ABSTRACT If benefits of conservation tillage can be
quantified even in the transition year from conventional tillage,
growers will more likely integrate practices that maintain or enhance
soil quality and productivity. The management of surface residue is an
important component of conservation tillage, especially in cool, rainy
climates where
vegetable growth and yield reductions have been observed when heavy residue is present. Cereal rye (Secale cereale L.), grown until flowering, was killed with glyphosate and was then cut
and removed (stubble treatment) or rolled or chopped to form a surface
mulch (mulched treatment) before transplanting cabbage. Rolled mulch
increased soil wet aggregate stability by 4% and reduced soil
penetrometer resistance by up to 0.5 MPa compared with rye stubble
treatments in 2003. In 2004, frequent rains saturated soils and may
have accelerated the decomposition of chopped mulch, minimizing
treatment effects. Rolled mulchreduced soil temperatures by up to 2.8°C
in 2003, but June transplanting of cabbage probably minimized the
impact of soil temperature. Mulched treatments did not delay cabbage
maturity or affect head quality characteristics such as color or
uniformity. Although rolled mulch reduced cabbage growth by as much as
30% and yield by 21% in 2003, chopped mulch did not affect growth or
yield in 2004. Yield reduction may be over come by killing the rye
relatively early in the spring or retaining only the surface stubble;
these strategies may maintain or measurably improve soil quality even
in the transition year to conservation tillage.
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