Higher Population and Twin Row Configuration Does Not Benefit Strip Intercropped Corn

Increased corn (Zea mays L.) grain yield with strip intercropping, made possible because of increased edge effects, makes this soil-conserving crop production system appealing to farmers. The objective of this study was to determine the population and row configuration needed to optimize the additional yield potential in each outside corn row. Treatments \u27included: 74, 99, and 124 thousand plants ha-1 were grown in twin rows and 74 thousand plants ha-1 grown in single rows. Single rows or twin row centers were spaced 0.76 m. The experiment was conducted at four central Iowa sites during 1996 and 1997. Grain yield was not increased by increasing population, nor did it respond consistently to the twin row configuration. There was little interaction between row position in the strip and treatment response. Higher plant population decreased the number of ears per plant, kernels per row, and kernel weight. The twin row configuration increased the number of ears per plant, but this was offset by a decrease in the number of kernels per row and kernel weight. Farmers should follow current cropping recommendations until this optimum is determined. Given the inconsistent grain yield response to twin rows, there is no current rationale for investing in twin row planting equipment