Impact of Tillage and Residue Burning on Carbon Dioxide Flux in a Wheat-Soybean Production System

• Published in: Soil Science Society of America journal Vol. 70; no. 4; pp. 1145 - 1154
• Main Authors: Brye, K.R, Longer, D.E, Gbur, E.E
• Format: Journal Article
• Language: English
• Published: Madison Soil Science Society 01-07-2006; American Society of Agronomy
• Subjects: Agricultural management; Agronomy; burning; Carbon dioxide; Cereal crops; Crop production; crop residue management; Crop residues; Environmental factors; fertilizer application; Fluctuations; gas emissions; Glycine max; greenhouse gases; Growing season; nitrogen; Plowing; Residues; soil; Soil moisture; Soil surfaces; Soil temperature; soil water content; Soybeans; subhumid zones; surface layers; Tillage; Triticum aestivum; Wheat; Arkansas; United States > US; ASW, USA, Mississippi R. Delta; USA, Arkansas
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj2005.0151

Burning of wheat (Triticum aestivum L.) residue followed by plowing is a common management practice in wheat-soybean [Glycine Max (L.) Merrill] production systems in the mid-southern USA. However, this residue management practice is not environmentally friendly and may not be sustainable. The objectives of this study were to (i) evaluate the effects of N fertilization of wheat, residue burning, and tillage on soil surface carbon dioxide (CO₂) flux in a wheat-soybean double-crop production system, and (ii) evaluate the role of soil temperature and soil moisture in controlling CO₂ flux in a relatively warm, subhumid environment. Soil surface CO₂ flux was measured nine times between June 2002 and October 2003 during the soybean growing season under all combinations of conventional- (CT) and no-tillage (NT) at high and low N fertilization levels with and without residue burning at two locations in the Mississippi River delta region of eastern Arkansas. Soil surface CO₂ flux was 37.6% higher (P < 0.01) from CT than from NT and 6.1% higher (P < 0.05) from the low than the high N rate treatment at one location, but not at the other. Burning did not affect soil surface CO₂ flux except for a significant burning x N rate (P = 0.016) and burning x time interaction (P = 0.032) at one location, but not at the other. Both soil temperature and moisture parameters were significantly negatively correlated with temperature-normalized soil surface CO₂ flux, but soil temperature, particularly at the 10-cm depth, explained more of the variation than did soil moisture parameters. The results of this study indicate that tillage and N fertilization of prior wheat, but not residue burning, affect the loss of C as CO₂ from the soil and that there are additional soil and/or environmental factors, other than near-surface soil moisture and temperature fluctuations, perhaps microbial biomass, that contribute to controlling soil surface CO₂ flux in wheat-soybean production systems in the subhumid region of southern USA.