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United States Department of Agriculture

Agricultural Research Service

Research Project: Development of Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research Unit

Title: Soil carbon and nitrogen affected by perennial grass, cover crop, and nitrogen fertilization

Authors
item Sainju, Upendra
item Singh, Bharat -
item Singh, Hari -

Submitted to: World Congress of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2014
Publication Date: N/A

Technical Abstract: Soil C and N sequestration and the potential for N leaching can be influenced by the type of perennial grass, cover crop, and N fertilization due to differences in crop yields and the amount of residue returned to the soil. We evaluated the effects of the combinations of perennial grasses (energy cane vs. elephant grass), cover crops (clover cover crop vs. none), and N fertilization rates (0, 100, and 200 kg N ha-1) on soil organic C, total N, NH4-N, and NO3-N concentrations at the 0-90 cm depth from 2011 to 2012 in central Georgia. Soil organic C at 15-30 cm and total N at 0-5 cm were greater for elephant grass with cover crop and 100 kg N ha-1 than for energy cane and elephant grass with no cover crop and N fertilization. In contrast, soil NO3-N at 0-5 cm was lower for energy cane with no cover crop and N fertilization than for energy cane with cover crop and 100 to 200 kg N ha-1. Elephant grass increased soil total N at 0-5 cm compared to energy cane. Cover crop increased soil organic C at 5-30 cm, total N at 5-15 cm, and NO3-N at 15-30 cm compared to no cover crop. Nitrogen fertilization increased soil organic C and total N at 0-5 cm and NO3-N compared to no N fertilization, but soil organic C at 15-30 cm was lower with 200 than with 100 kg N ha-1. Soil organic C, total N, and NO3-N decreased from 2011 to 2012, regardless of treatments. Preliminary results suggest that elephant grass with clover cover crop and 100 kg N ha-1 can sequester more soil C and N than other treatments and increased N fertilization rate can increase the potential for N leaching.

Last Modified: 9/22/2014
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