N fertilizer on C and N mineralization in highly weathered Coastal Plain Ultisols. The application rate for SG and USG based on a corn yield goal of 112 kg ha −1 was 40 Mg ha −1 . Inorganic N was added at the rate of 100 kg N ha −1, also based on a corn yield of 7.03 tons ha −1 . Experimental treatments were: control (CONT) soil; control with N (CONT + N); switchgrass residues (USG); USG with N (USG + N); switchgrass biochars at 250 °C (250SG); SG at 250 °C with N (250SG + N); SG at 500 °C (500SG); and SG at 500 °C with N (500SG + N). Cumulative and net CO2 –C evolution was increased by the additions of SG and USG especially when supplemented with N. Soils treated with 250SG (8.6 mg kg −1 ) had the least concentration of total inorganic nitrogen (TIN) while the greatest amount of TIN was observed from the CONT + N (19.0 mg kg −1 ). Our results suggest that application of SG in the short term may cause N immobilization resulting in the reduction of TIN. Highlights: Carbon dioxide evolution was increased by the additions of switchgrass biochars and residues. Application of switchgrass biochar may cause N immobilization. Biochar application may need supplemental N to avoid crop growth retardation.