Soil aggregation and organic carbon protection in a no-tillage chronosequence under Mediterranean conditions

Published source details Plaza-Bonilla D., Cantero-Martínez C., Viñas P. & Álvaro-Fuentes J. (2013) Soil aggregation and organic carbon protection in a no-tillage chronosequence under Mediterranean conditions. Geoderma, 193, 76-82.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Soil: Use no tillage in arable fields Action Link
	Change tillage practices Action Link

Soil: Use no tillage in arable fields

A replicated, randomized, controlled study in 1990–2010 in a winter cereal field in the Ebro river valley, Spain, found more organic matter and greater stability in soils with no tillage, compared to conventional tillage. The most organic matter and the greatest stability were found in soils with 11–20 years of no tillage. Organic matter: More organic carbon was found in soils with no tillage, compared to conventional tillage, in three of sixteen comparisons (0–5 cm depth: 17–24 vs 12 g C/kg soil). Soil erosion and aggregation: More water-stable macroaggregates (0.25–8 mm diameter) and fewer water-stable microaggregates (0.053–0.25 mm diameter) were found in soils with no tillage, compared to conventional tillage (macroaggregates, in eight of 32 comparisons, 0–10 cm depth: 0.12–0.32 vs 0.02–0.04 g aggregate/g dry soil; microaggregates, in six of 16 comparisons, 0–10 cm depth: 0.25–0.41 vs 0.44–0.50). More large, dry macroaggregates (2–8 mm diameter) were found in soils with no tillage, compared to conventional tillage, in three of 16 comparisons (10–20 cm depth: 0.52–0.56 vs 0.38–0.40 g aggregate/g dry soil). Fewer small, dry macroaggregates (0.25–2 mm) were found in soils with no tillage, compared to conventional tillage, in four of 16 comparisons (10 –30 cm depth: 0.27 – 0.32 vs 0.36–0.41 g aggregate/g dry soil). Implementation options: More organic carbon was found in soils with 11–20 years of no tillage, compared to 1–4 years, at one of four depths (0–5 cm depth: 24 vs 11–17 g C/kg soil). More large, water-stable macroaggregates (2–8 mm diameter) were found in soils with 11–20 years of no tillage, compared to 1–4 years, at one of four depths (0–5 cm depth: 0.30–0.32 vs 0.02–0.12 g aggregate/g dry soil). More small, water-stable macroaggregates were found in soils with 4–20 years of no tillage, compared to one year, at one of four depths (0–5 cm depth: 0.13–0.16 vs 0.04 g aggregate/g dry soil). More large, dry macroaggregates (2–8 mm diameter) and fewer small macroaggregates (0.25–2 mm diameter) were found in soils with 4–20 years of no tillage, compared to 0–1 year, at one of four depths (10–20 cm depth: large: 0.52–0.56 vs 0.38–0.40 g aggregate/g dry soil; small: 0.30–0.32 vs 0.39–0.41). Methods: No tillage was used on four plots for 1–20 years (beginning in 1990, 1999, 2006, and 2009). Conventional tillage was used on the same four plots, before no tillage began, and also on one control plot for 20 years (1990–2010). Plots were 1,500 m². Soil samples were collected in July 2010 with a flat spade (0–30 cm depth).
Change tillage practices

A randomized, experiment in 2010 on sandy loam soil in north-east Spain (Plaza-Bonilla et al. 2013) found that soil organic carbon levels were highest in soils which had been managed under no-till for 11 years (ranging from 7.1 to 24 g C/kg dry soil) compared to no-till for one year (8.9-10.5 g C/kg dry soil) and four years (8.5-20 g C/kg dry soil) respectively. The experimental field was 7500 m², and had previously been intensively tilled. Two crops (either wheat Triticum aestivum or barley Hordeum vulgare) were exposed to one of five treatments: conventional tillage (mouldboard plough, 1500 m²), no-till for one year, no-till for four years, no-till for 11 years, no-till for 20 years (the remaining 6000 m²). Pig slurry was applied across the whole experiment as fertilizer. From each treatment, three soil samples were taken in 2010 after crop harvest. Soil organic carbon levels were measured.