Journal Article

Temporal Changes in Soil Surface Elevation under Different Tillage Systems

Curtin, Denis, Fraser, Patricia M, Beare, Michael H, Meenken, Esther D, Gillespie, Richard N

2010

Overview

Conventional, fixed-depth sampling may lead to errors in quantifying temporal changes in C stocks if soil bulk density (BD) changes. When surface elevation is altered due to a change in BD, sampling depth should be adjusted so that the sampled soil mass remains constant. We evaluated the ability of a topographic survey method (precise level) to quantify temporal changes (2000–2007) in surface elevation following conversion of long-term pasture to arable cropping using conventional tillage (plowing to 20 cm), minimum tillage, or no-till. Measured elevations were compared with values estimated from BD determined for fixed-depth increments (0–7.5, 7.5–15, 15–25, and 25–30 cm). In the first season, soil mass to 25 cm decreased by ?270 Mg/ha under conventional cultivation (relative to precultivation mass of 3345 Mg/ha) as BD decreased in the 7.5- to 15- and 15- to 25-cm layers. This represented an upward movement of the soil surface by an estimated 22 mm. Minimum tillage and no-till treatments moved 9 and 2 mm upward, respectively. Subsequently, the soil consolidated and surface elevation declined by an estimated 8 mm in all cultivated treatments. Elevation changes measured by the precise level were very similar to these BD-based estimates. Changes in elevation in conventional, minimum tillage, and no-till treatments averaged 13, 1.5, and −6 mm, respectively (positive values indicate upward movement, negative values subsidence). Corresponding BD-estimated values were 17, 1.1, and −3 mm. Using topographic survey information, sampling depth can be adjusted so that a constant mass is sampled from soils where BD has been changed by tillage or natural processes.

• Publisher: Soil Science Society,Soil Science Society of America,American Society of Agronomy
• Subject: Adjustment / agricultural land / Agronomy. Soil science and plant productions / Biological and medical sciences / bulk density / Carbon / conventional tillage / Cropping systems. Cultivation. Soil tillage / Earth sciences / Earth, ocean, space / Elevation / Exact sciences and technology / Fundamental and applied biological sciences. Psychology / General agronomy. Plant production / land use change / Loam soils / Magnesium / Methods / microrelief / minimum tillage / Movement / no-tillage / Pasture / pastures / Plowing / Sampling / Soil (material) / soil compaction / Soil density / soil depth / soil organic carbon / Soil science / Soil surfaces / Soil tillage / Soils / Surficial geology / Temporal logic / temporal variation / Tillage / Tillage. Tending. Growth control