Soil carbon dioxide and methane fluxes as affected by tillage and N fertilization in dryland conditions

• Published in: Plant and soil 2014-08, Vol.381 (1-2), p.111-130
• Main Authors: Plaza-Bonilla, Daniel, Cantero-Martínez, Carlos, Bareche, Javier, Arrúe, José Luis, Álvaro-Fuentes, Jorge
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agricultural site preparation; Agricultural soils; agroecosystems; Agronomy. Soil science and plant productions; Analysis; Animal wastes; Animal, plant and microbial ecology; arid lands; Arid zones; Biological and medical sciences; biomass; Biomedical and Life Sciences; Carbon dioxide; Carbon dioxide emissions; carbon sinks; Chemical properties; Chemical, physicochemical, biochemical and biological properties; Crop yield; Cropping systems. Cultivation. Soil tillage; Ecology; emissions; Environmental aspects; Fertilization; fertilizer rates; Fertilizers; field experimentation; Field tests; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grain yield; Life Sciences; long term experiments; Methane; methane production; Minerals; Nitrogen fertilization; nitrogen fertilizers; Nitrogen, phosphorus, potassium fertilizations; No-tillage; Organic carbon; Organic matter; Organic soils; oxidation; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Pig manure; Plant Physiology; Plant Sciences; Regular Article; Slurries; soil; Soil biochemistry; soil organic carbon; Soil science; Soil Science & Conservation; Soil tillage; Soil water; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Tillage; Tillage. Tending. Growth control
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-014-2115-8

BACKGROUND AND AIMS: The effects of tillage and N fertilization on CO₂ and CH₄ emissions are a cause for concern worldwide. This paper quantifies these effects in a Mediterranean dryland area. METHODS: CO₂ and CH₄ fluxes were measured in two field experiments. A long-term experiment compared two types of tillage (NT, no-tillage, and CT, conventional intensive tillage) and three N fertilization rates (0, 60 and 120 kg N ha⁻¹). A short-term experiment compared NT and CT, three N fertilization doses (0, 75 and 150 kg N ha⁻¹) and two types of fertilizer (mineral N and organic N with pig slurry). Aboveground and root biomass C inputs, soil organic carbon stocks and grain yield were also quantified. RESULTS: The NT treatment showed a greater mean CO₂ flux than the CT treatment in both experiments. In the long-term experiment CH₄ oxidation was greater under NT, whereas in the short-term experiment it was greater under CT. The fertilization treatments also affected CO₂ emissions in the short-term experiment, with the greatest fluxes when 75 and 150 kg organic N ha⁻¹ was applied. Overall, the amount of CO₂ emitted ranged between 0.47 and 6.0 kg CO₂−equivalent kg grain⁻¹. NT lowered yield-scaled emissions in both experiments, but these treatment effects were largely driven by an increase in grain yield. CONCLUSIONS: In dryland Mediterranean agroecosystems the combination of NT and medium rates of either mineral or organic N fertilization can be an appropriate strategy for optimizing CO₂ and CH₄ emissions and grain yield.