GROWTH-DEVELOPMENT AND YIELD OF MAIZE UNDER 3 TILLAGE SYSTEMS IN THE NORTHEASTERN USA

Cool spring temperatures are a major constraint to maize (Zea mays L.) production in northern regions of the U.S.A., and a no-till (NT) system intensifies the problem because residue on the surface further decreases soil temperature. Ridge tillage (RT), because of the configuration of the ridge and the removal of most of the residue from the seed zone during the planting operation, may alleviate this problem. Field experiments were established in New York on a drained and undrained silt loam soil (fine-loamy, mixed, nonacid, mesic Aeric Haplaquept) to examine the influence of a fall-plowed, or conventional tillage, system (CT), NT, and RT on soil temperature growing degree days (GDD) and subsequent growth, development, and yield of maize in continuous production. Soil GDD averaged about 35-40 GDD less under NT during the first 35 days after emergence, which resulted in a consistent three-day delay in silking and a lower maximum leaf area index (LAI) and crop growth rate (CGR). Under drained conditions, grain yields under NT averaged 10% lower than CT (8.68 and 9.60 Mg ha-1, respectively). In two of the three years, however, higher CGR under NT duringv the grain-filling period resulted in the same total phytomass and grain yields as under CT. Soil GDD averaged about 10 GDD more under RT than under CT and the development of maize under RT and CT was essentially the same. Nevertheless, under drained conditions, the growth of maize under RT was slightly slower than under CT and grain yields (9.05 Mg ha-1) averaged 5% lower. In the undrained experiment, where some flooding occurred in two of the three years, grain yields were significantly higher under RT than under CT and NT (7.92, 7.09, and 7.19 Mg ha-1, respectively). In 1988, when a two-day flooding period occured shortly after emergence, the configuration of the ridge reduced the duration of surface flooding from two days to one day, which resulted in increased plant survival, faster growth and development, and higher grain yields (7.36, 5.79, and 5.60 under RT, CT, and NT, respectively). In conclusion, RT appears to be a well adapted conservation tillage system for continuous maize production in northern regions, especially on soils that flood periodically. © 1990.