Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2004
Publication Date: July 28, 2004
Citation: Reicosky, D.C., Archer, D.W., Wente, C.D. 2004. Spatial variability in carbon dioxide loss after moldboard plowing within a soil map unit. [abstract]. Seventh International Conference on Precision Agriculture Conference Abstracts. p. 79. Technical Abstract: Significant reduction in soil organic matter due to long-term cultivation has occurred in nearly all agricultural ecosystems that are composed of many different soil types that likely require site-specific management. Quantifying the organic matter dynamics in similar soil types is fundamental to identifying the pathways for C sequestration and increasing soil C pools to reduce the buildup of atmospheric CO2. The objective was to quantify the two-dimensional spatial variability in tillage-induced CO2 loss immediately after fall plowing on a uniform soil type (Hamerly clay loam (Aeric Calciaquoll)) cropped to spring wheat (Triticum aestivum L.) in 2001. Twenty-five plots in a five by five, uniformly-spaced parallel transects (55m long by 2.7m wide) were pre-marked. For each transect, the moldboard plow was pulled through each plot area, stopped and gas exchange measurements initiated within one minute using a large portable chamber. This process was sequentially repeated for each location along all transects for 0.5 and 24 hours after tillage. Variation in surface soil water content, soil C content, and the CO2 loss along each transect were measured. Initial CO2 flux values were large and showed a rapid decline within the first five hours. Initial differences in CO2 flux due to soil location were significant and often were related to soil C content. As CO2 flux decreased with time, differences due to soil spatial variability also decreased. Simple correlation analysis showed a strong correlation between cumulative CO2 flux and surface soil C content. The results demonstrate a significant variation in C loss across the landscape as a result of moldboard plowing related to spatial variation within a uniform soil map unit. Understanding variation in greenhouse gas emission related to soil type and tillage methods will enable intelligent policy decisions for improved environmental quality.