ARS | Publication request: Can southern US rice cultivars be used to mitigate greenhouse gas emissions? A preliminary study.

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 27, 2011
Publication Date: February 27, 2012
Citation: Mcclung, A.M., Anders, M., Adviento-Borbe, A., Bryant, R.J., Linquist, B., Van Kessel, C. 2012. Can southern US rice cultivars be used to mitigate greenhouse gas emissions? A preliminary study. Proceedings of the 34th Rice Technical Working Group Meeting, February 27- March 1, 2012, Hot Springs, Arkansas. p.149.

Technical Abstract: Most rice in the world is produced under flooded paddy conditions as a means of producing high stable yields and controlling non-aquatic weeds. However, the anaerobic soil conditions that occur as a result of the flooded fields cause high levels of methane production due to bacterial methanogenesis. Because rice feeds about half of the world’s population, the expansive global acreage results in rice contributing 10-20% of global methane emissions. Nitrous oxide is another gas associated with global warming and its presence is, in part, a result of the application of nitrogen based fertilizers in agriculture. We conducted a replicated study in Stuttgart, AR during 2011 to determine season long greenhouse gas emissions as a result of fertilizer application rates and timing using one rice cultivar. In addition, a small exploratory study was conducted to determine the potential that choice of variety may play in mitigating greenhouse gas emissions from rice production fields. The study was conducted adjacent to the fertilizer-rate study and included five public varieties and one hybrid (CLXL751). The varieties included Jupiter – conventional medium grain variety, Francis and Roy-J – conventional long grain varieties, and Rondo and Sabine – specialty long grain varieties. In addition, Francis and Rondo are parents of a mapping population developed by Wengui Yan which captures indica x japonica genomic interactions. The objective in this preliminary study was to determine if cultivars differed for season long greenhouse gas emission profiles that could be used as a component in mitigation efforts. In addition, the inclusion of the mapping population parents provided the opportunity of possibly mapping traits and genes associated with greenhouse gas emissions in the future. Each variety was drill seeded in a standard size yield plot. After planting, a static flux vented chamber was placed in each cultivar field plot. Gas samples were collected from within the chambers approximately twice a week throughout the growing season and nitrous oxide and methane emissions were determined. In addition, various plant growth parameters and grain yield were determined. Results will be presented that demonstrate major differences between the methane emissions of the tropical japonica cultivars (Francis, Sabine and Roy-J) in comparison to Rondo (indica), Jupiter (temperate japonica) and the hybrid. Even though there was a twelve day difference in heading among the six cultivars, the emission profile appeared to be independent of maturity factors.