Soil CO2 fluxes following tillage and rainfall events in a semiarid Mediterranean agroecosystem: Effects of tillage systems and nitrogen fertilization

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2010-10, Vol.139 (1-2), p.167-173
• Main Authors: MORELL, F. J, ALVARO-FUENTES, J, LAMPURLANES, J, CANTERO-MARTINEZ, C
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Carbon dioxide; Conservation tillage; Cropping systems. Cultivation. Soil tillage; Disturbances; Fertilization; Fluxes; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Hordeum vulgare; New technology; Nitrogen, phosphorus, potassium fertilizations; Rainfall; Soil (material); Soil tillage; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Tillage; Tillage. Tending. Growth control
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2010.07.015

Immediate burst of soil CO2 after tillage was related to degree of soil disturbance. Cumulated fluxes after tillage operations were reduced and similar among treatments. Cumulated fluxes after rainfall events were high and depended on tillage system. N fertilization led to little increases on soil CO2 flux. The increase of soil CO2 was related to the soil temperature on a no-tillage system. The response of soil CO2 flux to tillage operations and rainfall events was studied under semiarid Mediterranean conditions. The study was conducted on a barley monoculture agro-ecosystem during summer/autumn fallow periods in four consecutive years (2005-2008). The study compared three N fertilization levels (zero, medium; 60kgNh super(-1); high, 120kgNh super(-1)) under three tillage systems (NT, no-tillage; MT, minimum tillage; CT, conventional tillage). Tillage operations led to a pulse of soil CO2 flux. This pulse was linearly related to soil CO2 flux on the day before tillage operations under MT (slope=4.22) and CT (slope=16.7), indicating the extent of soil disturbances. However, the associated soil CO2-C losses during tillage operations were reduced and similar among different tillage systems. The soil CO2 flux after rainfall was higher under NT, where it was linearly related to soil temperatures (0.15-soil temperature-1.06). Soil CO2 fluxes decreased on the following days as the soil dried. N fertilization affected CO2 flux in 5 out of 35 observation days, with higher fluxes with N fertilization under conservation tillage systems. Emissions after rainfall events led to large soil CO2-C losses, and these were of higher magnitude under conservation tillage systems (NT and MT).