Corn and Soybean Production as Affected by Rotational Tillage Systems

1. Corn and Soybean Production as Affected by Rotational Tillage Systems Jeffrey A. Vetsch* and Gyles W. Randall, Univ. of Minnesota, Southern Research and Outreach Center, Waseca, MN Abstract Rotational tillage systems may be advantageous in the northern Corn Belt because of time savings, conservation compliance, and minimal to no yield penalty compared with long-term no-till. The objectives of this 4-yr study were to quantify the effects of rotational full-width tillage compared with long-term no-till and zone-till systems with and without in-season row cultivation on corn and soybean production. The study was conducted on a tile drained, Nicollet-Webster clay loam soil complex (Aquic Hapludolls and Typic Endoaquolls, respectively). Tillage treatments consisted of a factorial combination of three factors: (i) tillage for corn following soybean [no tillage (NT), deep zone tillage (ZT), strip tillage (ST), and spring field cultivate (SFC)], (ii) residual effects of tillage for soybean following corn [NT or chisel plow (CP)], and (iii) in-season row cultivation for corn (with or without). Corn grain yields averaged 9.6, 10.1, 10.1, and 9.7 Mg ha-1 with NT, ZT, ST, and SFC tillage for corn, respectively. No tillage for the previous year’s soybean crop reduced corn yields in two of four years compared with CP tillage. Soybean seed yields were reduced with NT for soybean in one of three site years. Rotational tillage practices can be effective in reducing the risk of yield loss and managing residue accumulation on these poorly drained soils. Objective The objective of this study was to quantify the effects of rotational full-width tillage compared with long-term no-till and zone-till systems with and without in-season row cultivation on corn production and in-row soil penetrometer resistance on a tile drained, clay loam soil in south-central Minnesota. Materials and Methods Soil type: Nicollet (Aquic Hapludolls) and Webster (Typic Endoaquolls) clay loam complex Experimental design: RCB design with a three-factor factorial arrangement, 4 reps of corn and soybean each yr. Plot size: Three m (four 76-cm rows for corn and six 51-cm rows for soybean) wide by 18 m long. Tillage treatments: Tillage for corn following soybean: no-till, zone-till (38-cm depth), fall strip-tillage (15-cm depth), and one-pass spring field cultivate (SFC). Tillage for soybean following corn: no-till and chisel plow + SFC. Row cultivation of corn: with or without. Penetrometer resistance measurements: Taken in-row with a standard ASAE 30°, 12.8-mm cone in 15-mm increments to a 600 mm depth. Severe gulley erosion can be a result of inadequate residue cover (left). Deep zone tillage (38 cm) of soybean stubble for next year’s corn crop (middle). Mole knife used for fall strip tillage (right). Planting corn into strip-till zones (left). Corn grown with conventional and no tillage (middle). Soybeans grown with no tillage and chisel plow + SFC tillage (right). Results (Yield, Residue Coverage and Economic Return) Results (Soil Penetrometer Resistance) Observations Corn grain yield Yields were 0.4 to 0.5 Mg ha-1 greater with zone-till and strip-till for corn compared with spring field cultivate (SFC) or no-till. Yields were increased in 2 of 4 years when chisel plow + SFC tillage was used for the previous year’s soybean crop compared with no-till. Plant height at 35 days after corn emergence Plant heights were decreased 7% when no tillage was used for the previous year’s soybean crop compared with chisel plow + SFC. Residue cover after planting corn Residue cover was 67, 41, 56, and 41% with no-till, zone-till, strip-till and SFC, respectively. Residue cover was decreased 11 percentage points when chisel plow + SFC tillage was used for the previous year’s soybean crop compared with no tillage. Corn economic return Tillage for corn did not affect corn economic return. Corn returns were increased in 2 of 4 years when chisel plow + SFC tillage was used for the previous year’s soybean crop compared with no-till. Averaged across years, returns were $4 ha-1 greater with chisel plow + SFC. Soybean yield Soybean yields were greater in 2 of 3 years with chisel plow + SFC tillage for soybean compared with no tillage, but when averaged across years were increased only 0.07 Mg ha-1. A significant tillage for soybean by tillage for corn interaction was shown by chisel plow + SFC tillage for soybean increasing yields compared with no tillage for soybean only when no tillage or zone tillage was used for the previous year’s corn crop. Residue cover after planting soybean Residue cover was decreased 46 percentage points with chisel plow + SFC tillage for soybean compared with no tillage. Soybean economic return Soybean returns were decreased in 2 of 3 years with chisel plow + SFC tillage for soybean compared with no tillage. Averaged across years, chisel plow + SFC tillage decreased returns $6 ha-1. Figure 1. In-row soil penetrometer resistance as affected by tillage for corn in April (preplant), May (emergence), and June (V4) of 2000. Figure 2. In-row soil penetrometer resistance as affected by tillage for corn in May of 2000, 2001, and 2002. Observations (Penetrometer Resistance) Generally, zone and strip tillage for corn reduced in-row penetrometer resistance (PR) compared with SFC and no tillage. Although some reconsolidation occurred, reductions in PR with zone and strip tillage remained through V4 and were consistent from year to year. Penetrometer resistance never exceeded the 1.5 MPa threshold where corn root restrictions may occur. Acknowledgement Financial assistance for the project provided by Deere Co. was greatly appreciated. References Lazarus, W., and R. Selley. 2005. Farm machinery economic cost estimates for 2005. Univ. of Minnesota Ext. Serv., Univ. of Minnesota, St. Paul.