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LSP Report LS7013

Improving the Degraded Structure of a Clay Loam Soil
with Deep Tillage and Grass and Legume Crops


 

Researchers: W. Curnoe, KCAT, J. Culley, L. Heslop and N. McLaughlin, Agriculture Canada, Principal Researchers

Funding: $79,180

Objectives

  1. To develop agronomic practices which restore the productivity of fine textured soils which have been seriously degraded as a result of continuous corn cropping with conventional tillage.

Expected Benefits

  1. To provide primary producers with good quality information from which they will be able to evaluate benefits and costs related to crop-based and tillage-based remedial measures for improving degraded soil tilth.

Summary of Research Results

A no-tillage system was imposed on a structurally degraded fine-texture soil (Humic Gleysol) that had been under continuous corn with moldboard tillage for more than 20 years. After 3 years of no-tillage, several soil structural properties were compared with the conventional tillage treatment to assess whether the soil structure had improved.

No significant difference (P < 0.05) was found between tillage treatments for the saturated hydraulic conductivity, porosity and penetration resistance in the surface 5 cm. Measurements of soil penetration resistance and in situ saturated hydraulic conductivity (Kwp) using the well permeameter method were sensitive structural changes that had occurred at 5-20 cm depth. The Kwp at this depth was significantly greater in the moldboard treatment than in the no-tillage treatment. Resistance measurements indicated significantly greater soil strengths at 10-20 cm under no-tillage. Aggregate stabilities were assessed by wet sieving twice during the growing season. No-tillage resulted in larger soil aggregates, especially at the surface, compared with the moldboard tillage.

These data suggest that degraded soils with low structural stability may initially suffer further deterioration with the elimination of tillage, owing to the loss or reduction of mechanically formed pores.

 

 

 

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Created: 03-23-1996
Last Revised: Tuesday, May 10, 2011 12:55:49 PM