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ARS Home » Research » Publications at this Location » Publication #280584
Title: Crop rotation effect on soil carbon and nitrogen stocks under limited irrigation

Author
item Halvorson, Ardell
item SCHLEGEL, ALAN - Kansas State University Extension Center

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2012
Publication Date: 6/21/2012
Citation: Halvorson, A.D., Schlegel, A.J. 2012. Crop rotation effect on soil carbon and nitrogen stocks under limited irrigation. Agronomy Journal. 104:1265-1273.

Interpretive Summary: Limited irrigation management practices are being used in the Central Great Plains to conserve water by optimizing crop water use efficiency. Limited irrigation may reduce total crop biomass production and amount of crop residue returned to the soil. Crop residue production within four no-till (NT) crop rotations [continuous corn (CC); corn-winter wheat (CW); corn-winter wheat-grain sorghum (CWS); corn-winter wheat-grain sorghum-soybean (CWSSb)] was measured and changes in soil organic carbon (SOC) and total soil nitrogen (TSN) stocks were monitored for 10 yr. Crop residue and residue N and C returned to the soil varied with crop being produced and with rotation. SOC and TSN stocks increased with time in all rotations. The rate of change in SOC and TSN mass for the CC, CW, CWS, and CWSSb rotations was 0.717, 0.477, 0.335, and 0.270 Mg SOC ha-1 yr-1 and 0.114, 0.092, 0.087, and 0.084 Mg TSN ha-1 yr-1, respectively, in the 0-30.5 cm soil depth. The rate of change in SOC and TSN mass was associated with the amount of annual residue being returned to the soil with CWSSb having the lowest residue production (8.66 Mg residue ha-1yr-1) and CC the highest (11.95 Mg residue ha-1yr-1). Approximately 6.8 to 7.6 Mg residue ha-1yr-1 would be needed to maintain SOC stocks under limited irrigation.

Technical Abstract: Limited irrigation management practices are being used in the Central Great Plains to conserve water by optimizing crop water use efficiency. Limited irrigation may reduce total crop biomass production and amount of crop residue returned to the soil. Crop residue production within four no-till (NT) crop rotations [continuous corn (Zea mays L.) (CC); corn-winter wheat (Triticum aestivum L.) (CW); corn-winter wheat-grain sorghum (Sorghum bicolor L. Moench) (CWS); corn-winter wheat-grain sorghum-soybean (Glycine max L.) (CWSSb)] was measured and changes in soil organic carbon (SOC) and total soil nitrogen (TSN) stocks were monitored for 10 yr. Crop residue yields varied with crop being produced and with rotation, as did residue N and C returned to the soil. The C:N ratio of the residue varied with crop. The SOC and TSN pools increased with time in all rotations. The rate of gain in SOC and TSN mass for each rotation was 0.717, 0.477, 0.335, and 0.270 Mg SOC ha-1 yr-1 and 0.114, 0.092, 0.087, and 0.084 Mg TSN ha-1 yr-1 for the CC, CW, CWS, and CWSSb rotations, respectively, in the 0-30.5 cm soil depth. The rate of change in SOC and TSN mass was lowest with CWSSb (8.66 Mg residue ha-1yr-1) and highest with CC (11.95 Mg residue ha-1yr-1). Approximately 6.8 to 7.6 Mg residue ha-1yr-1 would be needed to maintain SOC stocks under limited irrigation.