Response of Sweet Corn to Red Clover Under Two Tillage Methods

ABSTRACT

A study was conducted in 1999–2001 in central Maine to compare the effects of a spader plow versus a rototiller on nitrogen mineralization and growth of sweet corn (Zea mays L.) following red clover (Trifolium pratense L.). Spring wheat (Triticum aestivum L.) was established the first year of the rotation, with and without a red clover co-seeding. The following spring, clover and wheat stubble were incorporated with either a rototiller or a spader plow, which incorporates the residue deeper and with little or no chopping or tearing. Sweet corn was planted with no additional N inputs. Sweet corn growth and yield parameters were monitored, as was soil nitrate and total mineral N throughout the corn growing season. In both 2000 and 2001, sweet corn after clover yielded significantly more (p < 0.05) in all yield parameters than sweet corn after no clover. There were no significant differences in sweet corn yield parameters between the two tillage treatments in either year, although there was a consistent trend for sweet corn after clover to yield higher in rototilled plots than spaded plots. In both years total N content of corn biomass was greater in the rototilled than in the spaded treatment following clover. Soil nitrogen monitoring showed that in both 2000 and 2001, soil nitrate and total mineral N were greater early in the season under the spaded treatments. Corn grown under this treatment utilized available nitrate after clover less efficiently than in the rototilled treatment.

KEYWORDS:

• Cover crops
• clover
• sweet corn
• tillage
• rototiller
• spader
• nitrate