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Tillage to incorporate and prepare
Tillage accelerates decomposition of crop residues, compost and animal manures into soil organic matter. Successful incorporation tillage:
• Encourages the rapid growth of soil organisms, given sufficient warmth and moisture, by adding extra nitrogen, oxygen and carbon to their environment. (Organically managed soils encourage soil animal predators that feed on weed seeds, helping to lower weed pressure.)
• Increases soil contact with plant and manure residues. By breaking down residue into smaller pieces, incorporation increases the surface area for microbes to contact, consume and digest the materials
• Decreases the bulk density of the soil, promoting both drainage in wet times and moisture-holding capacity during drought.
• Deepens the aerobic (oxygenated) soil layer that is rich in microbial activity due to favorable temperature and moisture conditions.
• Helps maintain soil tilth in the upper horizon when soil is worked at the proper moisture content and receives sufficient organic residue.
The goal of tilling for seedbed preparation is to work the topsoil just enough to allow optimum seedling vigor. Successful seedbed preparation provides:
• Good seed-to-soil contact in firm, moist soil for vigorous seed germination and root development.
• Sufficient soil aeration for plant growth without creating large voids and clods and without stirring soil any more than necessary.
• Warmer soil to enhance seed germination. Bare soil warms faster than mulched soil but is vulnerable to erosion and moisture loss.
The “stale seedbed” technique uses a series of light cultivations to sprout weed seeds, then tills them, exhausting the surface weed supply.
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Careful tillage incorporates crop residues, in this case alfalfa, into the soil without pulverizing soil aggregates or overly disturbing the microbial community. The incorporated plant residues feed the microbes in the soil, which in turn feed the next crop planted. (Photo: TRI)
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