Agroecosystem management effects on soil carbon and nitrogen

• Published in: Agriculture, ecosystems & environment Vol. 39; no. 3; pp. 123 - 138
• Main Authors: Wood, C.W., Edwards, J.H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1992; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; azote; Biological and medical sciences; carbon; carbone; carbono; Cropping systems. Cultivation. Soil tillage; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; glycine max; labranza; mineralisation; mineralizacion; mineralization; nitrogen; nitrogeno; rotacion de cultivos; rotation culturale; rotational cropping; tillage; travail du sol; triticum aestivum; zea mays; Alabama; United States; North America; America; Organic carbon; Cultural practice; Subtropical zone; Soil tillage; Long term test; Cropping system; Soil management; Agroecosystem; Carbon cycle; Soils; Nitrogen cycle; Mineralization; Crop rotation; Conservation tillage; Ultisols; Sandy loam soil
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/0167-8809(92)90048-G

The cumulative effects of long-term (1980–1990) tillage and crop rotation management on soil organic C and N concentrations and potential mineralization were determined. Tillage systems studied were conventional moldboard plow tillage and conservation tillage, with various crop rotations including: continuous soybean ( Glycine max L.)-wheat ( Triticum aestivum L.) cover (SW); continuous corn ( Zea mays L.)-wheat cover (CW); and corn-wheat cover-soybean-wheat cover (CWSW). Surface soil (0–5, 5–10, and 10–20 cm depth increments) organic C and N concentrations and potential mineralization were determined for all tillage/rotation combinations in October 1990. After 10 years, surface soil organic C and N concentrations were 67% and 66% higher, respectively, under conservation tillage than plow tillage to a depth of 10 cm. Potential C and N mineralization followed a pattern similar to organic C and N distribution. However, differences in substrate quality below 10 cm indicated that conservation tillage promoted N immobilization. Crop rotation had less effect than tillage on soil organic C and N amounts and potential mineralization. Rotations with higher frequency of corn (CW and CWSW) had higher organic C and N concentrations and C mineralization than SW; crop rotation had no effect on potential N mineralization. Tillage system apparently influenced soil organic matter concentrations and mineralization via crop residue incorporation rather than any effects owing to concentration differences at the soil surface, while the effect of crop rotation was related to amount of crop residues added between 1980 and 1990.