Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 9/1/1999
Publication Date: N/A
Citation: Prior, S.A., Reeves, D.W., Rogers, H.H., Torbert, H.A., and Dugas, W.A. 1999. Effects of elevated atmospheric CO2 on agroecosystems: Conventional vs. sustainable cropping system. Proceedings of the Global Change and Terrestrial Ecosystems Focus 3 Conference: Food & Forestry: Global Change and Global Challenges. p. 121-122. The University of Reading, UK. September 20-23. Interpretive Summary:
Technical Abstract: Increasing atmospheric CO2 concentration has led to concerns about potential changes to production agriculture as well as agriculture's role in sequestering C. This study was initiated (fall 1997) to compare the effects of elevated CO2 on two cropping systems (conventional and sustainable). The study used a split-plot design replicated three times with two cropping systems as main plots and two CO2 levels (360 and 720 ppm) as subplots using open top field chambers on a Decatur silt loam. The conventional systems consists of a grain sorghum [Sorghum bicolor (L.) Moench.] and soybean [Glycine max (L.) Merr.] rotation using conventional tillage practices and winter fallow. In the sustainable system, sorghum and soybean were rotated and three cover crops were used [crimson clover (Trifolium incarnatum L.), sun hemp (Crotalaria juncea L.) and wheat (Triticum aestivum L.)] using no till practices. The sustainable system has either cash or cover crops grown throughout the year with no fallow periods (in order of: clover, sorghum, sun hemp, wheat, soybean). Under high CO2, biomass production of clover and sun hemp was increased 24 and 32%, respectively. Sorghum grain yield was not affected by CO2 level, however, stover production was increased 14% due to elevated CO2. The sustainable system had a small increase in sorghum grain yield (6%) relative to the conventional system; a similar trend was noted for stover production. Results suggest that CO2-induced increases in non-yield biomass for the sustainable system will increase both soil C inputs and ground coverage, thereby potentially improving soil chemical and physical properties.