Soil Management for Integrated Crop-Livestock Systems
Soil Compaction by Livestock
Many crop producers are concerned that cattle trampling will adversely affect soil physical properties and subsequent crop productivity. Soil compaction, measured as an increase in bulk density or penetration resistance, influences the ability of a plant to acquire water, nutrients, and oxygen because of restricted soil water movement, oxygen and nutrient diffusion to roots, and root growth, consequently reducing crop yield. Grazing in late fall, winter, or early spring can result in detectable compaction. However, the effects are usually confined to the upper 0 to 2 inches of soil depth and can be short-lived due to the natural processes of wetting-drying cycles, freezing-thawing cycles, root growth, and the activities of soil organisms. Therefore, grazing generally has no impact on subsequent crop yields.
Soil Organic Matter
Soils with higher levels of organic matter are more resistant to compaction because of greater capacity for soil particles to bind and maintain intact soil aggregates and the lower bulk density of organic materials. Soil organic matter provides elasticity and improves soil resilience. For example, accumulation of soil organic matter through long-term manure applications and cover crops can significantly reduce soil’s susceptibility to compaction.
Tillage
Conservation tillage systems (such as no-till) that cause little soil disturbance and maintain aggregate stability is less prone to subsequent compaction compared with deep disking and other intensive tillage practices. Animal traffic is mostly between rows and planting over or near the previous row further reduces concerns of compaction. In exceptional compaction cases, such as in areas of animal congregation, reduced tillage to a depth of 4 inches may be used to reduce soil bulk density and increase the water infiltration rate after grazing
Minimizing Effects of Soil Compaction
Soil compaction by livestock and associated soil disturbances are minimized under the following conditions when grazing crop residues: (1) grazing is restricted to periods when soils are dry or frozen, (2) in colder regions, multiple freeze-thaw cycles during the winter alleviate surface compaction, (3) soils containing high surface organic matter buffer the impact of cattle traffic, (4) proper stocking density, and (5) rotational grazing.
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