Planting date and residue rate effects on growth, partitioning, and yield of corn

Corn (Zea mays L.) growth has been shown to be affected by planting date and amount of residue on the soil surface. The objective of this study was to determine if the adverse effects of cool soil temperatures on early seedling growth often associated with surface residues can be overcome by planting at later dates. Corn was planted at several planting dates (late April through early June) into soil that had residue applied at rates of 0, 33, 66, and 100% of that produced by the previous crop. In general, spring-applied residue rates had little effect on measured plant responses. Planting corn before or after the optimum date resulted in reduced leaf area index, leaf area duration, total dry matter production, and grain yield. Maximum yield was achieved by planting corn about 10 May (near Lincoln, NE), regardless of the amount of residue applied in the spring. Yield declined with earlier or later planting dates: yield declined more rapidly when planting was delayed than when planting was advanced. Results indicate that, with spring residue application, planting date recommendations can be made independent of residue conditions.