Chapter 3 - Maize water use and yield in the solar corridor system: a simulation study

Abstract

The Solar Corridor system is an agronomic approach to increase crop yields by using wide row spacings. Row spacing interacts with plant population and the arrangement of plants within the row. The results of studies to address plant population and row spacing effects on yield and water use in maize are sometimes conflicting and depend on other factors such as climate, hybrid, irrigation, and planting date. The objective of this study was to use a maize simulation model with a 2D soil process model (MAIZSIM) to investigate the interactive effects of maize hybrid, climate, and plant population on water use efficiency (WUE) and yield of maize. The simulations used soil properties for two soils found in Iowa with contrasting water-holding capacities, two plant populations (3.7 and 6.2plantsm−2), two row spacings (0.75 and 1.20m), and three hybrids (early maturing, medium, and late maturing). Thirty years of daily weather data were generated by the program CLIGEN. The model was tested for response to plant population against data from the literature. The simulations showed that row spacing did not significantly affect yield, WUE, or transpiration. For the same plant population and variety, intercepted light was lower for the wider row spacing. Yields were higher for the high population treatments but only for the short- and midseason varieties. Yields for the long season hybrid were not different from the midseason suggesting that the longer period of grainfill for the long season hybrid was not an advantage because of decreasing day length and cooler temperatures. There was a slight yield advantage to the wider spacing under water stress. This research suggests that, for the conditions used here, wider row spacing (to 1.2m) and higher plant populations generally result in higher yields. The model was useful for the purposes of this study and could be used to explore a wider range of management, soil, and climate conditions.