Tillage and rotation effects on soil physical characteristics
2002
Farmers are adopting different cropping systems, so our objective was to identify tillage x rotation interactions for soil physical characteristics in the sixth year of a tillage (moldboard plow, chisel, and ridge) x rotation [continuous corn (Zea mays L.), soybean [Glycine max (L.) Merr.]-corn and soybean-wheat (Triticum aestivum L.)/clover (Trifolium pretense L.)-corn] study. Moldboard plow had lower penetration resistance (0.97 MPa) and bulk density (1.19 g cm(-3)) and greater infiltration (75 micrometer s(-1)) and porosity (-2.5 to -40 kPa soil water potential) compared with ridge tillage (1.39 MPa, 1.31 g cm(-3), and 24 micrometer s(-1), respectively) at the sixth leaf (V6) stage and greater infiltration (106 and 31 micrometer s(-1), respectively) during early grain fill (R3) of corn. In ridge tillage, the interrow had lower penetration resistance (1.10 Mpa) and bulk density (1.28 g cm(-3)) and greater infiltration (35 micrometer s(-1)) vs. the row (1.68 MPa, 1.34 g cm(-3), and 13 micrometer s(-1), respectively) at V6 but greater penetration resistance (3.13 and 2.46 MPa, respectively) at R3. The soybean-wheat/clover-corn rotation had the greatest earthworm densities (504 m(-2)) and infiltration (68 micrometer s(-1)) among rotations at V6. Earthworm densities and infiltration explained about 25% of corn yield variability, which may have contributed in part to the 15 to 40% yield advantage for corn in the soybean-wheat/clover-corn rotation in moldboard plow. Tillage x rotation interactions did not exist for soil physical characteristics, so 5-yr tillage effects would be consistent across rotations.
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