Tillage adaptability to soils
Soils interact with no-till, ridge-till, and mulch-till systems differently. Consequently,
choosing the right system for your farm can be difficult, especially when several soil types
exist in each cropland field. Several factors can have an impact on the success of conservation
tillage. While it's impractical to rate every soil type in the U.S. for adaptability to
conservation tillage systems, some general rules-of-thumb can be applied in determining
what system works the best on what soils:
 No-till should provide yields equal to
those of other systems for corn, soybeans, and wheat in the northern half of the U.S.
when crops are rotated and when used on naturally well-drained soils, or on sloping
land. No-till should provide better yield potential than other systems in the southern half
of the U.S., with rotations, well-drained (or tiled) soils, sloping land, or very low organic
matter soils. For no-tilling into an established sod or cover crop, it's important that
the cover is killed on a timely basis to ensure that adequate soil moisture is available for
the new crop.
Ridge-till systems should provide equal
or better yields for corn, soybeans, and sorghum than other systems, with or
without rotation, on prairie soils that are well tiled and have organic matter levels
of 3.5% or more and where row widths of 30 inches or wider are planted.
Mulch-till may be the system of choice
where there is great soil variation within a field, where preplant incorporated herbicides
are necessary, or where equipment management limitations preclude the use
of ridge-till or no-till.
Stubble mulching or no-till eco-fallow
should produce best yields in low-rainfall areas of the U.S. for wheat,
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A Georgia farmer uses this strip-till configuration on his planter. The coulters cut the
residue, and the long subsoil shanks break up soil compaction (common to sandy soils) while
keeping crop residue in place.
sunflower, and grain sorghum, provided proper stands can be established, weeds are controlled,
and crop rotation is used.
Until recent years, most no-till and ridge-till planting was performed with
rather specific operations-for no-till, one fluted coulter ahead of each planter unit,
for ridge-till, removal of residue and some bare soil in the row area at planting time.
Strip-till applications
While conservation tillage may not always be preferred for certain soils, many farmers
modify their equipment to successfully use some type of conservation tillage
system on most soils. An example of this is strip-till, where the planter is modified
by adding multiple coulters and/or row cleaners to remove more crop residue and
create strips of bare or deep-tilled (using in-row subsoil shanks) soil.
A similar concept is applied in the northern Cornbelt by what most farmers
there call "fall strip-till." Fall strip-till is usually associated with deep banding of
nutrients in the fall to improve no-till corn production on poorly and somewhat
poorly drained soils. The idea is to dry and warm the soil quickly for planting (see
page 26 for more on fall strip-till). Care should
be taken, however, since strip preparation techniques can significantly reduce crop residue
cover levels, particularly when performed in fragile crop residues such as soybean stubble.
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