Tillage Effects on Some Soil Physical and Corn Physiological Characteristics

Abstract

AbstractTillage systems influence soil temperature and available soil water, which can influence photosynthetic rates and growth of corn (Zea mays L.). Field experiments were conducted in 1987 and 1988 in New York on a tile‐drained silt loam soil (fine‐loamy, mixed, nonacid, mesic Aeric Haplaquept) to determine to what extent conventional tillage (CT), no‐till (NT), and ridge tillage (RT) systems influence soil temperature and soil water conditions, thereby influencing CO2 exchange rates (CER) and growth of corn. Soil temperature at the 0.1‐m depth under NT averaged about 1 °C lower than CT and RT during the first 50 d after emergence (DAE). In 1987, when water stress was not a factor, the lower soil temperature under NT resulted in lower leaf, stem, and total phytomass throughout the vegetative period. Kernel growth rates, however, did not differ between tillage treatments (33.2, 30.9, and 31.4 g m−2 d−1 for CT, NT, and RT, respectively) which resulted in no differences in kernel phytomass at physiological maturity (1125, 1000, and 1030 g m−2 under CT, NT, and RT, respectively). During the hot and dry 1988 growing season, soil water pressure under CT at the 0.25‐m‐soil depth decreased to −0.1 MPa at 44 DAE, 13 d earlier than under NT anti RT. Cone index values were higher under NT and RT from the 0.07‐ to 0.22‐m‐soil depth which indicates increased soil mechanical resistance under NT and RT. The CER were significantly lower under NT or RT compared to CT on 8 of 10 measurement dates during a dry period in 1988 (34‐54 DAE) which was reflected in lower leaf, stem, and total phytomass during the vegetative period. Likewise, NT had a lower kernel growth rate (19.6 compared to 27.4 and 23.4 g m−2 d−1 under CT and RT, respectively), which resulted in lower kernel phytomass at physiological maturity. The data suggest that increased soil mechanical resistance can develop under a continuous NT and RT system which can decrease soil water uptake, CER and growth of corn when dry conditions occur during vegetative development.