Six soil pedons on the Highland Rim near Springfield, TN were sampled for carbon content. The objective was to determine if continuous additions of manure altered the amount of carbon sequestered in cultivated soils compared to uncultivated soils. Pedons 3, 4, 5, and 6 had been fertilized continuously for twenty-eight years at a rate of 336 kg N ha-1, 112 kg P ha-1, and 336 kg K ha-1. Additionally, pedons 5 and 6 received 22.4 Mg ha-1 of manure. Pedons 1 and 2 were uncultivated soils located near the fertility plots. Soil pedons were sampled and described using National Cooperative Soil Survey methods. Total carbon analysis was measured with a Leco CR 12. Averaged over the thickness of the A/Ap horizons, the uncultivated pedons 1 and 2 reflected extremes in carbon means of 1.08% and 0.78%, respectively. Pedons 3 and 4, which received only fertilizers, averaged 0.97% and 0.73% C, respectively. Pedons 5 and 6, which received the additional manure, had averaged carbon levels of 0.89% and 0.85%, respectively. Average carbon content in horizons below the A/Ap to a depth of 50cm indicated higher sequestration of carbon in the native soils of Pedon 1 (0.51%) and 2 (0.45%) , compared to the cultivated soils, Pedon 3 (0.22%), Pedon 4 (0.26%), Pedon 5 (0.19%), and Pedon 6 (0.20%). A similar trend occurred between 50 cm and 100 cm with carbon levels higher in Pedon 1 (0.19%) and 2 (0.20%) and substantially lower in Pedon 3 (0.13%), Pedon 4 (0.10%), Pedon 5 (0.10%), and Pedon 6 (0.13%). The addition of manure in cultivated plots resulted in no significant influence in sustaining the amount of carbon sequestered with depth in these soils.
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