Maize Genomics and Genetics 2025, Vol.16, No.5, 258-266 http://cropscipublisher.com/index.php/mgg 259 2 Plant Density and Maize Yield 2.1 Effects of high vs. low plant densities Planting more densely often allows maize to make more full use of resources such as sunlight and nutrients, so that the yield per unit area may increase. However, planting too densely can easily cause maize to compete for resources, such as light and nutrients, which will affect their growth and ear development (Figure 1) (Djalović et al., 2024). If the density is too high, the leaf area and photosynthesis capacity cannot keep up, and the leaves age quickly, which will cause the yield to stagnate or even decrease (Wu et al., 2023). On the other hand, planting too sparsely reduces competition, but it will also waste land and resources, and fail to use up the sunlight and nutrients of a piece of land, resulting in a lower yield per hectare (Assefa et al., 2018). Figure 1 Regression model trendlines of grain yield depending on planting density, categorized by FAO groups. R2 = coefficient of determination; Xmax = estimated maximal planting density; Ymax = estimated maximal grain yield (Adopted from Djalović et al., 2024) 2.2 Optimal plant density under different conditions The most suitable density for planting maize actually depends on the specific situation, such as the variety selected, the climate, the soil, and how to manage it. On the calcareous soil of the Southern Pannonian Basin, the most suitable density for hybrids of different maturity is about 57 600 to 68 700 plants per hectare. In North America, the density of maize planting there has been increasing in recent years, especially in high-yield areas, where the density has increased and the yield has also increased significantly (Lacasa et al., 2020). In the model of planting maize and peanuts together, 9 plants/square meter is considered to be a relatively ideal density, which can ensure maize yield without affecting the peanut harvest (Zhang et al., 2020). In addition, the study found that if the density can be arranged according to the local sunlight intensity, the effect will be better. In places with strong solar radiation, the planting density can be appropriately increased (Liu et al., 2021). 2.3 Interaction with other agronomic factors Planting density often needs to be coordinated with other planting management methods, such as how much nitrogen fertilizer to apply and what variety to use. If the density is increased, the amount of nitrogen fertilizer should usually be adjusted accordingly to ensure that the yield does not drop and that resources are better utilized
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